I’ve been hearing a lot recently about ‘air source heat pumps’ and about how apparently they are the ‘future’ for home heating, being ‘more sustainable’ and ‘green’, compared to mains gas powered central heating systems, which are currently the most popular (and in my opinion best value for money) method of heating homes across the UK.
But after seeing some of the figures being quoted for unit and installation costs, I do wonder whether this is actually worthwhile.
Now of course, our wonderful Government is offering some subsidies to households to contribute towards the cost of installing these units. However I came across this interesting report from the TaxPayers Alliance on the costs of air source heat pumps.
Key findings:
Air source heat pumps are alternatives to gas boilers and are part of HM Government’s net zero strategy. These could cost each household up to £18,000, with costs also including underfloor heating, air distribution systems or improved insulation.
If the grant were offered to the 23 million residential households that do not have an air source heat pump or equivalent, the cost would be £115 billion.
HM Government has announced £4 billion of new funding for decarbonising heat and buildings from 2022 to 2025. 2 This includes the boiler upgrade scheme.The four taxes with explicit environmental objectives raised £2.7 billion in revenue in 2020-21. When combined with other taxes which have a partial environmental objective, the total green tax revenue came to £33.7 billion in 2020-21. This is due to rise to at least £52.6 billion in 2025-26.
Briefing: the cost of air source heat pumps – TaxPayers Alliance
So in a nutshell, these things aren’t cheap. And to be fair, from the images I have seen so far of these units, they’re also pretty ugly.
A heat pump is basically the reverse of an air conditioning unit, or even a fridge freezer. Where air conditioners remove heat from the air, heat pumps aim to do the opposite.
How do these heat pumps work?
Air source heat pumps work much like a fridge operating in reverse. They utilise outside air blown through a network of tubes – via a compressor using refrigerant – to heat air or water which is then circulated around the home.
Heat pumps work best when there is less of a difference between inside and outside temperatures, in much the same way that a fridge has to work harder in hot weather. Air source heat pumps also have a lower output than a gas or oil-fired boiler. This means they can’t deliver heat as quickly. Instead they are best used to heat the home up slowly over a longer period.
And of course, these heat pumps themselves are powered by electricity (they’re not actually magic!).
So what’s the point?
Blah blah, “net zero” or something like that. ‘Net zero’ as in carbon dioxide (CO2) emissions. To save the planet, we all need to stop burning fossil fuels, gas, coal, oil etc.
I understand there is already a long-term strategy in place to phase out gas supplies in the UK, and I forget the year quoted now – probably 2030 or 2040 – but there will be a point where gas-fired combi boilers will no longer be available to buy and install in homes.
These heat pumps are intended to be their replacement, and I believe there is already a desire for all new-build properties to have these installed from the start.
Despite recent price hikes by energy companies, gas is still cheaper than electricity overall. And combi boilers do still require some electricity, in order to power logic circuits, igniters and water pumps.
Well insulated homes don’t need a gas-fired central heating system to be on continuously, just enough to raise room temperatures to ‘comfortable’ levels. 20C is probably about average, certainly for me anyway. I don’t sit around at home during the winter wearing t-shirt and shorts, I’ll have a jumper on.
I have a programmable room thermostat for my central heating system, and it works very nicely for me, only coming on and off when needed, just to keep room temperatures at 20C. Over the course of a day, it is probably using gas for at most 2 hours. It will run for probably about 20 minutes, before shutting off again.
Are heat pumps better then?
Having never used or experienced one myself, I’m not in any position to really offer any expert opinion.
But I do seriously question whether the cost of these units justifies any potential benefits.
Heat pumps work best when there is less of a difference between inside and outside temperatures
So on the surface, they would work best in more temperate climates, where there are less extremes between hot and cold. If its ‘really cold’ outside, like happens sometimes here in the UK, just how effective would these units be?
Air source heat pumps also have a lower output than a gas or oil-fired boiler. This means they can’t deliver heat as quickly. Instead they are best used to heat the home up slowly over a longer period.
So this means that the unit would have to be running for a long period of time – consuming electricity in the process – in order to reach and maintain a comfortable room temperature.
The question that remains to be answered then, is how cost-effective these units would be in regard to the amount of electricity consumed in order to generate or produce the heat required to efficiently warm a home or provide hot water?
What’s the alternative then?
It sounds to me like these heat pumps, as well as being very expensive to buy and have installed, could very well be expensive to have running continually during the winter, especially if the price of electricity continues to increase.
And of course, while a lot of electricity in the UK is generated through ‘renewable sources’ such as wind or solar, there is still a need for ‘coal power’ especially when the sun is obscured by clouds (common in the UK!) or the winds drop.
So much for ‘going green’!
Electric heaters
Going back to my question about ‘cost-effectiveness’, it would seem to me that if gas is to be phased out as a heating source for UK homes, rather than wasting electricity on powering seemingly inefficient heat pumps, why not just use that electricity to power already tried and tested electric heating methods?
I’ve used portable convector heaters, and halogen heaters myself in the past, and I know they can warm up rooms quite quickly. And especially with convector heaters you can get models with built-in thermostatic controls, so they are not on constantly.
Yes, they do consume electricity in order to generate heat, but at least it is ‘direct’ heat, rather than ‘indirect’ heat.
I currently have a 1200W halogen heater at home, and a ‘quick 5 minute blast’ in the evening soon takes the chill from my bedroom.
Storage Heaters
The previous property I lived in had no gas supply, only electric, so made use of storage heaters for heating.
It had an ‘Economy 7’ electricity supply, which was two supply connections, provided at a ‘day rate’ and a ‘night-time rate’.
The ‘night rate’ was provided at a lower tariff, to reflect when electricity consumption was lower. The storage heaters would come on during the night, and basically these consist of a series of ‘bricks’ which would be heated up by electricity, so that the ‘stored’ heat would then radiate during the daytime in order to keep those rooms at a comfortable temperature.
An insulated hot water tank would also be heated up during the night via an immersion heater, so I always had a ready supply of hot water when needed throughout the day time.
Storage heaters aren’t cheap though, costing in the region of £500 each, but I never had to pay this, as they were already installed in the property when I moved in.
The downside with Economy 7 tariffs was that your daytime rates were generally a little higher, but this wasn’t a problem for me as I took advantage of the cheaper night rates by loading and programming things like my washing machine to run overnight when the electricity cost less.
Ironically, I read somewhere before that Economy 7 tariffs were due to be phased out too, probably by 2025 (happy to be corrected), which also seems strange.
My conclusion
I’m not sure if heat pumps are the magic solution to ‘save the planet’ and benefit consumers. It does seem to me though that it has become an avenue for our Government to throw away public money in the name of ‘climate change’, without actually benefitting the public.
Link: Briefing: the cost of air source heat pumps – TaxPayers Alliance
Thank you, excellent description and points.