The BBC has reported on the main problem with Heat Pumps. I’m glad someone finally has.

Read their article here.

The illusion.


Heat pumps are being heralded as this amazing new saviour come to release us from the Russian enforced iron grip of natural gas – although it has absolutely nothing to do with GeoPolitics or the blatantly obvious economic damage the Russian’s control over our main source of heating fuel has caused – nope, it’s all about climate change… Honest…. In fact heat pumps are so efficient that it has driven the Government to propose a ban on Gas boilers by 2035, or somewhere around then, or by then, no-one is quite sure, so no surprise there then. write about that here

This all sounds amazing right? What are these wondrous little playful beasts that may lessen our energy use burdens and free us from our own environment-destroying ways? The general idea being pushed by “The Powers That Be” right now, is that they take warmth from the air outside, and use it, extremely efficiently, to heat our water inside, thereby doing away with the need for a boiler, which we can now ban outright. They’re up to 3 times more efficient than a gas boiler too so not only are we talking about getting thermal energy from nature and not from burning more fossil fuels, but we can do it at a 3rd of the price too! Yay!


“Let’s go a climate-saving boys!”


Wowzers. It’s a miracle. So much so that Scotland’s First Minister Humza Yousaf has even said he will ban our Scottish friends from selling their homes unless they have heat pumps installed! Well technically it’s if the homes don’t reach a certain airy-fairy EPC standard of C or above, whilst those ratings are being downgraded if they’re not achieved by “green means.” So, all in all, install a heat pump or you ain’t movin…

Absolutely brilliant, both Governments totally smashing it, leading the charge shouting: “let’s go a climate-saving boys!”



The truth.


I shan’t go into details for professional reasons, but I am currently involved in the “refurbishment” of a bunch of let’s say “public buildings” in London. They’ve bought 3 massive air source heat pumps and installed them on the roof of the first of 20 of these buildings. That’s 3, the size of a mini, about 20m from a block of terraced residential homes. Nice one. Yes they can be quiet, but not 3 of that size, next to each other, that close to domestic buildings!

What we have pointed out is that their solar panel array on the rooftop, is filthy. Not only that, but it isn’t even plugged in, and is 15 years old, and has no battery to retain excess. We can no longer conscientiously use the term “refurbish” for projects like this either because let’s face facts, it’s a retrofit, and that now has to conform to PAS2035 “guidelines.” The point being here, is that they had more than enough funds to completely replace the solar array with newer and much more efficient panels, and actually plug them in, with a battery bank.


That’s like not fixing a puncture on a tyre, but instead trying to use a more efficient pump to keep it pumped up with less effort. Pretty foolish if you ask me.


The energy “saving” over time would have been immense compared to the heat pumps, and they would have had enough money left over to go around the buildings with nice and efficient Passivhaus certified draught tape and save 15% of the heat loss easily – old buildings like that lose the majority of their heat through easy-fix losses like that.

The point there being one of “first principles” – there’s literally no point buying and installing expensive equipment to try and “use” less energy when you are losing so much that you use in the first place. That’s like not fixing a puncture on a tyre, but instead trying to use a more efficient pump to keep it pumped up with less effort, and then boasting about the saving in energy… Pretty foolish if you ask me. Also, if you aren’t reducing the amount of energy you lose, it is counter-productive to celebrate that you’re using less in the first place. That’s like having a hole in your pocket and losing a pound coin every hour, but then being pleased that you had to do less work to fill your pockets in the first place – you’re still losing a pound an hour! We’re supposed to be reducing our NEED for energy, not how easily we can produce/provide it for use. How are these people still not getting that!?

Step number one should always be to reduce losses, then step two is improve supply, then step three should be to then improve the efficiency of all the above. The problem with all of this thinking in regards to heat pumps, and the really obvious “let’s jump on the band wagon” mindset of those in positions of authority, or with decision making power, or both, is that it completely misses the important details:


  1. Heat pumps are designed to pre-warm the water that enters your boiler, meaning you use less energy to heat it to the maximum, which shouldn’t really be above 70 degrees, even in the dead of winter. If it is, your building is a sieve and you should start taping up some holes, not installing heat pumps. So, with no gas boiler, you’re not going to get more than maybe 40 degrees to heat your home with, at best, depending on how expensive and efficient your heat pump is – and with people struggling to stay warm right now WITH a gas boiler, you’re pretty much dooming people. It’s actually criminal in my opinion, like how can they ban our primary source of heat with no suitable solution!?
  2. They cost anywhere up to £12,000 to install. Yes, that’s an entire annual income for a low-end, entry-level job. If the average family home spends about £2200 a year on heating, it’s basically 6 years’ entire heating bill. Where is the “saving” exactly?
  3. They are basically fridges in reverse. They use a refrigerant gas that is compressed, (using electricity I might add, and a lot of it,) to increase the pressure of the slightly warm air coming in from outside. That in turn increases the temperature of the air as it moves indoors, because you know, Science. Then, as the air cycles back around outside, it’s allowed to decompress which drops the temperature again, ready to attempt to pick up thermal energy from the 5 degrees of British overnight air for 8 months of the year…
  4. When the temperature gets too low, the unit has to go into defrost mode which means even more electricity usage.



Some honesty. *Shock*


Honestly, it’s a rich-man’s luxury. It’s for those who have a really efficient solar array with a battery bank, an airtightness barrier that stops the massive majority of warm air loss and cold air infiltration, lovely insulated walls and under the floors, etc. It is simply an add-on that works amazingly under the right conditions, but for most buildings, there are literally 101 things that can, and should be done first before installing one. I think they’re great, but the pure irony of the Government pushing the PAS standards to make sure retrofit is done properly and there’s no more waste as there was in the Green Deal of a decade ago for example, to then go and push heat pumps and ban gas boilers and blame it on energy efficiency and climate change, is certainly not lost on me. This is an attack on the reliance of gas and the power Russia have over Europe, and it’s nothing to do with our industry.


“… improve the thermal efficiency of your building first, before you install a heat pump.”


Yet, here we are, with Governments and “experts” all over the place pushing for them to be installed, despite the massive cost to install them, and the fact that no actually, you are just swapping one form of energy use for warmth, for another. Yes electricity is relatively carbon-minimal, (just made that up,) compared to gas, but you have to use loads of it to run the heat pump, so what are your savings really, in the end?

It’s just all ridiculous, and as with so many things these days, for those of us who aren’t scared little sheep ready to bleat whenever the shephard tells us too, it’s very much yet another case of the Emperor’s Clothes.

Sort your building fabric out first, follow the PAS2030/2035 guidelines as you’re supposed to, and do some more research into the Passivhaus standard and how to do the other 101 things you could do to improve the thermal efficiency of your building first, before you install a heat pump. If you’ve got £12k to spare, you could save far more from the reduction in thermal energy loss of your home, than you would save on your gas bill thanks to a heat pump, and the Government should know this, given that they championed PAS.

I, for one, think they’re all mad.

Rob Green.
Passivhaus Consultant, and straight-talker.
[All opinions are my own, and are not representative of]

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