Air source heat pumps in winter: Busting the myth

  • DebF_EONNext's Avatar
    Community Team
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    Hey Community ๐Ÿ‘‹

    Air source heat pumps often get a lot of bad press, one of the most common reasons people are against them that I've heard is "they don't work in the winter" ๐ŸŒจ I'm here to bust this myth!

    Did you know ๐Ÿฆ‰

    Air source heat pumps can pull heat from the air in temperatures as low as -25c โ„

    Some of the coldest countries in Europe have more heat pumps installed than anywhere else in the world! Luckily in the UK we are fortunate to have a warmer climate than some of those countries so it would be rare to reach temperatures as low as -25c.

    Whilst it is true that heat pumps may have to work a little harder in the winter they are designed to run at much more efficient temperatures than a boiler!

    You may be wondering ๐Ÿค”...How does the heat pump work even when it's cold?

    The heat pump contains refrigerant that absorbs heat from the air outside and a heat exchanger.

    Even though the outside air is colder than the air inside it's still warm enough to cause the refrigerant oil to boil up and turn into a gas. The heat pump then compresses this gas to increase the temperature into more usable heat.

    The heat from the refrigerant gas is then transferred to your home via the heat exchanger and circulation pump, the heat is then transferred to your radiators, the heat pump also creates enough heat to charge the water tank too making sure your winter home is warm and cosy!

    @P962c gave us some lovely insight into their experience with air source heat pumps in their thread: Living with an Air Source Heat Pump - 2 years on

    I want to hear your thoughts...have you thought about installing a heat pump? Do you have a heat pump and if so how does it perform in winter? Have you had a similar experience or perhaps your experience been completely different ๐Ÿ•ต๏ธโ€โ™€๏ธ I would love to learn more!
    Last edited by DebF_EONNext; 02-10-23 at 20:46. Reason: formatting
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  • 41 Replies

  • meldrewreborn's Avatar
    Level 91
    @DebF_EONNext

    Weโ€™re all familiar with fridges and freezers. These create a cold space by removing heat and releasing it from the back of the appliance. A heat pump does the same it removes heat from outside the home and delivers it inside. The technology is mature, not new, and in widespread use elsewhere.

    in the UK we have long had a large gas network, originally utilising coal gas, but from the 1970โ€™s natural gas, which became the fuel of choice for heating because of its very significant price advantage, which continues to this day.

    Heat pumps almost exclusively run on electricity, so suffer from using an expensive energy input cost but then are able to produce 3-5 times as much heat output, which makes them almost on a par financially with a conventional gas fired system. The capital costs of switching from a gas boiler to a heat pump system can be significant and not all properties can accommodate the necessary changes. Uncertainty over future running costs, essentially what will be the price of electricity and gas in the future adds to reluctance to adopt heat pump systems.

    There are actually gas powered heat pumps available, which produce running costs much lower than even the best A rated boilers, although rarely promoted in the UK, perhaps because they are still consuming a fossil fuel. Some of us can still remember gas powered fridges from our youth.

    there is much debate over how the UK can deliver net zero policies in which the use of fossil fuels will necessarily have to disappear, while generation of electricity is ramped up perhaps 5 fold compared to today, Nuclear energy, once touted as being so cheap it could be given away is now expensive due to extensive safety measures. Hydro is at or near capacity, while wind and solar have the problem of intermittency, requiring gas power stations to be on call but vastly under utilised. Getting to net zero will inevitably mean more expensive energy costs for us all, so using less through energy saving and insulation will become even more necessary than it is now.

    I am convinced net zero can be achieved, but nobody should be in any doubt that it will require great effort and sacrifices along the way. My generation had to rebuild the country after WW2. Apart from the physical stuff financially it took 50+ years to recover. The effort to reach net zero is of comparable scope in my opinion.
    Current Eon Next and EDF customer, ex Zog and Symbio. Don't think dual fuel saves money and don't like smart meters. Chronologically Gifted. If I offend let me know by private message, but Iโ€™ll continue to express my opinions nonetheless.
  • meldrewreborn's Avatar
    Level 91
    @DebF_EONNext

    I suspect itโ€™s the use of Fahrenheit and centigrade that leads to confusion over heat pump performance at low temperatures. Astronomers use kelvin where absolute zero is minus 273 degrees centigrade. So zero centigrade is 273 kelvin and 20 centigrade is 293 kelvin. What in human terms is cold, is nothing like it in kelvin terms.

    disclaimer: I think the foregoing is correct but I did this many years ago and my memories may have frayed a bit.
  • WizzyWigg's Avatar
    Level 76
    @DebF_EONNext

    Heat pumps will in the future become part of every day life.

    The first priority though in this country is the improvement of insulation in already existing properties, and particularly older ones. New builds are not so much the problem.

    The UK have some of the worst figures for heat lost, certainly compared with countries such as Norway and Germany. Houses in the UK loose, on average, heat 3 times faster than in those countries.

    Interestingly Norway has one of the highest percentage of heat pumps, at around 60%.

    Installing heat pumps into poorly insulated houses is an absolute non starter. Therefore insulation is another cost that needs factoring in along with the pump, possible changes to radiators, plumbing, redecorating, etc etc. These additional factors can make it cost prohibitive for many, even with the government's contribution.

    We will eventually achieve the goal, (It is necessary), but not in the time frame that is designated at the moment.
  • DebF_EONNext's Avatar
    Community Team
    Some good points there @meldrewreborn

    I think you've just explained it right there until the air hits absolute zero there is still heat in the air due to science stuff (way above my head) to do with atoms and molecules moving around (high school physics & chemistry have left the building ๐Ÿ˜†) so there is potential for a heat pump to draw heat in much lower temperatures than we would expect.

    I believe that net zero is achievable no doubt about it but I do think that a lot of this comes down to the government supporting those that don't have the means to explore the solutions offered and more education on the matter. Do I personally think that it will be achieved in the timescale given no I don't but I do believe that we need to try.

    It's interesting you mention it being property dependent @WizzyWigg I was speaking to someone last night about a couple of colleagues both have different set ups one in a period property and the other in newbuild eco home, both have heat pumps but very different experiences.

    I agree about insulation WizzyWigg even older properties can benefit from this in some form or other. It doesn't all have to come down to expensive solutions though things like making sure your door/window seals aren't damaged or worn and adding draught excluders to doors all make a difference and are relatively inexpensive too ๐Ÿ˜Š
    Last edited by DebF_EONNext; 03-10-23 at 11:49. Reason: random letter I on the post!
  • meldrewreborn's Avatar
    Level 91
    @WizzyWigg

    I think the ready availability of relatively cheap gas has resulted in insulation to retain heat being very low down on most people's agenda in the UK.

    Now that gas is likely to be phased out in the coming decades and more expensive fuels replace it, insulation is going up the agenda. I feel rather smug that my home was suitable for cavity wall insulation and I had it done in 1978, so I've enjoyed many subsequent years of lower bills due to my foresight.
  • meldrewreborn's Avatar
    Level 91
    @DebF_EONNext

    Property dependant.

    Tenants can't do insulation jobs -its the landlords responsibility. Purpose built flats will require a heat pump slung on an exterior wall or else very long insulated pipe runs. Not pretty, perhaps noisy, but certainly expensive to install and maintain. A gas boiler is a much easier fitting task.
  • meldrewreborn's Avatar
    Level 91
    I think too many people throw up their arms in horror and look to the government to fund solutions. Of course government money is our money, so we pay either way. There is a viewpoint which says government sets the rules and the market delivers.

    Who is paying now for solar, heat pumps and EV's? A subsidy is there on some of this but essentially its consumers are paying to make the change.

    So imagine if the price of gas goes up steadily year after year (via a carbon tax), green levies are switched from Electricity to gas changing the relative advantage that gas boilers over electric heat pumps, and people will decide for themselves what makes economic/financial sense.
  • WizzyWigg's Avatar
    Level 76
    @WizzyWigg

    I think the ready availability of relatively cheap gas has resulted in insulation to retain heat being very low down on most people's agenda in the UK.

    Now that gas is likely to be phased out in the coming decades and more expensive fuels replace it, insulation is going up the agenda. I feel rather smug that my home was suitable for cavity wall insulation and I had it done in 1978, so I've enjoyed many subsequent years of lower bills due to my foresight.

    I too am very fortunate having cavity wall insulation. I've also changed all windows and external doors to meet with the modern standards. Loft insulation has been doubled.

    I do have an advantage with the house location. It's east/west. Sun in the front in the morning and in the back in the afternoon. Weather dependant of course. Heat from nature's own fusion drive ๐Ÿ˜‰ has got to be the most cost effective.

    Like yourself it made significant reductions in energy consumption.

    I better just say that the majority of the work was done prior to retiring, when I was able to afford it. Foresight is wonderful.

    When it comes to heat pumps forward planning is paramount. Looking at what is required for the thing to work when it is installed and preparing for the inevitable will reduce the pain on the wallet
  • WizzyWigg's Avatar
    Level 76

    I agree about insulation WizzyWigg even older properties can benefit from this in some form or other. It doesn't all have to come down to expensive solutions though things like making sure your door/window seals aren't damaged or worn and adding draught excluders to doors all make a difference and are relatively inexpensive too ๐Ÿ˜Š
    You are spot on. The little things certainly would help with every day reduction in energy consumption, and little or no expenditure. I'm not sure though whether they would make great inroads into creating enough insulation for the effective running of a heat pump.

    I am truthfully going on feedback from friends, family and neighbours. All of which have had varying degrees of success.
    Last edited by WizzyWigg; 03-10-23 at 15:49. Reason: A little more information