What is the Tesla Powerwall and should you get one?

    July 14, 2023

The Tesla Powerwall is a rechargeable lithium-ion battery designed to store energy for home use. It is a product of Tesla Energy, a branch of Tesla Inc. that focuses on manufacturing solar energy products. Our friends at EWI Pro have a case study which is garnering regional and national awards; the project in question utilises Tesla Powerwall 2 batteries.

Features of the Tesla Powerwall

  1. Energy Storage: The Powerwall is a rechargeable battery system that stores energy from solar panels or the grid. It stores surplus solar energy not used at the time it is generated and provides that energy when needed later on, such as during the night or during a power outage.

  2. Compact and Scalable: The Powerwall is compact and entirely automated. It’s a relatively small, rectangular unit that mounts to the wall, typically in a garage or outside of the home. Multiple Powerwalls can be connected to increase the amount of power available. Up to 10 Powerwalls can be combined for homes with greater energy needs.

  3. Real-Time Energy Usage: The Tesla app gives you an overview of your home’s energy production and consumption in real time. It shows solar production, Powerwall charging and discharging, and home energy use.

  4. Touch-safe: The Powerwall has a touch-safe design, which means there are no exposed wires or hot vents.

  5. Water-Resistant and Dustproof: It is water-resistant and dustproof, allowing for installation indoors or outdoors.

  6. Storm Watch: Powerwall can detect incoming storms using internet-connected data and will automatically store energy in preparation for power outages.

  7. Self-Powered Mode and Backup-only Mode: The self-powered mode allows you to use the Powerwall to power your home independently from the grid. On the other hand, the Backup-only mode stores energy until the Powerwall detects a power outage, at which point it starts supplying power.

  8. Time-Based Control: Time-Based control lets you use the Powerwall’s stored power when energy costs are high and recharge when costs are low (this requires a compatible electricity tariff).

  9. Integration: Powerwall can be integrated with Tesla’s solar panels and Solar Roof for an all-in-one solar and storage system.

  10. Temperature Control: Powerwall uses an internal liquid cooling and heating system to keep its internal temperature stable, which can improve battery performance and lifespan.

Should you get a Tesla Powerwall?

Should you get one? The answer to this depends on a few factors:

  1. Availability of Solar Power: If you live in an area that gets a lot of sunlight throughout the year, a Powerwall, in combination with solar panels, could save you a significant amount on your energy bills.

  2. Power Outages: If you live in an area that experiences frequent power outages, the Powerwall’s backup power capabilities could be a valuable asset.

  3. Energy Prices: In some areas, electricity prices can vary throughout the day. If you live in such an area, you could save money by charging the Powerwall during off-peak hours and using the stored power during peak hours.

  4. Cost: A Powerwall is a significant investment. The cost of a Powerwall (not including installation or supporting hardware) is upwards of £15,000. You would need to calculate the potential energy savings over time to see if it would be a cost-effective choice for you.

  5. Environment: If reducing your carbon footprint is a priority, using a Powerwall in combination with solar panels can help achieve that goal by decreasing your reliance on grid energy, which often comes from fossil fuels.

  6. Local Regulations and Incentives: Some areas have laws, regulations, or financial incentives related to renewable energy installation and storage. These can influence the cost-effectiveness of a Powerwall.


Tesla Powerwall models


Technology and costs

The Tesla Powerwall, employed at an elephant sanctuary in Kenya, is designed for daily cycling, such as load shifting. The company utilises its proprietary technology for cell packaging and cooling with a liquid coolant. Musk has pledged not to pursue patent infringement lawsuits against anyone utilising Tesla’s Powerwall technology in good faith, mirroring his earlier promise with Tesla cars.

The first Powerwall utilises a nickel-manganese-cobalt composition and comes with a warranty that covers up to 5,000 cycles. With a round-trip efficiency of 92.5% when charged or discharged by a 400-450 V system at 2 kW and a temperature of 25°C (77°F), the Powerwall’s performance is top-tier when new. However, variations in the product’s age, temperature above or below 25°C (77°F), and charging or discharging rates above 2 kW may reduce this efficiency, thereby affecting overall performance.

The original Powerwall includes a DC-to-DC converter that sits between a home’s existing solar panels and the current DC-to-AC inverter. Should the current inverter not be compatible with storage, a suitable one must be procured.

The second iteration, Powerwall 2, features a DC-to-AC inverter designed by Tesla. The production of the 2170 cell type for the Powerwall 2 commenced at Giga Nevada 1 in January 2017.

In 2016, the National Fire Protection Association carried out two worst-case scenario tests, igniting Powerpacks to initiate thermal runaway. The design successfully contained the damage within the Powerwall structures.

An article published in Forbes magazine in May 2015 calculated that integrating a Tesla Powerwall 1 model with solar panels in a household would render electricity costs at about 30 pence/kWh if the home remained connected to the grid. This scenario painted the Powerwall as a luxurious, eco-friendly accessory for wealthy individuals.

Both Bloomberg and Catalytic Engineering concur that the Tesla system proves most beneficial in areas with high electricity costs, such as Hawaii and other remote islands that generate electricity using imported fuel.

Areas with time-of-use (TOU) pricing may also see potential savings. For instance, Northern California’s Pacific Gas and Electric Company 2021 charged rates as low as 12 pence/kWh during off-peak hours (12a–3p) and as high as 52 pence/kWh during peak hours (4p–9p). When configured for cost savings, the Powerwall can enable a home to go off-grid during peak hours, thus avoiding high-cost power usage.

According to the Swiss bank UBS, the Powerwall makes economic sense in countries like Australia and Germany, where electricity is exceptionally costly but solar panels are widely distributed.

As of October 2019, the recommended installation of two Tesla Powerwall 2 units costs around £11,000 (plus £1,900 to £3,400 for installation) in the US, excluding the cost of solar panels.

    What is AeroBarrier and how can it help your home?

    June 16, 2023

AeroBarrier is an innovative technology designed to enhance airtightness. It has been successfully implemented in the USA, Canada, and the UAE, and has now been introduced in the UK.

AeroBarrier functions by sealing air leaks in buildings with a specific mist that consists of tiny particles that form an airtight barrier. This mist is spread inside the building, and as it moves, it detects and seals any openings or leaks in the building’s structure. The mist particles are driven by air pressure and accumulate to form a continuous seal, effectively blocking unwanted airflow.

AeroBarrier guarantees its efficacy up to a certain level of airtightness, either aligning with the UK building standard of 8 m3/hr.m2 or the Passivhaus standards of 0.6 m3/hm3.

Why is controlling airflow in a home important?

Airflow is essential in maintaining a healthy and energy-efficient home. It can be divided into two categories: intentional and unintentional airflow.

Intentional Airflow:

Intentional airflow is designed to provide ventilation to the interior of a home. This is a critical aspect of maintaining indoor air quality. Ventilation helps to:

Unintentional Airflow:

Unintentional airflow, or air leakage, happens when outside air enters and conditioned air leaves your house uncontrollably through cracks and openings. These can occur around windows, doors, electrical outlets, plumbing points, and where the structure is not entirely airtight. Unintentional airflow can lead to several issues:

Airflow Management in Homes:

There are several strategies homeowners can use to manage airflow effectively:

By combining these strategies, homeowners can control airflow in their homes, improving comfort, indoor air quality, and energy efficiency.

What are the building airtightness regulations?

In the last year, new building regulations have been put in place in England and Wales to enhance the requirements for airtightness in new constructions.

These regulations have reduced the air permeability limit in new buildings from 10 m3/hr.m2 to 8 m3/hr.m2. Other significant updates have been made to airtightness regulation as well.

While these changes are not overly strict, they signify the start of a process predicted to lead to even stricter standards in the future, as the UK aims to lower carbon emissions and increase energy efficiency in homes.

By enhancing airtightness, the regulations aim to reduce heat loss and improve the overall energy performance of new and existing buildings, a goal shared by AeroBarrier. Tim Crump, the founder of Oakwrights, the company that introduced AeroBarrier to the UK, claimed, “Britain has some of the least efficient and oldest housing stock in Europe, and there is a real and growing interest in improving energy efficiency and reducing environmental impact.”

Is AeroBarrier suitable for your project?

AeroBarrier is incredibly versatile and can be used on various types and sizes of buildings, making it suitable for both new constructions and renovations of existing structures. It has been widely used across the United States by architects, builders, and homeowners.

While AeroBarrier is highly effective at sealing air leaks, it is important to protect surfaces during its application. The sealant may not stick easily to vertical surfaces but settles well on horizontal surfaces.

As a safety measure, windowsills and finished floors should be protected during application to avoid any undesirable contact with the sealant.

How much does AeroBarrier cost?

The cost of AeroBarrier can vary widely depending on a variety of factors. These include the size and complexity of the building, the level of airtightness required, the current state of the building, and the location of the project. A typical residential application in the U.S. could range from a few thousand dollars to over $5,000.

However, prices might have changed since then and may be different in the UK, so it’s advisable to get in touch with a local AeroBarrier installer or Oakwrights for the most accurate quote for your specific project.

It’s also worth noting that while the upfront cost may seem high, improving a building’s airtightness can result in substantial savings on energy bills in the long run. The energy saved by reduced heating and cooling requirements can offset the initial investment over time. Moreover, enhanced indoor air quality and comfort are also significant benefits of airtight buildings, which are not directly quantifiable in monetary terms but contribute to overall well-being.

    Natural building materials

    April 28, 2023

Natural building materials are gaining popularity as more people become conscious of their environmental impact and seek to minimise it. This shift towards eco-friendly construction encompasses a wide range of building fabric materials such as timber, mineral wool, wood fibre, cork, wool insulation, lime plaster and render, thatch, clay and slate roofs. In this blog post, we will explore some of these materials and their benefits, focusing on cob, straw bale, cork, hempcrete, limecrete, and green roofs.

Timber, Mineral Wool, and Wood Fibre

Timber is a highly sustainable building material when sourced from responsibly managed forests, where trees are replanted, and ecosystems are preserved. Its natural aesthetic adds warmth and character to structures, and it can be easily repurposed or recycled at the end of its life. Timber’s ability to absorb CO2 during growth and store it for its lifetime significantly reduces its carbon footprint.

Mineral wool insulation, made from natural rock or recycled slag, provides fire resistance and prevents mould growth, ensuring a safe and healthy living environment. Its excellent thermal and acoustic insulation properties contribute to reduced energy consumption and a quieter indoor environment, leading to lower energy bills and increased comfort.

Wood fibre insulation, a byproduct of the timber industry, is an eco-friendly alternative that offers high insulation performance and moisture regulation. Its breathability contributes to a healthier indoor climate, reducing the likelihood of respiratory issues and allergies caused by trapped moisture and mould.

Cork and Wool Insulation

Cork insulation is harvested from the bark of cork oak trees without causing harm to the trees or their ecosystems, allowing for sustainable resource management. Cork insulation is durable, resistant to moisture and pests, and provides excellent thermal and acoustic insulation. Its insulating properties lead to reduced energy costs and a more comfortable living environment.

Wool insulation, sourced from sheep’s wool, is a natural, renewable, and sustainable option. Its breathability helps to regulate humidity levels within a building, reducing the risk of condensation and mould growth. Wool insulation also offers superior insulation performance, which reduces energy consumption and improves indoor comfort.


Lime Plaster and Render, Thatch, Clay, and Slate Roofs

Lime plaster and render are eco-friendly alternatives to cement-based products. Their breathability allows moisture to escape, preventing mould growth and contributing to a healthier indoor environment. Lime products have self-healing properties, which reduce maintenance requirements and extend the material’s life. Lime also has a lower embodied energy than cement, resulting in lower CO2 emissions during production.

Thatch, made from reeds or straw, is a traditional roofing material with excellent insulation and weather resistance properties. Its insulating capabilities contribute to reduced energy consumption, while its natural appearance adds charm and character to a building. Clay and slate roofs, made from natural materials, are durable, long-lasting, and low maintenance. Their minimal environmental impact over their lifespan makes them a sustainable choice for roofing.

Thatched roof

Cob, Straw Bale, and Cork

Cob, a mixture of clay, sand, straw, and water, offers several benefits as a sustainable building material. It is affordable and can be locally sourced, reducing transportation costs and emissions. Cob walls provide excellent insulation and thermal mass, helping to regulate indoor temperatures and reduce energy consumption, resulting in lower heating and cooling costs.

Straw bale construction is energy-efficient and resource-conscious. The high insulation levels provided by straw bales lead to a low carbon footprint and minimal impact on natural resources. The breathable nature of straw bale walls contributes to a healthy indoor environment, while their thermal performance ensures a comfortable living space. Straw bale construction is also relatively low-cost and can use locally sourced materials, reducing the overall environmental impact of the building process.

Cork, in addition to its insulation properties, can also be used as a building material for walls. Its thermal and acoustic insulation, as well as its resistance to moisture and pests, make it a sustainable and comfortable choice. Cork walls provide a natural aesthetic and contribute to a healthy indoor environment by regulating humidity levels and minimising mould growth.

Straw bale house

Hempcrete and Limecrete

Hempcrete, a bio-composite material made from hemp fibres and a lime-based binder, is a sustainable alternative to traditional concrete. Its lightweight nature reduces the need for extensive structural support, while its breathability offers excellent insulation and thermal mass, resulting in lower energy consumption and a comfortable living environment. Hempcrete is also resistant to mould, pests, and fire, ensuring a safe and healthy living space. As hemp is a rapidly renewable resource with a short growth cycle, using hempcrete significantly reduces the overall environmental impact of construction.

Limecrete, a mixture of lime and aggregates, is another eco-friendly alternative to concrete. It provides a breathable and flexible floor or wall system that allows moisture to escape and prevents mould growth. Limecrete has a lower embodied energy than traditional concrete, resulting in reduced CO2 emissions during production. Additionally, limecrete’s flexibility helps to accommodate ground movement, reducing the likelihood of cracks and improving the structure’s durability.


Hempcrete – https://www.ukhempcrete.com/gallery/gallery-hempcrete/

Green Roofs

Green roofs are an innovative and eco-friendly way to integrate nature into the built environment. They involve covering a roof with plants, which provide insulation, stormwater management, and habitat for wildlife. Green roofs can reduce energy consumption by providing additional insulation, which helps to regulate indoor temperatures. They also improve air quality by absorbing pollutants and producing oxygen, contributing to a healthier urban environment.

Moreover, green roofs contribute to urban biodiversity by providing a habitat for insects, birds, and other wildlife. They can also help to mitigate the urban heat island effect by reducing the amount of heat-absorbing surfaces in cities. By implementing green roofs, urban areas can become more resilient to climate change and provide a more sustainable, healthier living environment for their residents.

Green roofs


Natural building materials offer numerous benefits, from improved energy efficiency to reduced environmental impact. By embracing these sustainable materials, we can contribute to a greener future for our planet. Whether you are building a new home or looking for ways to upgrade your current space, consider incorporating natural building materials like timber, cork, hempcrete, or green roofs into your design. By doing so, you’ll not only create a comfortable and healthy living space but also contribute to a more sustainable world.

    Insulating the loft and floors

    March 17, 2023

The most effective way to combat heat loss is certainly external wall insulation; however, loft and floor insulation is also crucial. The best way to tackle an insulation project is with a whole-house approach. Whilst 35% of heat loss is through external walls, a significant portion is still lost through the loft and floor. The loft in particular is very simple to insulate and can even be done as a DIY project, although we would always recommend a professional.

Ways to insulate the loft

There are several ways to insulate a loft or attic, including:

  1. Roll insulation – This is a cost-effective and easy-to-install option where rolls of insulation are placed between the joists.

  2. Blown insulation – This involves using a machine to blow insulation material, such as cellulose, into the loft space. It can be a quick and effective option, especially for irregularly shaped loft spaces.

  3. Spray foam insulation – This is a more expensive option, but it provides excellent insulation and can help to seal any gaps or leaks in the loft space.

  4. Insulated plasterboard – This option involves installing insulated plasterboard onto the ceiling of the loft space. This can be a good option if you are planning to convert the loft into a living space.

  5. Reflective insulation – This type of insulation is made up of reflective material that reflects heat back into the loft space. It can be a good option for hotter climates or if your loft space is exposed to direct sunlight.

It is important to consider the R-value (a measure of thermal resistance) of any insulation material you choose and ensure that it meets local building codes and regulations.

Roll insulation

Roll insulation is a type of insulation that comes in long rolls, typically made of fibreglass, rock wool, or mineral wool. It is commonly used in attics and loft spaces because it is affordable and easy to install.

Roll insulation is available in various thicknesses and R-values, which determine its insulating effectiveness. The R-value measures the insulation’s ability to resist heat flow and the higher the R-value, the more effective the insulation is at preventing heat loss or gain. The thickness and R-value you need will depend on your location and local building codes, as well as the climate in your area.

To install roll insulation in the loft, the insulation is rolled out between the ceiling joists or rafters, with the paper or foil backing facing downwards. The insulation should be cut to fit around obstacles such as vents and wiring and should be placed snugly to ensure there are no gaps or spaces where heat can escape.

Roll insulation is generally a DIY-friendly option, but it is important to wear protective clothing, gloves, and a mask when handling the insulation, as it can cause skin irritation and respiratory issues if inhaled. It is also important to ensure that the insulation is not compressed or compacted, as this can reduce its effectiveness.


Blown insulation

Blown insulation, also known as loose-fill insulation, is a type of insulation that is installed by blowing loose insulation material, such as cellulose, fibreglass, or mineral wool, into the loft or attic space using a machine.

Blown insulation is an effective way to insulate a loft or attic space, particularly for irregularly shaped or hard-to-reach areas. The insulation material is blown into the loft space through a hose, which can be directed into hard-to-reach corners or crevices, ensuring that every nook and cranny is insulated.

One of the benefits of blown insulation is that it can be installed quickly and efficiently, often in just a few hours. It can also be a cost-effective way to insulate a loft or attic, as the loose insulation material can be purchased in large quantities and installed in a short amount of time.

Blown insulation can also be a good option for improving the soundproofing of a loft or attic space, as it can help to reduce noise transfer between floors.

It is important to choose the right type of insulation material and ensure that it is installed to the correct depth and density, as this will impact the insulation’s effectiveness. Additionally, blown insulation requires specialized equipment and should only be installed by a trained professional to ensure proper installation and avoid any safety hazards.

Spray foam insulation

Spray foam insulation is a type of insulation that is applied as a liquid and then expands and hardens to form a solid barrier that seals gaps, cracks, and crevices in the loft or attic space. It is made up of two components – a polyurethane or polyisocyanurate foam and a catalyst – that are mixed together and then sprayed onto the surface to be insulated.

Spray foam insulation can be an effective way to insulate a loft or attic, as it can fill even the smallest gaps and spaces, providing a complete air seal and preventing heat loss or gain. It is also an excellent sound barrier, reducing noise transfer between floors.

One of the benefits of spray foam insulation is that it is a very efficient insulation material, providing a high R-value per inch of thickness. It can also be a good option for people with allergies, as it does not provide a hospitable environment for mould, bacteria, or other allergens.

However, spray foam insulation can be a more expensive option compared to other types of insulation. Additionally, the installation process requires specialized equipment and should only be done by a trained professional to ensure proper installation and avoid any safety hazards. Spray foam insulation can also emit harmful fumes during installation, so it is important to take proper precautions, such as wearing protective gear and ensuring proper ventilation.

Insulated plasterboard

Insulated plasterboard, also known as thermal plasterboard, is a type of plasterboard that has a layer of insulation material, such as expanded polystyrene or mineral wool, attached to the back. It is designed to be used as both a wall and ceiling covering and is commonly used in loft conversions or other spaces where additional insulation is needed.

One of the main benefits of insulated plasterboard is that it provides both insulation and a finished surface in one product. This can be particularly useful in the loft or attic spaces that are being converted into living areas, as it can save time and money on installation and finishing.

Insulated plasterboard is available in a range of thicknesses and R-values, which determine its insulating effectiveness. The thickness and R-value you need will depend on your location and local building codes, as well as the climate in your area.

Insulated plasterboard is attached directly to the wall or ceiling using screws or adhesive. The joints between boards are then taped and filled to create a smooth, finished surface.

Reflective insulation

Reflective insulation is a type of insulation that works by reflecting heat back towards its source, rather than absorbing it like other types of insulation. It typically consists of a layer of reflective material, such as aluminium foil, that is backed by an insulating material, such as polyethene foam or bubble wrap.

Reflective insulation is often used in the loft or attic spaces to help reduce heat gain in the summer and heat loss in the winter. It is particularly effective in hot climates, where it can help to keep the loft or attic space cooler by reflecting the sun’s heat away from the building. In colder climates, reflective insulation can also help to reduce heat loss by reflecting the heat back into the building.

One of the benefits of reflective insulation is that it is lightweight and easy to install, often requiring no special tools or equipment. It can also be a cost-effective option for those looking to improve the insulation of their loft or attic space.

However, reflective insulation is less effective at reducing heat transfer through conduction, which is the main method of heat transfer in solid materials. Therefore, it is usually used in combination with other types of insulation to provide a complete insulation system.

Ways to insulate the floor

There are several different types of floor insulation that can be used to increase energy efficiency and comfort in a building. Some of the most common types include:

    How Is The UK Getting To Net Zero By 2050?

    February 24, 2023

The UK government has set a target to achieve net zero greenhouse gas emissions by 2050, which means that the country will emit no more carbon dioxide and other greenhouse gases than it removes from the atmosphere. Achieving this ambitious target requires a wide range of measures across all sectors of the economy, including energy, transport, industry, agriculture, and buildings.

What is Net Zero in global terms?

Net zero refers to achieving a balance between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. The goal of net zero is to reduce the overall level of greenhouse gas emissions to limit the increase in global temperatures and mitigate the impacts of climate change.

Achieving net zero involves reducing greenhouse gas emissions through various measures, such as transitioning to renewable energy sources, improving energy efficiency, and implementing carbon capture and storage technologies. Any remaining emissions that cannot be reduced must be offset by removing an equivalent amount of emissions from the atmosphere, such as through reforestation or other forms of carbon sequestration.

The concept of net zero is increasingly being adopted by countries, cities, and businesses as a way to address the urgent need to reduce greenhouse gas emissions and combat climate change. Many countries have set targets to achieve net zero emissions by mid-century or earlier, and there is growing momentum for a global transition to a net-zero economy.

Strategies for getting to Net Zero by 2050

Some of the key strategies that the UK is adopting to reach net zero by 2050 include:

  1. Investing in renewable energy sources: The UK government has pledged to increase the proportion of electricity generated from renewable sources to 50% by 2030 and is investing in offshore wind, solar power, and other clean energy technologies. As a result of the war in Ukraine, this push for renewable sources has grown, as the supply of fossil fuels has been cut. 

  2. Phasing out fossil fuels: The UK is gradually phasing out the use of fossil fuels in power generation, transport, and industry. The government has announced plans to ban the sale of new petrol and diesel cars and vans from 2030 and is investing in public transport infrastructure, cycling, and walking. The UK’s fossil fuel dependency is gradually dropping, however, the dependency was still at 78.3% in 2021, as per Statista. The drop is significant compared to the 96.5% in 1970 but needs to accelerate significantly to achieve the net zero target by 2050.

  3. Improving energy efficiency: The UK is taking steps to improve the energy efficiency of buildings, appliances, and industrial processes. The government has introduced regulations requiring all new homes to be built to a high energy efficiency standard and is offering financial incentives to homeowners and businesses to upgrade their properties. Previously, the Green Homes Grant was available to homeowners, however, it was vastly unpopular and ineffective. Much of the funds were redistributed at the end of the scheme, and it was replaced by the ECO4 scheme, which is due to be supported by the ECO Plus scheme.

  4. Carbon capture and storage: The UK is investing in carbon capture and storage (CCS) technology, which captures carbon dioxide emissions from power plants and other industrial processes and stores them underground.

  5. Tree planting and land use: The UK is increasing tree planting and other land-use measures to absorb atmospheric carbon dioxide. The government has targeted increasing tree planting to 30,000 hectares per year by 2025.

UK power sector e missions over time

UK power sector emissions over time – https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1128689/mission-zero-independent-review.pdf

How is the UK getting on so far?

The seminal resource for the current state of the Net Zero objective is ‘MISSION ZERO, Independent Review of Net Zero’, conducted by Rt Hon Chris Skidmore MP. He makes several conclusions that indicate what has been achieved and where more significant action is required:

So what are the benefits for the public?

The drive toward Net Zero is a goal that requires total participation amongst the public. Encouragingly, around 50-60% of the UK is already taking steps to reduce its carbon emissions in some way. If that figure continues to grow in line with increased efforts by the Government, the goal is achievable. As a result, the public can reap significant benefits, including the following:

What if we don’t reach Net Zero?

The major risk of failing to reach Net Zero is the increased impact of climate change. We are increasingly likely to see changes in temperature, rainfall, and sea-level rise.

Temperature – Increased chance of summers like 2018, wherein extra energy is required to power fans and refrigeration.

Rainfall – More rain in the winter and less rain in the summer, resulting in different water management, and potential droughts.

Sea-level rise – Continue to rise under all emission pathways.

Our partners at EWI Store post new technical, practical, and theoretical blogs about external wall insulation every Tuesday! Link below.

    An introduction to loft insulation


Why should I install loft insulation?

Insulating your loft is one of the best ways to improve the EPC rating of your home. If you have a virgin loft (i.e. 25mm or less of insulation) then insulating it will produce massive savings on your energy bill and the great thing is that for many of us, the energy companies offer this insulation free.

Without proper loft insulation, a lot of the warmth produced by your heating system escapes through the roof of your property; in fact, as much as 25% of the heat in an uninsulated house is lost in this way. Loft insulation acts as a barrier, slowing the movement of heat out of the property during the winter and into the property during the summer.

Even if you can’t get it installed for free, it is an incredibly easy DIY job. In the tabs above, you can find out exactly how to do it.

The first decision to make is whether you are looking to create a warm loft or cold loft. The majority of us just use the loft space for storage so normally a cold loft will more than suffice, but for some we use the loft space for a games room or a study. To be honest, insulating your loft as a cold loft is far easier than trying to produce a warm loft – mainly because you don’t need to fight gravity. The method of insulating your loft varies considerably whether you have decide to push forward for a warm loft or a cold loft, but since the vast majority go for a cold loft lets start there – at the joists.

Insulating your loft at the joists

The purpose of insulation is to produce a barrier that slows the movement of heat either in or out of the property. When you produce a cold loft, you need to lay insulation directly above the ceiling to produce this barrier to slow the movement of heat out of the home during the winter and visa versa in the summer to prevent the home overheating.

The latest building regulations stipulate you need to reach a U-value of 0.16 to conform – now for most of us who don’t talk ‘U-values’, this simply means you need a 300mm blanket of wool insulation (if you decide to use rigid insulation board like celotex or Kingspan then you can achieve this u-value with less thickness).

What materials can you use to insulate joists?

Mineral wool

We describe the main types of wool insulation in detail here. Each have their own advantages and disadvantages, but all of them work in a similar way. The wool traps air, which provides an insulating barrier. They are all fairly easy to work with, in that they can be cut to measure, shaped to fit around immovable objects and also rolls of wool insulation are cheap.

The main issue with wool insulation is that it compresses if you put any weight on it, which lowers its insulating efficiency. If you lay wool insulation to a depth of 270mm, it is also difficult to locate the joists, which you should use as support if you are in the loft space. Never stand between the joists, otherwise you will more than likely come through the ceiling!

Wooden boards can then be laid over all the insulation if you need to make the loft usable for things like storage. The insulating mineral wool used normally comes in rolls of blanket, which is a consistent thickness and width.


Sheep wool insulation

If you are using sheep wool insulation you will get the added benefits of the material being able to absorb moisture as well. Warm air rises from the heated rooms below and condenses when it comes into contact with cold insulation materials. Unlike other wool products, sheep wool can absorb some of this moisture and protect the joist timbers from rotting, without affecting its own insulating properties.

Loose-fill loft insulation

Insulating your loft floor using loose-fill is great as a top-up process for a pre-insulated space. It tends to be light material such as recycled newspapers and mineral wool, which can be spread to cover any gaps between the joists. You simply open the bags of insulating material and pour into any spaces that were previously lacking an adequate level of insulation. This process is a fairly simple do-it-yourself job.

Rigid insulation boards

These boards, produced by companies like Celotex, are ideal for insulating loft spaces. They are more expensive than the wool, however they offer double the insulating capacity (therefore where you would normally use 270mm of wool, you would only require 135mm of the insulating board). In addition, since they are rigid it is easy to store items directly on top of them without laying board on top of them first. They can be cut to size using a saw to fit between the joists and also drilled to allow room for light fittings.

Blown fibre insulation

Another type of loft insulation is blown fibre insulation, which must be installed by a professional. An installer will use specialist equipment to blow insulation material into the gaps that require it.

Having a carpet of insulation in your roof will significantly reduce heat loss out of your home. The reason why we are such advocates of loft insulation and consider it the no.1 method of saving energy in the home is basically because the insulation is incredibly cheap to buy and the process of producing a cold loft is so easy.

Now a couple of important things to mention; while this is certainly the cheapest way to go, the loft space itself will be very cold in the winter. This means that anything you really value should be kept in the home itself, not in the loft. In addition you need to insulate any pipework and cold water tanks up in the loft as these may now be liable to freezing and the cost of repairing bursting pipes will far outweigh the energy savings produced!

For detailed instructions on how to insulate your loft to produce a cold loft please click the tab here.

Insulating your loft at the rafters

Gravity is a pain – it makes producing a warm loft that much harder. Unfortunately if one tries to insulate between the rafters by squishing in lots of wool insulation then 9 times out of 10 it will just fall out.

However if your heart is set on creating a warm loft space then it is definitely possible. There are four main ways to insulate your rafters; the first is to use netting and wool insulation. Using solid insulation board is again a really good way to minimise heat loss out of your home. The third way is simply to use reflective foil stapled to the rafters – this doesn’t produce significant energy savings but is by far the simplest way to go, requiring just reflective foil and a staple gun. You might want to use reflective foil anyway even if you do opt for a cold loft.

What materials can you use to insulate between rafters?

The materials you should use to insulate the rafter space will depend on the way you have chosen to insulate, however the products used will tend to be denser and more rigid than those used for joists.

Normally the process you decide on depends how deep the actual rafters are. If the depth is rather shallow the best option will be to insulate below the rafters. You can in theory increase the depth yourself by attaching planks of wood top of the rafter, but then you are giving yourself more work and adding complexity to the process.

Mineral wool for insulating between the rafters

This can be glass wool, rock or mineral wool and it comes in rolls. You will need to wear protective material, a mask and have the adequate tools to fix this to the space between the rafters. The material is then fixed to the space between the rafters, whilst ensuring there is gap to the roof membrane to avoid condensation.

The difficulty in creating a warm loft with mineral wool insulation is basically due to the thickness of wool insulation needed to hit the necessary U-value as specified by building regulations (300mm) although to be honest, if you are doing this yourself, you are not required by law to conform. The way to keep the insulation in place is to use a net that you can then staple to the rafters which acts as a hammock for the insulation.

Sheep wool for insulating between the rafters

If you are using sheep’s wool, which is not an irritant, then you can handle the material without wearing protective clothing. If you are using sheep wool insulation you will also get the added benefits of the material being able to absorb moisture. Warm air rises from the heated rooms below and condenses when it comes into contact with cold insulation materials. Sheep wool, unlike other wool products, can absorb some of this moisture and protect the rafter timbers from rot, without it affecting its own insulating properties. When insulating rafters, a more rigid form of sheep’s wool insulation can be used, which is more suited to rafter insulation.

Insulation boards for insulating between or below the rafters

Insulating board can be fitted between the rafters or below the rafters. Note: Because the material is thick, if you are going below the rafter space you will certainly lose headroom in the loft space. If your rafters are shallow then you have no choice and have to insulate below.

These boards, produced by companies like Celotex or Kingspan, are ideal for insulating loft spaces. They are more expensive than the basic mineral wool, however they offer double the insulating properties (therefore where you would normally use 200mm of wool, you would only require 100mm of the insulating board). They can be cut to size using a saw to fit between the spaces and drilled through for cabling.

Reflective foil for insulating below the rafters

A thin layer of reflective material is placed below the rafters to prevent heat escaping from the property. This is the most simple way to insulate your loft via the rafters, but obviously the insulating properties on this type of insulation are very limited compared to either mineral wool or insulating board.

As mentioned, the foil is by far the easiest way to insulate your loft; you simply staple it to the rafters. It is worth starting at the apex of the ceiling and then working down the rafters, overlapping the foil to achieve a continuous reflect surface. You can then tape over the joins.

Spray foam

A layer of foam is sprayed into the rafters and sets hard. This can only be installed professionally.

When professionals come in and install spray foams, they can achieve high thermal efficiency with very little depth. The two downsides of this firstly that it is very expensive compared to the other methods and also it doesn’t allow the roof to breath, locking in the water next to the timber – which as we have mentioned previously can lead to problems.

While having a warm loft space is great because you can then use the space – you are now heating an extra ‘room’ that you wouldn’t normally heat if you insulated just above the ceiling (i.e. a cold loft) – which means your heating bill will be higher.



Installing loft insulation

Interested in installing loft installation? The Green Homes Grant is a Government run scheme, offering grants of up to £10,000.

If you are interested in this scheme, we advise you look in to this on the Government website.

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      Draught proofing windows

    Do my windows need draught-proofing?

    Not all windows need to be draught-proofed. Double or triple glazed windows installed since 2002 should be sufficiently well-built and installed so as not to require any. Older double glazing and single glazed windows can be draught-proofed, however. If you are unsure on the age of your double glazing, you should check for either a FENSA certificate, which you will have received with any windows installed since 2002, or a stamp in the metal seal of the window.

    Where to look for draughts

    1. The gaps between the window and the frame
    2. Caulk on the outside of the window frame
    3. The area around any locks or catches

    Although the potential for draughts to occur around the edge of one window is not equal to that of an external door, the accumulated draught from every window in your house can account for huge amounts of energy loss. Therefore it is crucial to draught-proof these areas. In order to complete a successful draught-proofing of a window, you must firstly pinpoint the gaps that require work. After locating the area that requires draught-proofing, there are a few methods to consider.

    How can I draught-proof my windows?

    How should I draught-proof a window that opens?


    Firstly, compression seals provide a professional finish and prevent draughts, as well as dust and moisture entering the home. The seals are sometimes held by metal, plastic or wooden carriers, which are fixed onto the frames through pre-drilled fixing holes. This maintains the ‘memory’ or ‘bounce-back-ability’ of the seal, enabling it to return to its original shape even after periods of crushing, due to normal everyday use of the window. The carrier is cut to length and must be less than 25mm from the cut end to avoid any snagging on unwanted items such as clothing. However they may also be glued to the frame. While these compression seals, as well as the similar tubular seals, provide excellent performance on narrow window gaps, they are not the best option when draught-proofing sash windows on larger properties.

    How should I draught-proof a window that doesn’t open?

    The best method for draught-proofing a window that does not open is a silicone-based sealant. After the gaps in the framework have been located and cleaned to remove any dust that may reduce the longevity of the draught-proofing method, a gunned silicone sealant can be easily applied. This is a cheap and easy way to DIY draught proof.

    How should I draught-proof a sash window?


    If you are looking to draught-proof a sash window or if the gaps between the window and its frame are not consistent due to seasonal changes, brush strips may provide the best solution. While mainly used in the draught-proofing of doors, it is not rare to see this method around larger windows. This solution involves brushes or blades fixed into a carrier, which is pinned onto the frame. While they may be painted to reduce their visibility, this does decrease their efficiency. However the brushes or blades may be contained using wooden carriers, which may provide a more aesthetically-pleasing solution to window draughts.

    Another method of draught-proofing your window, and common when taking the DIY approach, is low-friction seals in loose strips or carriers. This solution involves the rubbing of wipers or blades, which are fixed onto the frame, against the closing window. While they may also be fixed using an adhesive-based foam strip, this method (although cheap) does not comply with British standards and is therefore not recommended.

    Using gunned silicone as a sealant


    A DIY-friendly and relatively cheap solution to your window draught-proofing needs is gap-filling seals with gunned silicone sealant. In order to ensure that maximum draught-proofing is achieved, you must cover the part of the window that comes into contact with the frame in a release agent. This prevents the sealant from sticking to the window as opposed to the frame. The window is then shut to provide a temporary mould for the sealant before it sets. While it provides an efficient solution to the draught-proofing issue, if it isn’t carried out correctly, the result may look untidy.

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        Insulating Your Loft Joists: a Step-by-Step Guide


      As we mentioned in our Introduction, there are two main ways to insulate your loft: one is via the rafters and the other is by insulating your joists. Insulating the joists is often the easier of the options and especially makes sense if you have no real plans to use the loft space.

      Key points before you start

      If your loft is easy to access, the insulating process should be pretty straightforward and can be undertaken as a DIY job. However, if you have any doubt in your own ability to carry out the work, we recommend getting a professional to do it.

      Normally, people use mineral wool (either glass fibre or Rockwool) to do the job and if you intend to do the same it is imperative you wear protective clothing, goggles and a face mask, since the wool is an irritant.

      You can use sheep wool insulation, which is much nicer to handle, 100% sustainable and actually is more breathable than the other types of wool insulation. If you are happy to pay a little extra we really recommend using this.

      As a final warning, never stand between joists otherwise you will more than likely come through the ceiling which is never ideal. Using a board supported by several joists is the best way of working in the loft area regardless of whether you are insulating the joists or the rafters.

      Preparing the loft space ready to insulate

      Before you get to the business end of installing loft insulation up in your roof, you need to make sure you have prepared the loft space and also bought the right quantity of materials to do the job. Below is a quick step-by-step guide on what you should do before you begin any work – but before this a quick word of warning!

      Please remember not to step in between the joists – otherwise you will end up falling through the loft! Make sure you only stand of the joists themselves, ideally using a plank as a kneeling board.

      A kneeling board should straddle several joists, thereby spreading the weight more evenly and reducing the load on the joist structure. The board should go across at least 3 joists to ensure it spreads the weight sufficiently. We also recommend covering your skin with suitable clothing and using a face mask, as stray fibreglass can act as an irritant if it comes into contact with skin.

      Before installing the loft insulation:

      Once you have the loft space ready to insulation we recommend doing a quick equipment check – below is a list of all the equipment you will need:

      • Tough pair of scissors to cut the loft insulation
      • Measuring tape
      • Protective overalls and gloves when handling mineral wool (otherwise it is itchy!)
      • Safety goggles
      • A disposable mask

      The protective overalls, gloves, goggles and mask are really worth using – the mineral wool insulation most people tend to use to insulate the loft is incredibly itchy, so making sure your skin is covered is a good way of avoiding this.

      Using sheep wool insulation is another way to get around the itch issue.

      Measuring the size of your loft

      After you have cleared bulky objects you can see the area more clearly on what you can insulate. When measuring your loft space you need to start with the following:

      Write down these measurements on a piece of paper and then take them with you to a DIY shop to buy the insulation or visit an online retailer. Just a word of warning: insulating wool is really bulky and so unless you have a huge car, you might be better off having it delivered directly to your home.

      Installing loft insulation between the joists

      Insulating the loft at joist level is actually pretty easy to do as a DIY job, but if you feel uncomfortable doing the work then please call in a professional. Since different insulation products have slightly different insulating properties, building regulations use a U-value that needs to be attained to conform. This allows you to calculate the thickness of your chosen insulation product required to conform with building regulations, for example if you opt to use mineral wool, you will need to use 270mm-thick insulation to reach the 0.16 U-value specified in building regs.

      To insulate your loft at joist level, please follow the steps below:

      STEP 1: The first thing to do is to check whether there are light fittings that protrude between the joists (e.g. a GU10 spotlight will always have the fitting protruding into the loft), if there are, these will require capping prior to laying any insulation. These caps, sometimes referred to as downlight fire hoods or insulation guards, allow sufficient space around the light fitting for the heat to dissipate to stop the light getting too warm. Each light fitting will require a cap to prevent this overheating – they are simply placed over the light fitting and then you are good to go with the insulation.

      STEP 2: The first layer of wool insulation needs to be laid between the joists, so you need to measure the distance between the joists to ensure you can get the right width of product. Typically the gap between the joists is either 380mm or 570mm so you will need a width of insulation similar to this, so it can fit snugly between the joists. Most insulation you buy will be partially perforated, allowing you to cut the roll of insulation easily to produce either 2 rolls that are 570mm wide or 3 rolls that our 380mm wide. If the insulation isn’t partially perforated, you will need to use scissors to cut it to the necessary thickness.

      STEP 3: Once the insulation is the correct width, you need to roll it out between the joists; lightly press the insulation material to fit between the joists, but be careful not to overdo it and compress the material. Joists tend to be only about 100mm high (although this can vary), so match the insulation thickness you buy with the joist height – once installed, the insulation should come up to the top of the joists. You will need to work the insulation around and over any downlight caps that may now be present.

      STEP 4: You now need to spread an additional 170mm – 200mm thick insulation at 90 degrees to the joists. Starting at the furthest point from the loft hatch slowly unroll the insulation over the top of the joists – make sure you use kneeling boards to spread the weight load and reduce the risk of ceiling collapsing as you move around in the loft space. This second thicker layer of insulation should have no gaps between the strips that you lay out – it should produce a continuous layer of insulation – you will no longer be able to see the joists. This will take the total thickness of the insulation in the loft to 270mm – 300mm as specified by building regulations. You may like to install even thicker than this, but the energy savings of doing so will be negligible.

      STEP 5: As a final step you will need to insulate the loft hatch, by strapping on some material to the top of the hatch. This can be stapled to the top of the loft hatch, helping to preserve a consistent thermal barrier. You can also fit draught proof strips on the outside of the hatch to stop gusts of cold air in the winter. A really easy way to do this is to fill a black bag with insulation and then tape this down to the top of the hatch using thick tape.

      Although 270mm – 300mm is the optimum depth recommended for mineral wool, but if you are planning on using one of the other insulating materials such as loose fill, it is worth reading the guidelines provided by the manufacturer to ensure you use a sufficient volume to give the required depth. Putting more than 270mm on insulation within your loft (e.g. 350mm) will help you heat your house for less, but the savings equal the cost of laying the additional insulation so you may deem this unnecessary.

      Storing items in the loft but still insulating to building regulations

      As we have said, the more insulation the better and to adhere to building regs you need 270mm of wool insulation as a minimum. One of the issues with putting this much insulation in the loft space is that you lose sight of the joists. Many people like to use the loft space as storage, however, so will insulate only to the top of the joists and then attach chipboard directly to the joists making a solid, walkable surface. Obviously if you install 300mm this is not possible, so prior to STEP 4 above, you will need to install loft stilts (or loft lifters).

      These are relatively simple to install, and are essentially strong plastic stilts that raise the height of the joists, allowing you to install the extra insulation and then attach chipboard on top of the them. This allows you to still produce a useable surface while also maximising the thickness of insulation you install.

      Using rigid insulation board as loft insulation

      Some people may prefer to use rigid insulation board to insulate the loft space – for example Celotex or Kingspan – the process is pretty similar to above, although you will need less depth to achieve the same insulation levels (than mineral wool). You will also need a hacksaw to cut the insulation to size. If you do decide to use rigid insulation board, then you will still need to use chipboard if you want to walk on it.

      Insulating water tanks in the loft

      One issue that arises from insulating the loft space just above the ceiling (i.e. in the joists) is that the loft space itself will become incredibly cold. During very cold weather the temperature could even become sub-zero, which if you have water tanks in the loft, could be a big issue!

      If you do have cold water tanks in the loft, first of all, never insulate underneath them; always allow heat to travel up through the roof into the bottom of the cold water tank. Also, it is worth insulating the cold water tanks themselves and lagging any pipework you can see in the loft that sits above the insulation you have installed in the joists. The kit required to insulate the cold water tanks is known as the Byelaw 30 and can be purchased from any good DIY store.

        Solid Wall Insulation


      What is solid wall insulation?

      If your house was built prior to the 1930s, the chances are that it will have solid walls – simply a solid layer of masonry bricks. Insulating your walls – regardless of whether they are cavity or solid (or even timber-framed) – is a great way to make your home more energy efficient. The insulation will minimise heat loss in the winter, saving you money on your heating bills. It will also stop your home getting too warm in the summer, helping to keep your home at a more comfortable temperature.

      According to research, twice as much heat could be lost through an un-insulated solid wall as through an un-insulated cavity wall. However, the great news is that solid walls can be insulated, both internally and externally.

      The science behind insulation

      If hot air and cold air are partitioned by a wall, heat will transfer through the wall, eventually cooling the room until an equilibrium is reached (where the outside temperature is equal to the inside temperature). In reality this very rarely happens, because rooms tend to be heated; so as heat escapes through the wall, more hot air is supplied by your heating system, keeping it at a comfortable ambient temperature. If the thermal gradient is larger, for example on a cold and wintry day, the movement of the thermal energy across the wall will be accelerated.

      Insulating a solid masonry wall helps to provide a thermal barrier, which helps to slow the movement of heat escaping out into the external environment.  Less heating is therefore needed to keep the house at the required temperature.

      Types of solid wall insulation for your home

      Both internal and external insulation are great at keeping your home warmer, lowering your heating bills and cutting carbon emissions. However, both solutions have a different impact on your home, which is explained in the following section:

      Internal solid wall insulation

      There are a couple of methods to insulate a solid wall internally, which are either to use a rigid insulation board or build a stud wall. We recommend you get a professional in to complete this type of work, and you do not undertake it as DIY unless you are very experienced. Internal solid wall insulation can be as thick as 100mm, so your room will ‘shrink’ wherever it has an external supporting wall.

      One way to avoid losing floor space is by using insulating wallpaper, which at only 10mm gives you some benefit of internal solid wall insulation, without impacting on the size of your room. However, the insulating wallpaper will not give you the same performance of dry-lining with the insulation boards unfortunately.

      Advantages of internal wall insulation

      Disadvantages of internal wall insulation


      External solid wall insulation

      For external wall insulation, you need to employ a professional and you also need to consider local building regulations. This is because this process involves covering the original brickwork and could significantly alter the current appearance of the property, making out of step with the local area. Once any planning permission has been granted, the home can be insulated using an adhesive material which is fixed to the wall, then plastered over.

      The finish applied to the external wall can be any combination of texturing, painting, tiling, brick slips, masonry work and/or cladding.

      Advantages of solid wall insulation

      Disadvantages of solid wall insulation

      Costs of solid wall insulation

      Measuring the effectiveness of solid wall insulation

      The R-value is the measure of thermal resistance used in the building and construction industry today. The higher the R-value, the better the insulating properties of a material – so you should be looking to insulate your house with materials displaying a high R-value. Confusingly, you may hear the word U-value also bandied around. This is exactly the opposite, describing the ability of a material to conduct heat, so you want your insulating material to have a low U-value.

      Installing solid wall insulation

      Interested in getting solid wall installation? Lucky for you, we work in partnership with EWI Store who specialise in external wall insulation systems! They have a great team who are always happy to help with your enquiries.

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          Cavity Wall Insulation


        Why get cavity wall insulation?

        A home can lose as much as 35% of its heat through uninsulated external walls. By investing in cavity wall insulation, you can significantly reduce the heat loss from your home. The concept of insulating a cavity wall is really very simple – it involves filling the cavity between the two skins of masonry bricks with an insulating material, which slows the movement of heat through the wall. Maintaining the heat inside your home keeps you warm and cosy when you need to be. It also works in reverse by keeping your house cooler in the summer months.

        Installing cavity wall insulation in your home will not only help to decrease your heating bills by saving energy lost through the walls, it will also help to reduce your carbon footprint by limiting the amount of CO² and other greenhouse gases emitted from your property.

        Many houses since the late 1930s were built with a cavity between the inner and outer walls. Because of this cavity, many of Britain’s homes have thermal performances which are well below the standards required by current building regulations. These properties suffer from unacceptably high levels of heat and energy loss through the walls. A system was introduced in the 1970s to inject insulation into these cavity walls.

        Can I get cavity wall insulation?

        There are two things you need to determine to see whether you can benefit from retrofitting cavity wall insulation in your home.

        The first thing is to work out if you actually have cavity walls – this might seem stupid, but you can not inject insulation if there isn’t a cavity and they do look quite similar to solid walls!

        A cavity wall is made up of two masonry brick walls running parallel to one another with a space (cavity) between them of at least 50mm. Masonry bricks are very absorbent, so moisture absorbed by the outer wall typically drains through the cavity, rather than coming into the home, helping to prevent damp issues. This type of wall construction became the norm in the 1930s superseding solid walls and as time has gone on, the size of the cavity between the two skins of brick has continued to grow – a typical cavity wall now is between 280-300mm thick.

        You can easily identify a cavity wall by the pattern produced by the brickwork, which is known as stretcher bond, where are the bricks are running in the same direction as one another – there are no ‘half bricks’. This is obviously harder to do if your walls are cladded or painted and in this case you might need to call in a professional (although sometimes you can see original brickwork in the loft space). In addition cavity walls tend to be over 250mm in width, with more recent cavity walls closer to 300mm. If you can see lots of half bricks in your wall, you have a solid wall with no cavity, so unfortunately cavity wall insulation is a no-go. In this case, you could look into external wall insulation as an alternative.

        Once you have established that you have cavity walls, you need to determine the size of the cavity and whether it has previously been insulated. A registered installer will need to come and carry out a boroscope inspection. This involves drilling a test hole into the wall and checking with a camera to see if the cavity has previously been filled and the size of the cavity (ideally over 50mm). If this shows the cavity is unfilled, you could indeed benefit from cavity wall insulation.

        Although some builders began insulating cavity walls in the late 1970s, it only became compulsory under building regulations to do so during the 90s. As such there are many properties in the UK that currently have unfilled cavity walls. The good news it that these can be insulated very easily!

        How does cavity wall insulation work?

        If a hot room is partitioned from the cold by a wall, heat will move through the wall, eventually cooling the room until an equilibrium is reached, where the outside temperature is equal to the inside temperature. In reality this very rarely happens, because rooms tend to be heated. This means that as some heat escapes through the wall, more hot air is supplied, keeping it at a comfortable ambient temperature. If the thermal gradient is larger, (e.g. on a cold and wintry day), the movement of thermal energy across the wall will be accelerated.

        Insulating a cavity wall helps to provide a thermal barrier, which slows the flow of heat out of a room considerably. By slowing down the rate at which heat escapes from the home, less heating is needed to keep the house at the required temperature. In the summer, the reverse happens; hot air outside the home can’t get in as easily, which means you don’t need to use energy to keep the home cool. Therefore in both summer and winter, cavity wall insulation can make an enormous difference to your energy bills. The process is relatively quick and inexpensive, so it is certainly worth considering.

        How do you insulate cavity walls?

        The first thing to note is that you cannot retrofit cavity wall insulation as a do-it-yourself job – it is a job that needs to be carried out by a professional.

        Once the cavity has been confirmed by the boroscopic inspection, the installer will drill a series of 22mm diameter holes into the mortar between the bricks. With specialist equipment, the installer will then inject the cavity with the insulating material, through each of these holes. Once the whole of the cavity wall has been filled, the mortar will be made good either with plugs or mortar created to match the existing colour, so the job will be barely noticeable.

        Cavity walls being Injected

        The insulating material pumped into the cavity is normally a type of glass wool, or in some instances insulating beads and once installed will offer insulation for the life of the building. The whole process should only take about 2 hours but obviously if the cavity wall area is especially large you will need to leave more time for the job to be completed.

        What materials are used for cavity wall insulation?

        Expanded polystyrene (EPS) foam, loose polystyrene beads, or wool. EPS is the most expensive option for a reason; it is a premium product and we would always recommend spending the extra money for the best results.

        Savings from cavity wall insulation

        Although the savings from cavity wall insulation vary greatly from property to property, for an average size three bedroom home, the energy savings from installing cavity wall insulation should amount to £250 per year. With an installation cost of £600-1000, the savings you create from installing the cavity wall insulation should pay for the work in under 4 years.

        Getting cavity wall insulation in the Green Homes Grant

        If you are eligible, you can now get a grant of up to £10,000, using the Green Homes Grant scheme. The grants are available until March 2022 and are being offered to properties in England.

        There are two grants within the Green Homes Grant. First is the £5000 which most are eligible for if they have cavity walls. However, if you are receiving one of the below benefits, then you may be eligible for the £10,000 grant.

        If you are interested in the Green Homes Grant, we advise you look at the Government website.

        Paying for cavity wall insulation yourself

        Unfortunately schemes like the Green Deal have now finished, but the Green Homes Grant is still available for cavity wall insulation. 

        If you are interested in getting cavity wall insulation installed, we work in partnership with EWI Store who have a network of approved installers. So please fill in the form at the bottom of this page, and we will be in contact with you shortly.




        Installing Cavity Wall Insulation

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        If you would like us to find you a local insulation installer, just fill in the form below and we will be in touch shortly!

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