What are air source heat pumps ?
Air source heat pumps convert heat energy from the air to provide heat and hot water for dwellings. They run on electricity, but are incredibly efficient (in some cases 300% or more), which means that for every one unit of electricity used, they produce 3 units of useful heat.
If you compare that to a brand new boiler which is 90% efficient (1 unit of gas produces 0.9 units of useful heat), you can quickly see why these systems are so popular. In fact, if you don’t have access to mains gas, heat pumps are definitely the way to go to fulfil your heating and hot water requirements – provided you have a well insulated home, which is discussed later.
Better still, if you decide to install an air source heat pump in your home, you can also benefit from the Renewable Heat Incentive, which pays you for each unit of hot water water you produce. In some cases, the funding will cover the cost of installing the heat pump, but it gets paid over 7 years on a quarterly basis, so you will still need to find the money upfront!
How do air source heat pumps work in your house?
The air source heat pump needs to be located outside in the open air, and uses a fan to draw air into it. This air then flows over a heat exchanger, which contains a refrigerant liquid. An evaporator uses the latent heat from the air to heat the refrigerant liquid sufficiently until it boils and turns to a gas. This gas is then compressed by a compressor, which causes it to significantly increase in temperature. An additional heat exchanger removes the heat from the refrigerant (turning it back to a liquid), which can then be used as useful heat. There are two types of air source heat pump:
Air-to-water heat pumps
Air to water heat pumps are by far the most popular. These take heat from air outside the property and transfer this to water, which can be used for space heating or as hot water for washing within the house.
Air-to-air heat pumps
These remove latent heat from the air outside the property which is then simply fed into the home through fans. This type of heat pump cannot be used to produce hot water.
>>> The cost of heating your home with gas vs electricity <<<
Air source heat pumps require electricity to run
Since they include fans and compressors, air source heat pumps require electricity to operate, and bearing in mind the price of electricity is approximately 15p / kWh and gas is just 4p / kWh, on the face of it, you would expect heat pumps to be far more costly to run than gas boilers.
This is not the case though – since for every kW of electricity used to run them, they provide approximately 2.5-3.5kW of equivalent useful energy (depending on the model and the temperature of the external air). This makes running costs comparable to a traditional gas boiler.
The efficiency of air source heat pumps is measured by the Coefficient of Performance, which is simply how many units of useful energy produced from each unit of electricity are consumed to operate the system. For example, if at any moment the heat pump was producing 3kW of useful heat from each unit of electricity, the CoP would be 3.
The CoP varies throughout the year, with lower figures achieved during the colder months (meaning they are running less efficiently), since there is less ambient heat available to remove from the air. This makes comparing the efficiency of different heat pump systems very difficult, so we use what is known as the Seasonal Performance Factor to compare like for like performance of models. This is the annualised CoP, taking into account the different performance throughout the year.
Air source heat pumps don’t produce boiling water
The air source heat pump does not produce the sort of hot water temperature you would associate with a gas, LPG or oil-powered boiler. With a boiler, you would expect the hot water to be heated to about 850c, while a heat pump produces water to about 550c. Trying to increase the water temperature from a heat pump beyond this requires the compressor to work harder, meaning more electricity – this in turn reduces its efficiency or coefficient of performance.
As a result, it is very important to minimise heat loss from the property prior to installing a heat pump. This includes insulating the walls, loft and ideally the floor too. This means that even though the radiators won’t get as hot (using heat pumps), the house is still heated effectively and you are not straining the heat pump – which is expensive.
When installing a heat pump, you may be required to increase the size of some of the radiators in certain rooms too. This is simply because the heat demand will not be met with the existing-sized radiators. If this is the case, you can expect to pay about £200 – £300 for each radiator that needs to be replaced (providing the pipework running to the existing radiator can be reused).
Air source heat pumps and the Renewable Heat Incentive
Heat pumps are part of the Renewable Heat Incentive scheme recently launched by the Government. It means that, if you install a renewable heating technology, you can get paid for each unit of heat you generate. RHI payment rates depend on lots of things, but you can see detailed information here.
Occasionally, but not often, the RHI payments will be enough to cover the cost of the initial outlay of the air source heat pump. Air source heat pumps normally cost between £7,000 – £10,000.In a standard property you can expect to receive a total of about £2-5,000. RHI payments are paid quarterly over 7 years, so you will need to stump up the money up front.
Things to consider before investing in an air source heat pump
Placement of air source heat pump – An air source heat pump requires plenty of space, either to mount on an external wall or to be placed on the ground. The unit needs good air flow, and foreign objects such as boxes, containers etc need to be kept well away.
Cost of air source heat pump system vs system that is being replaced – Purchasing an air source heat pump on top of an existing heating system will prove to be an expensive option; therefore we recommend considering this when replacing an old electric or old oil-fuelled system. However an electric heater will convert 1kW of electrical energy to 1kW of heat energy and an air source heat pump will convert 1kW of electrical energy into 3.5kW (almost 4kW) of heat energy.
Insulation – The air source heat pump emits low temperatures but on a consistent basis. To maximise effectiveness, ensure that your home is suitably energy efficient by installing wall insulation (either cavity or solid wall) and draught proofing. These are low cost measures that will make a big difference to your utility bills, therefore it is worth investing in them prior to replacing your heating system with an air source heat pump.
Noise of air source heat pump – An air source heat pump does make some noise when operating, as both a fan and a compressor will be in motion. The noise is approximately 40-60 decibels (depending on the system) from a distance of one metre away. So please ensure if you invest in an air source heat pump, it is not placed directly outside your bedroom window!
We have filmed an air source heat pump in motion, (don’t say we don’t treat you) so you can see for yourself how they operate.
Efficiency of air source heat pumps – Despite air source heat pumps being able to operate at -250C, the efficiency decreases as the outside temperature drops; therefore if you live in a particularly cold place, you may well need to supplement the heat pump with an additional boiler to get the hot water you require. Try a CHP boiler if you can invest additional resources. The problem may be getting the two systems to work successfully in tandem; therefore a traditional boiler could be your only option.
Local authority regulation for air source heat pump installation
Generally there are fewer restrictions from local authorities in England and Scotland when looking to install an air source heat pump (noise being the main consideration), but please check with your council and installer before proceeding. In Wales and Northern Ireland, an air source heat pump installation requires planning permission.
Benefits
- As the heat pump provides the hot water for heating, there are large savings to be made on fuel bills – typically an air source heat pump can deliver up to 3.5kW of useful energy for every 1kW of energy needed to run it.
- An air source heat pump can still take heat out of the air in temperatures as low as minus 20 degrees.
- By installing an air source heat pump you can reduce your carbon emissions from your homes heating by 50%.
- Air source heat pumps are potential income sources, if households qualify for the government Renewable Heat Incentive (RHI) scheme. The RHI is payable on an MCS ASHP installation, carried out by an MCS Accredited Installer and the payment is backdated to include any installation installed after 15th July 2009.
Limitations
- Air source heat pumps can be fairly noisy, approximately 40 – 65 decibels at a distance of 1m away (however this varies by manufacturer). Look at our video below for some first hand experience.
- The equipment needs to sit outside the house, so may not be suitable if there is not sufficient space.
- Air source heat pumps become less efficient at extracting heat from the air when the external temperature is low, so the amount of usable useful heat they produce is less.
Cost
- An air source heat pump will cost from about £7,000 to install.
Installing heat pumps
Are you thinking about getting a heat pump? We have scoured the country for the best tradespeople, so that we can make sure we only recommend those we really trust.
If you would like us to find you a local heat pump installer, just fill in the form below and we will be in touch shortly!
In france, we have been bought up to use electricity because of all our nuclear power, we don’t use gas in the same way to heat homes. These heat pumps are therefore perfect, I have an air to water source heat pump and it provides hot water & heating for the house (we do sometimes supplement with a wood burner). I cannot recommend them strongly enough – useful article too!
Interesting technology – I live in a council house which has had the walls and lofts insulated. The boiler is quite old and I worry about gas safety. Do you think councils will be installing these as part of a government subsidy?
Berenice our council is going to install bio mass boiler with wet system radiators
Hi Bernice, I don’t at the moment to be honest, simply because the initial install costs are far higher than a new energy efficient boiler.
That being said, if you do have the money lying around – they are definitely worth doing since they are efficient and you can benefit from the renewable heat incentive which is a subsidy payment for getting these installed. Over the 7 years that the the RHI is paid, it should cover the majority of the the install cost.
Had an installer quote £25K for an £8k pump and swapping out of downstairs radiators. He also said the SPF for this make and model is 4.5. It is for a Daikin pump. I have seen you give people here free advice, could you let me know if this is reasonable? Alsk I dont think the installer is Green Deal approved, can I still get a grant as he suggested after it is installed? Thank you.
Hi Ivan,
Thanks for your message. £25K does seem a bit high, but it is difficult for us to comment without seeing yur property. Our recommendation is to always get 3 quotes or more for the work, that way you can be sure you are getting a good deal.
You can still get the RHI with a non-green deal company as long as the installer is MCS accredited – make sure you check this with them, it is really important and ensures their work is to a good standard.
Good luck!
How big are the actual air source heat pump units? I know it will depend slightly on how big a space it needs to service, but I need to know whether it is feasible to squeeze one under a window in the garden. The house has 3 bedrooms and 7 radiators in total, and it is mid terrace (if that provides a view on how big the heat pump needs to be!)
Hi Maggie, if you see James Adams’ answer below, hopefully that will give you a little bit of context. Also feel free to look at the video in the article to give you a real life view. You don’t have to squeeze the pump in, it can be installed further away from the property as long as it complies with the relevant regulation. If you would like, send us an email to mailbox and we can email you some additional real life photographs. Hope that is helpful.
Hi maggie, I installed a Mitsubushi Ecodan (8.5kW) for my house and it is about 1m high by 1m wide. It works incredibly well. I would really strongly recommend them. Informative post though, it covers the heat pumps basics really well.
Hi James
When you say “you” installed a Mitsubishi, Ecodan do you mean YOU installed it or a company did it for you?
As I have been trying to buy one to install myself, but No one seems to want to sell me one, unless they install it,
As I live in France this would be difficult, but am willing to come to UK just to get it, which would be a 3 day round trip by car/van
I am not interested whether the guarantee is valid or not I just want to buy one.
Any comments greatly appreciated.
Hi Alan, we live in a 4 bed bungalow in the countryside. The property currently has a condensing oil boiler but we are thinking of installing a heat pump. The property is of 1950s construction, has timber frame walls and our loft insulation has recently been topped up by ECO. Do you know how much roughly we would be able to gain from the Renewable Heat Incentive? Thank you
Hi Gareth,
The RHI payment will be considerable, because it is a reasonably large property and the wall will not be particularly well insulated. Unfortunately the bad news is that a 50’s timber frame property is not going to be sufficiently well insulated to be able to effectively run a heat pump. You will have to install expensive wall insulation to make the property suitable.
You might be better off considering a biomass boiler, since you live in the country. Insulation is less of a problem with biomass and the RHI is very generous.
Good luck,
Alan
I had a Mitsubishi Ecodan installed in our new build home end of 2013. I have had a Green Deal Assessment as your site suggests so that is all fine, but then I queried the installers for the coefficient of performance. They stated that it is always 2.5 for RHI purposes. Is this correct? As this is slightly different to what you suggest.
I am wondering whether to go air source or ground source heat pump, I know there are big price differences but I have heard the government subsidy pretty much covers install cost, I am more interested in the advantages of one of the other. Any help would be hugely appreciated!
Hi Beatrix, Government subsidies and the initial install cost aside comes down to the performance of the ASHP and GSHP. In the winter, when heat demand is highest – an air source heat pump is tring to pull heat from colder air, so the compressor in the unit has to work harder to drive the temperature of the water up. Basically at the time when you need most hot water, they are running more inefficiently.
Conversely with a ground source heat pump, the temperature under the ground is fairly consistent all year around – this means that the temperature of the fluid returning to the ground source heat pump unit will be relatively even all year round – so the heat pump will never have to work harder at different times of the year, hence a higher seasonal performance factor (and a more even coefficient of performance).
If you have the money and space, the ground source in our opinion are better, purely because of the efficiency in the winter when your demand for hot water is at its highest.
Thanks James, most helpful – we are back here in the UK now so may give GreenAge a call to discuss if that is okay. I think we have space for the GSHP since we have a large back garden and I think you can can drill the holes vertically. The question now is simply whether the Government payments will cover the install cost over the lifespan of it being paid!!
Hi Beatrix, nice speaking to you earlier! Hopefully you are now all set – let us know how you get on!
Just had the first company round to quote for the Ground Source heat pump, he recommended Vailliant which I have had a quick look on the internet about and they seem to get good feedback. It will require two boreholes 120m deep, but they think they could get these drilled by the end of September if we accept the quote!
All very exciting! Again thank you for your help!
I just made a comment on your forum about the Green Deal but I was particularly interested in the air source heat pumps due to the renewable heat incentive. Do you think if we went independent that the subsidies paid would increase? Mr Salmond has promised us a lot, it in him that we trust. A life long unionist but last few weeks has made me think about going yes.
Hi Grant, we don’t comment on politics on this website – we have a strong non-partisan editorial. However what I would say is that if there are changes to geographical borders then we will probably have a significant impact to the energy policy across the UK.
Remember if you are going down the air source heat pump route the best thing you could do is to insulate the roof and the walls as the heating system will operate at a much lower temperature. A well insulated house will make the heating source worth, and this goes beyond the subsidy. It has to be about keeping your bills down whilst being comfortable in the coldest of winter days.
How much more is an air source heat pump today than a biomass boiler? I live in a rural part of Enfield and not unusual for this part of London suburbs that is not on the gas network, but having been running an oil boiler I would like to move to a more sustainable technology.
Just reading all the comments here, amazed people are willing to spend so much on a heating system!
Hi blinks, the RHI makes air source heat pumps and the even more expensive ground source heat pumps well worth installing,especially if you live off grid. I would most certainly recommend installing one of these new heating systems if you can afford the upfront cost. They are actually far more reliable than traditional boiler systems. A really nice helpful concise article. Thanks for sharing
We have just bought a 1960’s ground floor apartment in Eastbourne East Sussex it has old style storage radiators and the hot water is provided with an immersion heater would this system be appropriate and what would it cost please? We will also be refurbishing as it was previously rented.
Look forward to a cheaper system ??
Thank you for your attention to this matter,
Douglas Laurie
Douglas,
Thanks for your comment. Heat pumps are certainly more efficient and you could be looking at savings of a few hundred pounds a year. Unfortunately the costs of switching are quite high – you dont have a wet central heating system so you would need to install this as well as the heat pump. The cost is likely to be pushing £10,000.
In your situation I would recommend looking at infrared heating, as well as the modern quantum storage heaters which are more efficient than your old storage heaters but also much lower cost than a heat pump.
Kind regards,
Alan
We install heat pumps and people are always pleasantly surprised by their performance. This is a great summary article so thankyou for sharing it.
Hi Karen
I am looking to purchase a heat pump. but, I want to install it myself.
I see you say that you install them, can you tell me where you buy them?
I can locate places to get them but they won’t sell it to me because they want to install it.
As I live in France and am restoring an old house I am quite capable of doing it myself.
all the other work has been carried out by me, just need heat pump now to connect it all up.
Any help on this matter would make me very happy chappie.
We had 12kw air source heat pump fitted this summer. The figures so far suggest that it will save us money over the oil fired system that we had previously and the RHI will almost cover the cost of the installation. The noise of the ASHP is much worse than I was led to believe though. I would have looked into a ground source system more closely if I’d known how noisy this system was going to be.
Hi Gerald, thanks for your comments, so we tried doing a few videos to show people how loud heat pumps are (you can access them by clicking here) I guess the key is positioning them correctly – putting them just beneath the bedroom for example is not ideal, but good point – people do need to be aware that air source heat pumps do make a bit of noise.
I’m interested to know what would be involved with installing a ground source heat pump for the upcoming green renovation of our small terraced house.
Our house and property are small at about 4 metres wide and I don’t want to put in an air source heat pump if it’s going to be noisy for our neighbour and also our daughter, whose window the heat pump will sit under after it’s installed..
I’d therefore like to consider a ground source for the heating. Can we have the rods inserted vertically into the ground if we have a small garden? Or could they be laid under the studio that we are having built in the back garden – under the building’s piles?
Looking forward to your replies
Hello James. It is very quiet where I live and perhaps my heat pump is louder than most. I’ve built an enclosure for it (with louvres to allow air movement) and it is quieter now but still louder than the 54 db that the manufacturer claims. Does the RHI payment match inflation the way that the FIT for solar panels does?
Hi Gerald, yes the RHI payments do increase with inflation over the 7 years – you should be able to calculate the payments if you have your latest EPC to hand.
My partner and I looking to move back to our Hampshire cottage having lived in France for 15years. We have been away for a long time so don’t know about the current regimes and schemes that are running to help fund home improvements. In France we were able to get a grant to part pay for our house renovation. However I have heard about the RHI and this helps for air source heat pumps, so do you know whether the rates are the same as they were when it first came out?
Juliet, thanks for your note. The RHI rates are currently as they were when the policy launched in April, however they are under constant quarterly revisions by DECC. The next one is now and the following one at some point in Jan 2015.
We have installed an air source heat pump on the roof of our fairly large 4 bed house. It heats the hot water and provides heating via underfloor pipes. The house is very well insulated and so far it is very warm. My question relates to how best to operate it. The installers insist that we let it run all the time day and night for maximum efficiency. It runs based just on the outside air temperature. There is no internal thermostat. I am no expert but cannot help thinking this is not best for us: (i) we also have photo electric panels and use the electricity generated directly, only selling the surplus to the grid, therefore it appears highly inefficient to me to run the heat pump at night when we are not generating our own electricity, (ii) as it is always cooler at night the heat pump probably works more as it works off external temperature, but this is when it is at its least efficient (iii) we would prefer it to be cooler at night for sleeping . the house retains the heat very well and frankly it is too warm at night (iv) also while the noise is minimal, i would prefer to be without it at night.
Despite the advice of the installer, should i be considering instead to run it based on an internal thermostat, which is set at a lower termperature during the night? He says this would be less efficient and bad for the heat pump.
Hi Chris,
Based on the reasons you have noted – absolutely, run it when you are producing your own electricity!
Hello there. We have a similar problem, did you get an answer to your query.? We also find that as we are in a bungalow the pump is extremely noisy at night and seems to run continuously.
Hello. I am told that ASHPs aren’t noisy but mine certainly seems to be. There are enclosures that cut the noise down. I made my own but they can be bought. In the winter I found that the pump runs almost continuously. These things really aren’t suitable for quiet country locations.
the church near us has one and has spoilt our peace and quite – we can feel the fan cutting in the air at 3am and also feel the vibrations from under the bed – health and safety officers have been good and are recommending to the church that they move it.
the are a waste of time and money
If Worcester bosch are considered the best gas boiler manufacturer, what would the equivalent be in terms of air source heat pumps? I have heard that Mitsubishi do one called the Ecodan but not sure about other brands! Cheers lance
Hi Lance the EcoDan heat pumps are probably the most recognised brand now – they had a huge stand at EcoBuild again this year – I know that is not really a measure of how big a company is, but it impressed us!!
Where can i buy one??????
I have an air source heat pump that was installed by a non-MCS installer. However I have just found out that the Government is giving a generous subsidy towards the cost recovery – should I have the whole system commissioned? Had the air source heat pump put on end of 2012 – it is one of the Vaillant models, if this helps.
I would have it commissioned if you can Matthew – although it may not be possible depending on the unit installed. I would speak to an MCS installer about this – they normally charge about £500 to carry out this service, but because of the RHI payments it is definitely worth doing!
Hi just wondered if i install an ashp at the side of my house can i increase the efficiency by then building a polycarbonate lean too around it.
Hi Steve, no this won’t help because the air in the enclosure will keep getting colder and colder! The key is that there is an air flow so the colder air can be replaced by warmer air as the heat pump functions.
I live out near Alicante in Spain, do you know what seasonal performance factor (SPF) would be in my neck of the woods as I hear in the UK they are a bit wobbly?
Hi James, I couldn’t find anything on the SPF in Alicante, but it is obviously going to better than here in the UK! With any heat pump there is always going to be a significant seasonal variation so in the winter the Coefficient of performance (CoP) will be far lower compared to the summer (the CoP is the efficiency at any one moment). As mentioned though, your SPF is going to be higher since you average temperature in the winter is 12 degrees and here it is about 4-5 degrees!
Hi there, we’re air source and ground source heat pump installers. Clients that we’ve installed heat pumps for are all very satisfied as a heat pump is very easy to maintain and they have already seen savings on their bills. Ground source is a bit more tricky but still a great system, but it does depend on where you are.
Hi, great info!
I live in a semi basement flat some of it under ground built 1880, solid wall construction. some rooms have been tanked and thermolight blocks used. Due to very high cealings (3.2m) I intend to DPM all floors, insulate 120mm kingspan and a underfllor heating system laid in a screed to give a good thermal mass, timer battons and wooden floor, tiles. Ceilings will have lots of insulation mixture of rockwool/kingspan and walls will be clad in 25mm kingspan, battend and infilled with rockwool and clad in plaster board/insulation (celutex) type) As this will then be insulated to the max and partially underground. what is the best heating source fore the underfloor heating, i currently have a gas boiler so have mains gas. i also intend to install a pv and thermal for hot water in the future if and when i can afford it ?
many thanks to my lots of questions !
Hi Dominic, you may go for the air source but to be honest if you have a gas boiler in place that has some life left in it, you may as well stick with. Especially if it is a condensing boiler unit, then it will be quite efficient to operate. Also the price of gas is generally 3 times less than the price of electricity.
I can only have air source and the place has three bedrooms and around 70m2
thanks
EVERYONE SEEMS REALLY IMPRESSED BY THE GHSP AND ASHP BUT FAIL TO MENTION THE CONSTANT LOW FREQUENCY NOISE FROM THEM. WE CAN FEEL AND HEAR OURS CONTINUALLY AND THIS WAS NEVER MENTIONED.
GIVE ME GAS ANYTIME
Hello Linda. Which type of heat pump do you have? I am unhappy with the noise from my ASHP and am thinking about changing it for a GSHP. Are they noisy too?
I installed an eco-Dan air source heat pump last summer. I am actually really happy with it however people need to be aware that the coefficient of performance varies massively throughout the year. During the summer months the coefficient of performance is really high but during the winter it can drop to just one or 1.2. When the manufacturer installed it for us they made no mention of this. Having said that we have underfloor heating and we are very very happy with it.
Would this be a suitable option for a quirky countryside property? The house is large and attracts a lot of sunshine in the warmer months. It currently has storage heaters as it is not connected to the gas grid and it is not possible to install oil central heating because there is nowhere to house the tank (the garden is across the road from the house so therefore cannot be linked to the house without digging up the road!) There is a lot of wall ‘space’ on the sides of the house where a wall mounted system could go.
The property is double glazed and has cavity wall and loft insulation (not floors though). There is a wood burner and a hot water cylinder in the boiler cupboard.
I was wondering as a rough idea what sort of insulation cost we would be looking at as there is no current central heating. The property has 4 large bedrooms, 2 kitchens, 2 sitting rooms etc. so is large.
If this is not suitable are there any other options other than storage heaters and woodburner as it is an expensive system in the cold months?
We provide both air and ground source heat pumps to the domestic and commercial market place. We market Daikin, Panasonic and Jaga. These three in our opinion offer good value for money and are very efficient. We offer free advice on cost, noise and ease of installation. If you would like any information please do let me know.
Hi Trevor, We get a lot of debate on the noise of the heat pumps, please feel free to add your two pennies worth in the comments section if you feel that would help people make a better informed decision on whether to install an air source heat pump.
Hi James, thanks for the welcome. I will put some realistic information about noise up shortly to hopefully enable people to get a better idea of what to expect. On reading through the above comments I noted that buying the product only, was a challenge.
From our point of view the manufactures we deal with insist that we are MCS certified and will not allow us to sell a pump without installation. If we do do we risk losing our certification and authorisation with that manufacturer.
So I sympathise with someone who wants to buy it and as above, take it out of the country and install it themselves but the risks are too great for many installers like ourselves.
THEY ARE A NOISY NUISANCE AND I MEAN NOISY THE FAN CAUSING NOISE ALL NIGHT IN THE WINTER WHEN IT ON FULL MODE AND WHEN YOU LIVE NEAR NEIGHBOURS AND ARE ON THE GAS
MAIN IT IS MADNESS – THEY SAY THAT CONVERSATION IS 60 DECIBALS AND THESE FANS ARE JUST UNDER THAT FIGURE – WELL IN THE DEAD OF NIGHT YOU WOULD BE ABLE TO HEAR A CONVERSATION FROM 1 METRE AWAY AND IT WOULD MOT BE ONGOING ALL NIGHT LIKE THESE FANS NOISE TRAVELS AND IS MAGNIFIED AT NIGHT
AND THEY WILL BECOME THE LATEST NOISE NUISANCE
Hi
A pub about 20 metres from my house has a ASHP. It produces a low frequency hum which causes a resonance in my house which penetrating. You have been warned!
Can I connect a gas fired combi boiler to my air source heat pump circuit to give the heating/hot water a boost in the winter
Hi Ryan,
You would need to get a dual coil hot water tank, so it can handle the feed from the ASHP and the boiler. Also you are going to need a system or regular boiler (i.e. with a hot water tank).
Hi – Somebody mentioned a Perspex lean-to to increase the warm air available and you suggested that the problem then would be the cooling of the air inside this structure but what about if this was a glazed structure with openings designed to allow cold air to sink and be removed and large higher openings for new air to be pulled in? Even though draughty this would still be significantly warmer with even weak sunshine – I know this from my polytunnel which is completely ventilated both ends but very warm even on very cold days. Many thanks
My dimplex air source heat pump sits directly out side my bedroom window(I am in a bungalow) it does not disturb me day or night. It was set on rubber to prevent vibrations being transmitted. It is far quieter than my old Worcester Bosh oil combi boiler!
I’ve never known such a useless system as this. Still waiting for some heat, perhaps it will materialize by next summer. Trouble is I need it now. The system is indifferent to inputs on the wall mounted thermostat display, and the panel on the boiler is absolutely moronic and has nothing to do with the useless instructions. I WOULD give it to my worst enemy gift wrapped. Absolutely fed-up. Don’t get one.
I am in the process of gutting s house and am wondering the best heating mechanism. I was keen for a biomass boiler but the digression in the RHI has led me to think an air source heat pump may be the way forward, although I am getting mixed reviews in the comments here. Have you got any advice. The property is 4 bedroom mid terrace. Thanks!
Hi
I intend to install an air source heat pump
Is it posible to install the outdoor unit in a garage as I live very near the sea and am woried obout corrosion
The garage is quite large and very airy
Thanks
Kenny
We installed a ASHP a year ago and its an expensive waste of money – stick with a gas boiler if you have the option. We used an Ecodan 14KW unit
Hi Simon, we get a lot of interest for air source heat pumps and once people are used to the technology they tend to be very happy. They are only really going to be viable though where the home is very well insulated. On older cavity wall properties (where the amount of insulation that can be added is limited by the width of the cavity) then Air source heat pumps aren’t viable unless the cavity wall insulation is supplemented with internal / external solid wall insulation. Likewise for older solid wall properties – as they are, air source heat pumps aren’t suitable, but provided 100mm + of insulation is added to them then suddenly the heat pumps do become viable. This is basically because they produce water at far lower temperatures than traditional boilers, so you really do need to minimise heat loss from the home.
My outside unit starts up quietly and runs rather smoothly, but it makes a noticeable, high pitched noise at the end of a cycle which I find unnecessarily loud and disturbing. Is this normal? I asked the installer who said it was, but he’s about as trustworthy as an insurance salesman. Any experience with this?
Hi David, some people do complain of noise with their air source heat pump when they are running, but normally it is a consistent noise throughout the heating cycle – in colder weather they do need to work harder though so expect slightly more noise. If you have a strange noise at the end of the cycle and you don’t trust your air source heat pump installer then our advice would be to call the manufacturer of the unit directly and they should be able to advise.
I believe your comments to be misleading. We are plagued by a neighbour’s ASHP within a baffle box and with a bare 1m from the fence. Our bedroom and living room windows are within 5m of the ASHP. There is a limit of 37DbAs permitted on this installation but it is usually run at over 40DbAs. As far as can find out NOBODY has mentioned the noise and effect of the compressor: the constant low pulsating hum. ASHP run 24 hours a day. These devices are NOT neighbour friendly and they are NOT as quiet as manufacturers maintain. I question whether they are at all suitable in Scotland in areas where the average temperature is below 7 degrees. I have spoken to many people who have such systems and almost without exception they complain about noise and all bemoan the fact that they are so expensive to run – definitely not meeting expectation. Local councils and others appear to be putting their heads in the sand. They do not wish to face reality and noise pollution but are seduced by the idea of being ‘green’. Apparently the technology is not as green as we are led to believe as it uses so much electricity. Isn’t it time for the real truth of these devices to be published?
Napier University has done a study on noise from ASHP “EE0214 Acoustic Noise Measurements of Air Source Heat Pumps”, they found most pumps exceed the manufacturer’s stated sound energy level, and some greatly exceeded it (some near 60dBA) once account was taken of tonal sound – the element most likely to cause complaint. Jurgen Bonin in his German book “Heat Pump Planning Handbook” does not regard ASHP as suitable for dense urban housing as the noise pollution is sufficient to cause neighbour disputes. He also discusses the effect on a neighbourhood of having several ASHPs in operation, which predictably worsens the noise situation. ASHP installations in anything less than passivhaus standard dwellings with UFH is a mugs game as the real world COP won’t be adequate for the system to pay for itself, the noise emissions will be a continuous nuisance and the carbon benefit will be minimal owing to high electricity usage. ASHP and the Govt incentives look increasingly like a repeat of the rush to diesel in passenger cars.
Hi Alison,
I’m not in a position to comment on the Db level of the installation in question, but I can with regard energy efficiency. Heat pumps will work at temperatures as low as -15 degrees and their efficiency really does depend on the home they have been installed in. We do sometimes see heat pumps installed in homes that are unsuitable, and as a result end up costing the owner a lot more than another form of heating.
Homes with ASHPs need to be extremely well insulated, with wall insulation up to at least modern building regulations, as well as excellent loft insulation, windows and draught proofing. Installing an ASHP in an old solid wall property that has not been retrofitted will prove very costly to run, because the pump has to work much harder to get the home up to temperature – the running temp of a ASHP is much lower than an average boiler, so the ability of the home to retain heat is critical.
Noise pollution is the killer negative. One man’s paltry saving, a hotly resented intrusion for every neighbour.
We have had a heat pump for over a year now and never have one again. It’s noisy, rubbish for radiators and takes so long to heat the UFH compared to the boiler. Not worth the time and effort of installation. A modern gas boiler (if that’s an option for you) is head and shoulders the way to go.
gas is far superior – they are noisy and run almost continuous – the noise seems to be low frequency through the walls. gas any time. plus you are never warm and hot water warm without topping us from immersion
I have a Heatking air source which was made by TEV in yorkshire and it has been crap. It has broken down countless times and now the very short 2 year warranty (considering they claim they will last 20 years plus) is over they dont want to know. I feel sorry for my neighbours as it sounds like a freight train towing bean cans! It is more efficient than an immersion, but then what isn’t! We don’t have mains gas so had to look for a plan b – if this sounds like you get an oil boiler. You will have spare money in the end, almost limitless companies who can fix and maintain it and piping hot water – I have forgotten what all of these are like! We also fitted a biomass as a backup – steer just as clear of these! Difficult to get parts, they still should be serviced regularly and in the last 3 years the pellet price has doubled!! My costs are approx. (using just one source per day) pellets £10, immersion heater 6kw total – £12 or air source £7.00 – obviously when using pellets I also use some electric during the day.
can anyone explain this simple question,the Panasonic air source heating system we have had fitted now for the past six months heats enough hot water to fill the bath,yet once the bath is filled the radiators go cold and it takes roughly an hour and a half to get the heat ( very poor heat i must add ) back in to the radiators,are we doing some thing wrong ??
any help would be appreciated
thanks for your time,keith.
Whilst I am not familiar with a Panasonic system, Mitsubishi and others will be similar, When you run the bath, and the water becomes cool in the holding tank, the system switches over to heating the water, and the radiators will not be heated for a while since with many systems both will not run together.
What you should be able to do is reduce the time the hot water heating is turned on to say 20 minutes then radiator heating can be set to resume for say 40 minutes, this could be repeated for the next hour.
If the property is well insulated for the radiators not to work for a short period should not be noticed. Also you should be able to use the immersion heater to heat the water if needed.
It is a characteristic of the Heat Pump system that the radiators do not get very hot, and this is why on installation of a heat pump system some radiators may need to be increased in size.
You may need to contact the supplier or manufacturer if the instructions about how to do things are not clear
Carey Moore
Can you give me ideal size for a hot water cylinder to work with an air source heat pump. To supply 1 bathroom with a bath and showe and 1 ensuite with a shower for potentially 2 adults and 2 children.
Hi Karl – a 250 litre cylinder will be plenty.
Apart from the common heat pumps on the market there is also the thermodynamic air source type which is a third of the cost of normal air source and a lot less to run and far easier to install, it also produces hot water and is retro fitted to any wet central heating system
can i use an air source heat pump in tandem with a combi boiler
Hi SD, it can – you just needs a hot water tank with a dual coil – so the tank can receive hot water from two different sources. It is worth mentioning though that if you are looking to take advantage of the renewable heat incentive, if you keep both your boiler and the ASHP, you ASHP usage will be metered, so your payments will be significantly lower (than if they are deemed – i.e. you just have a ASHP as the sole source of heat / hot water).
We have this system and very happy but would like the radiators in the bathrooms changed to a towel hanging style . Would this affect the system?
Hi Sue,
It shouldn’t be a problem at all.
I know there is a unit outside for a air source heat pump but what size is the boiler that gets installed indoor for a standard two bedroom house please?
Hi Josie,
Normally you would just have a hot water tank in your home – which varies in size depending on how much hot water you are going to require! You can get very small tanks, but if you try to have multiple showers / baths in quick succession, those washing later will have to do so in cold water!
If and if the COP isn’t 1:1 or 1:2 in freezing weather then a guarantee that it will save money compared to oil heating or money back guarantee.
These systems performed terribly in energy trust trials, manufacturers and installers allowed to fine tune with disappointing results.
The only saving seems to be vapourware or a money back guarantee would be offered by installers.
we bought an Airsource heat pump 2 years ago and would not recommend it if your on gas. Mitsubishi are meant to be the quietest but they still make noise that wakes me up in the night. our electricy bill is massive and it takes agest for the UFH to heat up when it gets really cold. so we come down to a cold kitchen. Stick with gas. maintenance is also expensive.
Building a new house! Putting underfloor heating in but dont if i should use an air source heat pump or just an oil boiler! Getting miXed reports on air source heat pumps!
Hi
I had an air source heat pump system installed in Oct 2015 in the North of Scotland and Is connected to 11 Dimplex Smart Rads for room heating and also to the DHW. We have been having the problem of when the DHW programme is selected water is still somehow getting to the rads and hence heating the room. I and the installer thought this was possibly to do with the 3 way valve ( ESME valve I think it is called, which operates and blocks off either the water to the room or to the DHW, depending what is programmed. However this was checked over yesterday while I was there and it seems to be working correctly. So the installers seem baffled and are now suggesting that they will run a line from the DHW return to the ASHP unit and put a check valve on it and this should/could solve the problem .
I am afraid I do not have 100% faith in our installers after a few issues we have had with them since installation, and I would really like a second opinion form another reputable ASHP installer, assuming they would be happy to share their knowledge. We think doing what they propose would not really solve the existing problem, but merely plaster over it. Do you have any thoughts on this and have you had any experience of, or heard of any such problems with other ASHP systems. Maybe I am worrying too much about this and should just let them get on with their fix, but when you have shelled out a lot of money for an heating system I think it is reasonable to ensure it is working absolutely spot on.
Our Air heater is high onthe wall – does it make any difference if we put it lower, beneath a window like a conventional radiator. We only use it for heating not cooling. Thanks.
Hi, I currently have oil central heating but I am interested in installing an . air source heat pump. I have happy with the concept of how they work and their higher levels of efficiency. I guess my concern is the additional cost of changing the radiators to bigger versions so they can still keep our house nice and warm. I understand that since the heat pump produces hot water at a slightly cooler temperature than traditional heating systems you need bigger radiators to ensure rooms still get heated to the same temperature. How big (as a percentage) do we need increase the radiators? 150%? 110%? Obviously if it is just marginal, I will look to stick with what we have got!
I have an air source heat pump as well as solar panels in a south facing position…in order to reduce my electricity costs which are very much needed due to disabilities …(a need for hot water via a bath) I need to connect my hot water tank to my solar energy…I know this is possible and tank and solar equipment is placed in my loft close together so it should be easy to pass the electrics of both together …can you advise me A.S.A.P.
Hi Teresa, you need a solar divertor such as the Apollo Gem – https://www.theecostore.co.uk/eco-store/apollo-gem-compact-wireless/
These are really clever bits of kit that basically constantly measure how much electricity your solar system is producing. As soon as the solar system is producing more electricity than is being used in the house, it then diverts the extra to the hot water tank via the immersion unit.
This helps prevent electricity being exported back to the grid and helps ensure you use the maximum amount of electricity you can. It is worth mentioning that if the hot water tank is already fully heated, then electricity will still be exported since it needs to go somewhere, but my sister has one of these fitted with her solar system and they don’t pay for and heating between the months of April and October! A very clever bit of kit the Apollo Gem!
Hi, we moved into a house 6 weeks ago with a Daikin Altherma air-to-water heating and water system. We are finding it so very expensive to run and nobody to advise us how to programme it to run as cost efficiently as possible. We have the manual but it isn’t easy to follow! We have the heating running on the weather dependant setting. If we run it in quiet mode too is it cheaper or more expensive …ie do the internal heaters come on to try to get the water up to temperature? Please can anyone help?
Hi Valerie – we don’t know much about this specific system I’m afraid. Would recommend getting in touch with the manufacturer!
We are thinking of instaling an ASHP with UFH in a stone house which is nowhere near mains gas. The house was essentially a shell and we will have high quality double glazed timber windows and a beam and block floor upstairs. We have already had a warm roof fitted. I am not clear from what I have read whether this techology will be suitable. We do not intend to insulate the very thick (40cm?) granite walls.
We are about to have Air Sourse installed into our new build and are currently thinking about towel rails in the bathrooms, can these be run off air source alone or would they be duel fuel and require an element? If powered by air source alone would it be efficient in costs running them if had a thermostatic controller on each one? Thanks
We have a 14KW Vokera ASHP running underfloor heating and then two upper floors with oversized rads. the catch is when it is cold the upper floors just don’t heat up adequately whilst if anything the ground floor gets a bit too warm. We’ve had the plumbers in a few times now but are now losing faith/patience. Could you advise who I could engage to provide an independent report on the adequacy of the system / installation please as I’m not content to live with it as is? I’m in Norfolk if that helps.
I think An air source heat pump does make some noise when operating, as both a fan and a compressor will be in motion. The air source heat pump emits low temperatures but on a consistent basis.
How big are the actual air source heat pump units? I know it will depend slightly on how big a space it needs to service, but I need to know whether it is feasible to squeeze one under a window in the garden. The house has 3 bedrooms and 7 radiators in total, and it is mid terrace (if that provides a view on how big the heat pump needs to be!)
An air source heat pump (ASHP) works by transferring heat absorbed from the outside air to an indoor space, such as a home or an office via the wet central heating systems to heat radiators and provide domestic hot water. Heat pumps work similarly to a refrigerator: they absorb heat and transfer it to another medium.
We live in a large 4 double bedroom semidetached house. We already have installed 16 photovoltaic panels and a thermal solar panel. The latter provides warmed water to our gas combi boiler to reduce the amount of gas needed to heat water for washing, showers etc. . This has reduced our gas bill by about 25%. My question is regarding the possibility of an air to water system supplementing the existing combi boiler for heating our radiators. Is this possible and is it worth it in terms of paying back the outlay?
Hi Vince – the issue with air source heat pumps used to create the hot water for your heating is that typically when your heating is required, they run relatively inefficiently.
They are great at producing hot water during the summer (sometimes 400% efficient) but during the winter, the compressor needs to work much harder to drive the temperature up to something that is usable.
Basicallt – I would probably leave it!
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