It is clear from Government policy, that they are intent on pushing electric heating in homes in the UK. This is despite 85% of us using gas central heating systems to provide the heating for our homes as well as hot water.
The Government is looking to ensure that from 2025, new build properties are not allowed to be built with gas central heating systems. They are instead favouring ‘green’ alternatives like air source heat pumps. On the face of it, it is not such a bad idea, as homes will no longer be burning gas to produce hot water for heating and cleaning – so homes will no longer be producing the carbon dioxide associated with burning fossil fuels which is thought to contribute to climate change.
For us though, there are two major issues.
Efficiency of ASHPs is much lower during Winter
The first is the efficiency of air source heat pumps. The Government feels heat pumps are game changing technologies as they are highly efficient – at times converting 1 unit of electricity into 4 or 5 units of useful heat (so 400 or 500% efficiency), while a gas boiler might be somewhere around 90 – 95% efficient.
On the face of it, that makes it look a no brainer. A very efficient heating system that produces no carbon dioxide. The issue is that the efficiency numbers often cited in the media are not annualised figures (i.e. an average efficiency over the course of a year). They are cherry picking the peak efficiency – which occurs when the air temperature is in excess of 20 degrees.
Air source heat pumps work by taking latent heat out the air, and transferring this into a refrigeration coolant. The coolant is then compressed using an electrical compressor which drives the temperature up, and then a heat exchanger takes the heat from the coolant and transfers it to the hot water within a heating system. Regardless of the air temperature outside of the property, the coolant typically can get to the temperature required to run a heating system – but it just takes a load more electricity as the compressor needs to work that much harder when the weather is cooler.
It is true there is some heat in the air even in extremely low temperatures, however in order to drive the temperature of the coolant up to a useful level, the compressor needs to work harder – and remember the compressor works on electricity. This brings the efficiency right down potentially to 150% efficiency. So, while in the summer, efficiency of the heat pump could well be in excess of 500% (i.e. one unit of electricity produces 5 units of useful heat), this is certainly not the case when the temperature outside is hovering around zero.
Now if you think of the times of year when you typically run a heating system, it is during the colder winter months. This means that when the weather is cooler, the compressor works harder, and your heat pump will be what we often describe as an electricity vampire.
What we are saying is that when you need the heating, air source heat pumps are working at their least efficient.
As of 16th March, gas and electricity prices are at unprecedented levels.
The cost of a unit of gas is approximately 7.5 pence per kWh.
The cost of a unit of electricity is approximately 28 pence per kWh
But typically the ratio has stayed the same even when prices were much lower – a unit of electricity is approximately 4 times the price of a unit of gas.
If you gas boiler is running at 95% efficiency, it is going to cost you right now about £0.07 per unit of useful heat.
In the winter, when the air source heat pump could be running at 150% efficiency, it is going to cost you £0.19 per unit of useful heat.
So no emissions in the home, but more than twice as expensive to run!
ASHPs are powered by electricity that may still come from burning gas
The other issue with electric heating systems is that while they produce no in home emissions, most of our power still comes from gas power plants. So, it is likely that gas was burnt to produce the electricity needed to run the air source heat pump anyway!
Obviously there has been huge investment into renewables like wind turbines, but if the wind doesn’t blow, much of our power still comes from fossil fuels.
I think there are a few points worth caveating though. Firstly, ground source heat pumps are a different story. They have a very similar efficiency all year round – approx. 450%. However, they are extremely expensive to install.
If you do go for a heat pump, it does infer that your house is sufficiently insulated (their working temperatures are far lower than gas boilers), so that in itself will see you have lower energy bills that an uninsulated equivalent property.
HI GreenAge
Just want to say thanks for keeping us up to date about green initiatives but i think you are missing the point of the heat pump technology. They are not meant to be cheaper, just greener. They make sense for people with solar installations with excess power. I have a system with 8kwh average output and use around 3kwh. It would make sense to use the 5kwh of spare power to run a heatpump but I’m happy for it to go to someone else’s smartphone if it saves gas and coal doing the job.
I think heat pumps should be priority 3 for the government schemes, 1 being solar panels for homes and 2 being electric cars.
They are coming but we need the green supply before we increase the demand.
Hello, just reading the air source heating blog and i totally agree with the loss in capacity when it gets cold outside. Useless. I have discovered a new heat pump class I call the latent source heat pump. It does not need an outdoor unit to function thus no loss in capacity. I am promoting here hy-save.net
Solar panels in the UK? That seems like a total waste. Considering that there are only so many solar panels that can be manufactured at a given time, surely it is better for the earth if they are located in the places with the most consistent sunny weather?
What the government should focus on is wind power, because we DO have consistent wind, especially over the North Sea …
And electric cars are cool, but they are not truly an answer.
More people need to use public transit…
Focus on both. Manufacturing expands to meet demand.
Most boilers are around 24kw
So one hour of gas heating is 7p x 24 = £1.68
Air source geat pump system runs at 3kw , so 28p x 3 = 84p
Soooo, that’s both at 100% efficiency.
Please, if you are going to do articles like this, please do give all the information.
Oh dear,you don’t know much about boilers do you
You need to compare the total kWh
3kw hours of ASHP is NOT going to heat the average UK home
You shoudl really only critisise the article if you properly understand the subject. I dont know that much about it but I do know that it is very rare for a gas boiler to run continuiously. They switch on and off as required, or with some more modern boilers they moudulate their output so that a 24kW boiler is running at a lower output most of the time. I fitted a Honeywell evohome system to a boiler in our big house and that used a tpi system where the evohome brain calculated what percentage of the max output was required at the time. Then the boiler switched on 6 times per hour for the percentage of 10 mins equal to the proportion of max capacity required – except in the coldest weather it was running for much less than 10 mins each time it came on.
Hello Me
Your assumptions miss the point a bit, too. Gas central heating can be put on for 1-2 hours in the morning then 1-2 hours in the evening, so taking worst case at 24 kWh gas boiler consumption over 4 hours/day then this equates to 96 kWh/day for heating at 7p/kWh = £6.72 paid for gas./day
A comparible sized heat pump drawing 3 kWh needs to run all day during the colder months, may not heat the house to the desired temp if only running at CoP 1.5 (4.5 kWh heat supplied) and needs to shut down to defrost during the coldest periods of the day so often needs a backup or will let the house go cold. 3 kWh x 24 hrs x 28p = £20.16 electrcity/day provided no fall back temp at night is set (if the heat pump does indeed reach full house temp).
Until gas prices reach electricity prices like James says below, there’s not much point for older draughty home, but what would be the chance that gas prices will reach electricity prices in the future if the government introduces a carbon tax and removes fossil fuel subsidies? Then it would absolutely make sense, but we’ll all be paying sky high energy prices well in to the future unless we can afford a large enough solar array installation and huge insulation upgrades and high heat pump installation costs simultaneously.
Also you can’t insulate a lot of the draughy old homes – I looked into it and it turns out that wattle and daub homes like mine rot from the inside out if you do that (since the ‘draughts’ are how the moisture gets out of them and without that the wood starts to rot. Really not sure what the answer is for older homes short of knocking them down and starting again.
stick in an MVHR and insulate your house,
a typical UK home requires 6-8kW for heating, the boiler won’t run at 24kW most of the time (otherwise you would need a heatpump of 8kW to match assuming a COP of 3) so your figure for it is really 7px8=56p or cheaper than the heatpump. But, as others have said, heatpumps aren’t about cost but being green (if the soure of the eletricity is).
Nah, don’t worry about the climate, count the cost!
Missing the point really – Use of electric heating such as via heat pumps is not about saving money (although it does) its about CO2 emissions, as time goes on more electricity is going to come from renewables or nuclear. So the argument about electricity using fossil fuels for its generation is only a short lived one (same argument applies to electric cars) its part of a large plan of change to reduce dependency on fossil fuels and as a side benefit cost and energy security.
Using heat pumps might well push us to insulate our homes better, which is no bad thing!
Hi Brian, I agree to a point – however with any intermittent energy source installed, its capacity needs to be matched with a source that can defo be turned on / off (e.g. Gas power plant). So I would actually say it is pretty relevant. There are also transmission losses to think about – Burning gas in your home is more efficient than using electricity made from gas delivered to your home.
Also the cost of electricity is so much higher than the cost of gas. Until they reach parity then the whole decision is a bit of a no brainer.
Your final point in terms of having to insulate our homes better is absolutely true!!
I’m not sure where you are getting a COP of 150% from. No modern heat pump will perform that poorly. Even in the December cold snap when it was -7C overnight and -1C in the daytime my ASHP was getting 230% efficiency. In typical winter weather like we have now it’s more like 270%.
The climate situation is so serious a threat/opportunity to the current and ridiculous ‘Business As Usual model’ that it requires, nay – demands, different thinking to the profit/financially focussed consumer choice driven one that you seem enthralled by. If we, as you imply, wait until simultaneously cheaper, greener and more convenient options are deployable before any of your readers makes any change and we will worsen the future entirely. Future heating systems users may not have the apparent luxury of choosing between consistent, on-demand energy supplies, particularly if we follow this inertia-mindset advice. I don’t doubt you get hard for nuclear; bollocks to the future, eh? Why not consider removing ‘green’ from the branding. Perhaps replace with ‘money’ whilst you use your platform to suggest to others what is .’no brain’ decision making at TheMoneyAge.co.uk
Thanks for this well written & concise article, it echoes my instinctive musings on the matter.
Nobody is going to run air source heat pumps when it is warm. It seems self evident that getting heat from cold air will require a lot of power, which perhaps could be used more directly. I mean at what point do we just have direct electrical panel heaters instead for example?
I really think widespread adoption of this technology will be a huge mistake. I also worry about people being urged to “upgrade” in their stone built solid wall houses, insulating them but not allowing for ventilation…there are going to be so many moisture problems.
And how constantly will these units have to run when it’s cold? They will be a noise nuisance I’m sure, as are air-con units. They are just as ugly too. Even if all the power used is renewable or nuclear, they could still have negative effects on our standard of living by aesthetics & noise. Huge radiators for example, & complete overhaul of plumbing.
Efficiency & insulation, & maybe running a home a little cooler & using a blanket seem like sensible steps.
An inaccurate article. The consensus of science, world governments and the IPCC state CO2 is causing climate change and an unlivable world
The Government need to start insulation grants again including for solid walls. Evidently there are no bungs forthcoming for them so it won’t happen
Heat Pumps Definitely ARE the answer.
I think your article on the ASHP is a bit disingenuous, The fact that 85% use gas is neither her nor there, we all have to start the journey to stop burning fossil fuels, and move to electric,… clean electric. If we do move to electric, then a large proportion of that can be made with renewable and nuclear. even if oil or gas is burned centrally, it will make up perhaps around (only) 50% of the overall electrical energy suppled to customers. Secondly, even if the heat pump efficiency is (only) 1.5 it is still MUCH better than 0.9 from a well setup gas or oil boiler. So a gas boiler producing 1kWh of energy will burn 1.11kWh of fossil (gas),.. a (1.5 COP) heat pump will use 0.66kWh of electrical energy to produce 1kWh of heat, of which only 50% was fossil, so only using 0.33kWh of fossil. the rest (0.33kWh) was nuclear, wind, solar. Using 1.1kWh or 0.33kWh of fossil to create 1kWh of heat,… which is better? Often at night the UK turns off 50% of our wind generation, as there is no demand for it! Heat pumps could be using this energy.
All of the arguments made here are two dimensional. With 8 Billion people on our planet, all resources are fully stretched. Unless the population reduces, to levels of 40 years ago, about 3.5 billion, then all current energy technologies will prove to be inadequate. We are all now witnessing a step change for life on this planet. Arguing about which domestic heating is best is frankly moronic. Best you all make the most of what you have for now, because it will not be here fir much longer
I totally agree. Britain’s population is 35-40% overpopulated. If the British want a good survivable future them we must reduce the population ASAP.
The thermal efficiency of the gas power station (circa 50%) or the oil and coal power stations (circa 30%) need to be factored in
So the 0.66kWKh of electricity requires 1.32kWh to produce from gas fired power stations
or 1.0kWh if factoring in that 50% of electricity is generated from renewables
We have had an air source heat pump for 3 years; the experience I describe here is specific to our house, and where we live (Cheshire, 150m above sea level). The house is rural, and mains gas isn’t an option. We are 2 people, and the building is a combination of old solid brick walls and new cavity walls in a recent extension. The old part has been clad with 50mm Kingspan insulating panels with a waterproof K-Rend coating, and downstairs the interior has 37mm insulated plasterboard; the new part has cavity wall block insulation. The entire loft has 11 to 12 inches of glass fibre wool. The ASHP/underfloor project was party of a general house renovation, so it is difficult to ‘filter out’ the net effect of the ASHP: there is no doubt that the extra wall insulation has helped a lot.
We use the ASHP to run underfloor heating over 110m2 of the ground floor. The few radiators we have are upstairs, and they are run from a 3 year old Worcester LPG boiler, which also heats our domestic hot water via a highly insulated tank – giving us higher water temperatures than would be available from an ASHP. The only radiators we really use upstairs are bathroom towel rails, although they are switched off in summer; Only when the temps are below zero do we switch on a single bedroom radiator for 2 hours a day. We cook on LPG, and a 2200L tank lasts us over 18 months.
Installation cost for the ASHP was about £16K, but that included £5K for underfloor piping and concrete screed on the ground floor. Plus we chose a German ASHP (Stiebel-Eltron). Cheaper ones are definitely available.
The total cost of electricity for the first year was around £1000; that includes lights, electric cooker, TV, computer, hair dryer, all the usual stuff. Because we registered for RHI, we got about £980 of that back in the first year. We will continue getting RHI payments up to 10 years from the initial installation; it’s index linked, so is currently paying us about £1100 a year.
Clearly, our electricity bill is about to seriously increase; my guess is about £2.5K. That’s what we used to spend when the place was heated by an ancient LPG boiler and radiators, plus an oil fired range in the kitchen which cost us £600+ a year to run.
Positives from the experience: the house feels very comfortable, with the heat distributed evenly – no cold spots (and more wall space). In years 1 and 2, we didn’t really have an electricity bill due to the RHI payment. Temperatures down to -4C have not been a problem.
Negatives: when the wind blows hard in winter (we live on a hill), the new extension (with it’s modern insulated cavity walls) cools down and makes the ASHP work much harder. This isn’t a failure of the heat pump, but because the builders did a poor job. Wind enters the roof cavity via the normal gaps between the tiles and overlaps in the felt. Then it blows down between the cavity walls AND down behind the ‘dot and dab’ plaster boards, which weren’t correctly sealed at the top. So you get a cool breeze blowing out of the electric sockets, from behind the kitchen units (no skirting board), wherever you drill a hole in the wall. I have talked to other people and this is a common problem – modern building standards and practices in this country are frequently poor. It is presently being fixed, but there are some bits of the wall that are impossible to get to, so we will see what happens this winter.
The lesson from this is if you want an ASHP to run efficiently, make really sure the house is draughtproof and well insulated. When it’s not windy, the ASHP has no problems whatsoever, and will remain competitive with LPG in terms of running costs,
If I could do it all again, I would get a ground source heat pump and save money somewhere else, and I would use it to run the upstairs radiators as well. And I’d supervise the plasterers properly! I’d still keep LPG for the gas hob though. Yes, it isn’t very green, but if you live in the country, you need to have a fallback when there’s a power cut (every winter since we’ve lived here). And we’re on a hill with some space, so I would love to install a wind generator.
What else? Well, despite some comments above re. external insulation leading to condensation and dampness, the building feels very dry; maybe that’s an effect of underfloor heating. Dampness is definitely not a problem. The ASHP obviously isn’t silent, but it is barely audible from indoors; you have to put your ear to the wall to hear it.
I’m very aware that I’ve described something that most people will never afford. However, if you can cope with rooms being 3 inches smaller between the walls, insulated interior plasterboard (and a well insulated loft) is a brilliant (and cheap) investment; solid walls will feel a lot warmer, your house will be cheaper to heat. I know people who have told me “we could never afford that”. Fair enough. I drive a 14 year old car, bought second hand. A couple of folk with whom I’ve discussed the ASHP project told me they thought it sounded expensive (they were right). But one drives an Audi A8, the other a Jaguar SUV. Those cars will depreciate by hundreds of pounds per month. It all depends on your priorities.
Of course, what we really need is a government that understands the long term problem, and that isn’t happening right now. People need real help and motivation to improve their houses, but the government doesn’t believe in ‘handouts’. I’d say helping to avoid climate apocalypse isn’t a handout, it’s an investment. A lot of folk believe that the scientists are going to be able to fix it, and I really don’t think that’ll happen. If the East Antarctic ice shelf melts in it’s entirety (possible within ten or fifteen generations, given the current tipping points we’ve reached), we’re looking at 52 metres of sea level rise. That’s 165 feet. And that doesn’t count Greenland and the West Antarctic ice shelf (which will melt first), the collapsing Amazon ecosystem, the melting mountain glaciers etc. etc. Several billion people will eventually forced to move: it will make the current UK immigrant issues look like a stroll in the park. If you have children, you owe it to yourselves to make the effort. Vote for a party that actually cares about the environment!
Sorry, bit of a rant there, but it’s all true.
JM
Not that I understand the workings of a ASHP, but my neighbours is driving me crazy. Constant noise of compressors in the water system, low hum and I think mains hum. Had 4 hours sleep last night this is a constant. I can hear the ‘noise’ in the garden. Environmental Health can’nt pick up this ‘noise’ with their equipment. So I had a private assessment done. This did pick up sound. They measured in Hz. The Environmental Health measured in dB. The ‘noise’ is affecting my hearing – tinnitus going crazy and a constant headache. The make of ASHP a Viessman size I don’t Know. I’m at my wits end with this ‘noise’ The fan in the unit is not going round so that’s what makes me think it’s the water heating that’s the problem. The neighbour is not approachable, and does know the ‘noise’ is annoying me. What I would like to know is what is making this ‘noise’ and why. Any help would be welcome. I know nothing of these ASHP but have read of this on the web but nobody seems to come up with an answer.
That sounds like something’s not right at all. I had an ASHP installed a few months ago and it’s extremely quiet. The fan unit is right under our kitchen window and you can’t hear it even with the window open. The exhaust on the boiler next door is louder!
What brand of ASHP to you have installed? Mine is Grant and pretty loud as Penny mentioned above and drives me and my misuses crazy it suppose to be “Quiet Mark” approved but it is heard in our living room at every evening it operates. It was measured with dB meter and it was approx 61dB which is not comfortable.
Not exactly. Ground source heat pumps are not horribly expensive to install. They do cost more to drill the bores but once drilled they will be there forever. An investment not a cost. Ground arrays can only be laid in large areas of open ground which limits them but open water sources can be exploited. Your existing gas or oil boiler will need replacing but your bore will not in a reasonable lifetime. As an investment a heat pump is going to add to the resale value of your property and attract tenants.
As most of our carbon production is the need for home heating should all Scandinavians move to North Africa, ? Their hydroelectric power could be transmitted to Holland.
Logs are popular as renewable fuel but it takes 30 years to get to log size. Fine if you are prepared to wait. Trees are wonderful and release our essential Oxygen from the air and take out the carbon dioxide. But that is all put back when you burn them. Studies have shown that even covering the earth with trees wouldn’t be an answer, because trees die and eventually release back all the CO2 they have absorbed.
Nuclear power is low in carbon and Uranium sources are believed to be plenty and unlike gas and oil are less subject to better regional control.
Gas and oil are considered fire hazards by insurance companies and increase the premium for house insurance. The dreadful fires and deaths that are reported are witness to their dangers. Nuclear power has shown itself to be reliable and providing that you don’t build stations in an earthquake zone, more sustainable.
Air source heat pumps may not be as cheap to run as suggested by manufacturers but they are a step in the right direction, Ground source heat pumps are even better and where feasible both worth the effort for the long term.
Wow. This quote shows the perspective of the writer in 2022! . ‘ burning fossil fuels which is thought to contribute to climate change.’ It does contribute to climate change and we’re all in the s**t for it. Make sure you read multiple sources before you make your own decisions. Heat Pumps are a powerful tool in a large number of situations.
I totally agree with your views on heat pumps, as an engineer with experience of a/c and heat pump technology. One other point that is often forgotten is the amount of energy available from electricity in the home, for example I have warm air gas heating which is very efficient, we only turn the thermostat up if it’s feeling a bit chilly, takes only 10 minutes to warm the house, however with electric heating of any sort you do not have the energy available to heat quickly, so you have to predict if it’s going to be cold or heat the house when you are not there so it’s warm when you get home, if you are using underfloor heating there is a bigger issue, what happens if you heat your floor and then find you don’t need the heat as the weather has warmed up, well what you do is open the window and let it out. Ask any user of storage heaters, my parents had underfloor electric heating, heated up over night on cheap electric, totally uncontrollable and wasteful, and on cold days you would run out and have to boost with full price electric (bills of £100 a week were not uncommon 2oyrs ago)
So, maybe heat pumps will be more efficient than old storage heaters but better insulation is essential, this is expensive and there is a carbon footprint in producing it, but if your getting heat pumps fitted in an older property then expect big (i mean big) electric bills whilst the cost of electricity is as high as it is at present. I have two air to air heat pumps, one to heat an extension which doesn’t get the warm air due to a design cock up by the builder and we have one in the conservatory, we now don’t use these very often at all now the energy prices have gone up so much and we don’t use the hot tub either, we were using 7000 units a year plus what we use from the solar panels.
Heat pumps are fine for modern, highly insulated houses, but their installation is a colossal waste of money, time and carbon on older properties. It is outrageous that this is being pushed as a one solution fits all policy.
The real green answer for these older, usually rural properties will be synthetic or bio-fuels which will replace conventional kerosene (this is already happening in the aviation industry) in oil-fired boilers, This will not require expensive retrofitting of houses and heating systems, and the convenience of implementation will trump ASHPs in these situations.
Sorry to hear you are having a noise problem. I know it can be an issue as I have experienced it myself. Its a problem not just with heat pumps but any electrical equipment with motors and moving parts. A modern heat pump in good repair should be almost silent. Biggest source of noise is usually the air pushed out by the fan. It is possible to install a hush hood that will block out a lot of the noise but this would be a special build as it needs to be designed and built specifically for the installation in question or it can affect the heat pumps operation. Though A well designed hood could actually improve the heat pumps efficiency by improving the airflow. If the fan is not running then the heat pump is not working though there may be a circulation pump that keeps running all the time it would be very unusual for this to be audible at all. It is also possible that the unit has been improperly mounted and is attached to a wall that is picking up vibration and acting like a sounding board. What it boils down to is a technical problem that will have a solution.
hi my two next door neighbor’s have had air-source heat pumps installed recently, one of them being just a few yards from my kitchen windows.
They are both blowing out stale unventilated and unpleasant with respect, bedrooms bo smelly sock smells.
These smells lingar about my garden and often waft through my kitchen windows as we are quite closed in by trees and shrubs not allowing the smells to blow away.
Accession ally while having breakfast enjoying some breeze through the windows, wafting in with that breeze comes the distinct smell of freshly dumped toilet, its so vile i nearly vomit.
I am always waking up twice some times three times in the middle of the nite by the mechanical noises these ASHP make.
I am unable to sit in this close nit garden for this noise and unpleasant smells distresses me.
i have done some research and found these ASHP have health issues,
one of the most common serious health issue is mould growth inside the pump that can lead to all sorts of health issues from throat irritation to cronic lung diseases.
I have asbestosis with lung deseases,
i had both eardrums perferated at birth, medically operated on by Royal Army medical core, i have very sensitive hearing and this noise hurts.
I am anxious about the unpleasant smells given off by these insulation, Doing some research found the air in houses where people don’t go out much, like my neighbors who are old is more toxic rhan the out side air, that i must inhale
nice yeah.
i am begining my complaint to the housing association who installed them to have them removed.
Would you please inform me of any legality rites i have to have these air source heat pumps removed to
robbin.longstride@gmail .com
thank you
staySafe
robbin
That doesn’t sound like heat pumps you are talking about! Heat pumps don’t pump air from inside so they can’t be responsible for the smell. They pass outdoor air over a heat exchanger so the air just goes from outdoors at the back of the unit to outdoors at the front of the unit. There is no opportunity to pick up any snells from indoors because the air never comes indoors.
What you are describing sounds like either extractor fan vents or some kind of MHVR ventilation system, not a heat pump.
Just as the all electric car has problems that can be reduced with a hybrid system, would it not make economic and environmental sense at this early stage of change to have a hybrid home heating system? During the coldest periods the gas boiler would take over at other times the heating would be from air source heating. Since most households already have a gas boiler this would only involve the installation of air heat exchanger. Efficiency of the air heat exchanger would average out at around 300%, and operate for over 75% of the year. There would be a substantial reduction of CO2 produced by the household and the CO2 produced by the fossil fuel power stations.
Hi Michael! In 2023, air source heat pumps using R290 refrigerant (Vaillant aroTHERM plus; Panasonic Aquarea L Series) can provide heating and hot water year round. More efficient in summer, less so in winter, but still effective. Hybrid isn’t required anymore.
[hybrid also suffers from twice the capital investment and maintenance]
This will be why they are so popular in *checks notes* Finland. Oh.
Air to air is, not air to water…and in highly insulated, triple glazed, open plan homes. You’re just a repeater.
This is a seriously misleading article. We have a very basic ASHP, it is currently 0ºC outside and the efficiency is running at 350%. Figures of 150% will be where the ASHP has not been installed by a knowledgeable installer.
me too. works really well . last February -9c outside. Toasty inside.
a COP of 150% is far lower than modern air source heat pumps can and regularly do achieve. Modern units would generally have a MINIMUM COP of about 250% and will have an average COP for the whole year of 300 – 500% when installed correctly. This makes them much more efficient than gas boilers which regularly achieve an average efficiency of 85% rather than the 95% stated in your article.
Electricity in the UK is still partly supplied by gas fired power stations, however with a COP 350% and a power plant efficiency of 50% you still get more useful heat delivered to your house by turning the gas into electricity to be used in a heat pump than you would by directly using a gas boiler. In fact you get twice as much!
1 unit of natural gas can create 0.85 units of heat in a gas boiler, vs. 2.05 units by burning the same amount of gas to create electricity and then using the electricity in an ASHP
There are loads of really good and well researched articles on this website, however this isn’t one of them.
Question, as stated ASHP are more efficient at higher temperatures then why not site them in an attic. Attics are ventilated via the eaves and the ASHP will be generating heat form the compressor.
Any advantage would be minima and not last longl. It takes a LOT of airflow to extract sufficient heat and your roofspace would get very cold. So cold that the efficiency would drop more than you initially gained