Our home renovation is complete. I want to show my friends. But it turns out they are interested in one thing: the heat pump.
For the past year, our London home has been a completely fossil-fuel free zone, heated by a chunky Samsung 12KW air-source heat pump. And since it was installed, I have been taking bookings from friends, colleagues, neighbours and strangers to come and see it.
“Ta-dah,” I say. Maybe this is what housewives felt like in the 1950s, unveiling their state of the art dishwashers.
Let’s be clear, I’m no early adopter: heat pumps have been around for decades. In 1948 the British journalist Gordon Cook observed “there can be no doubt that in the heat pump we have a machine that is to play an outstanding part in the industrial future of our country”. But they didn’t catch on — and installing them is not a well-trodden track.
The UK has lagged behind other European countries in adopting gas-free heating. With many on the continent taking up subsidy schemes, there has been a 65 per cent increase in the number of pumps in the past four years. Norway is winning the race: about two-thirds of households have a heat pump. Yet in the UK, only 250,000 of us have transitioned so far and heating still accounts for about 14 per cent of the country’s greenhouse gas emissions.
London is not keeping up with the rest of the UK in signing up for Boiler Upgrade Scheme funding — with only 1.6 households per every 10,000 in the capital receiving money (compared with 10 per 10,000 in the South West). If the country is to meet its climate targets, about one in 10 homes will need to phase out their gas boiler by 2030. Right now, most people would struggle to pick a heat pump out of a white goods line-up. We are not on track to meet government targets. More of us need to get pumping, and fast. Our neighbours have come to peer into their future.
Our heat pump was part of a broader eco-retrofit. Our kids were turning into teenagers and our house needed to evolve. We looked into moving but it became more attractive to stick and adapt. And we wanted to do it as sustainably as possible. But I have to be honest and say that the green motives weren’t always top of our agenda. One driving reason for the renovation was wanting a bigger, more exciting, light, usable living and entertaining space.
We decided to lose the floor between the lower back room and upper ground reception room to create a double-height kitchen. High ceilings are not ideal for efficient heating, the heat rising uselessly to the top of the room, and that came with challenges.
The build process turned out to be more adventurous — and, inevitably, more infuriating — than we imagined. They said six months; we spent 12 months with the contents of our house in three storage units. We travelled the classic Grand Designs narrative arc: over-ambition, clearly foreseeable setbacks, marital strife and financial strain. (The heat pump, to be clear, was only a minor part in this.)
The government gives a five bullet-point summary (issued under Boris Johnson) of why we should convert to a heat pump, but really it’s a clear two: it’s cheaper in the long run and far cleaner.
The prospect of completely electrifying was nerdily exciting. Our house is a “typical” Victorian terrace in Hackney, built when the London sky was thick with smog. We have now got rid of the Victorian chimney flue, the gas boiler, gas oven and hob. The heat pump extracts ambient heat from the outside air to heat the house, and solar panels take energy from a star 93mn miles away.
Despite the history of heat pumps, it all felt a bit like we were investing in a novel technology. My parents had bought the Betamax video player before the VHS took over and refused to switch, so my sister and I spent our 1980s childhood watching recordings of Tootsie and Kramer vs Kramer on repeat. Was I repeating the errors of my parents?
There are plenty of naysayers and negative tales around heat pumps. Many on the political right argue that they are costly, noisy, don’t effectively heat houses (especially old ones) and require too much space and too many associated home upgrades (such as extra insulation) as part of the installation. The green energy industrialist Dale Vince has described the heat pumps drive as “Ulez on steroids”, and says that “the heat pump programme is illogical, impractical and uneconomic”.
I’m a fan of breathing cleaner air outdoors thanks to Ulez — and indoors thanks to heat pumps (gas boilers emit nitrogen oxides). Strengthening my resolve was the International Energy Agency assertion that heat pumps are three to five times more efficient than gas boilers.
The heat pump we chose was the second biggest on the market, and so at the higher end of pricing options. It cost around £17,000, but the Boiler Upgrade Scheme grant knocked off £7,500. We were advised this was appropriate for a four-bedroom house that would be relatively but not perfectly insulated. Being on a terrace, two external walls instead of four meant we didn’t have to go for the most expensive option. But, because our house isn’t a new-build, we couldn’t reach the highest insulation spec. This subsidy (boosted a year ago) is an incentive to jump on the pump wagon before the tap runs dry.
The pump operates at a lower temperature than a cranked-up radiator, which means it’s best to spread the heat output over a larger surface area. As part of the broader remodelling, we removed all the radiators and installed underfloor heating on the lower and upper ground floors (which I have always coveted anyway).
To mitigate the double-height kitchen ceiling, the heat pump installers also recommended that we put water pipes in the wall, basically underfloor heating up the wall (behind a thin plaster cover). It works. Now the room has a more even heat at different levels. It is quite weird to feel warmth from the wall, a giant radiator. We haven’t dared to try hanging a picture, though; water wall fountains would be a less welcome architectural feature.
There is also a fear that invasive insulation is required to make heat pumps work most efficiently, especially if you live in a property that’s more than 100 years old. But recent studies show that worry is overblown: 85 per cent of homes in the UK don’t require extra insulation to make it work, according to the research and technology organisation Energy Systems Catapult. Heat pumps are installed in churches, stately homes and all sorts of old buildings. “Most people are likely to be surprised their home is heat-pump ready without expensive or disruptive insulation,” says environmental engineer Ben Allwood, who works with architects on retrofits, including our architect Kenny Forrester.
It’s hard to quantify the insulation we installed exactly for this purpose because it was combined with having to dig down into our lower ground to lay the floor insulation, and we ended up replacing the entire roof of the house, though this was combined with adding a large dormer window.
We don’t live in a conservation area, and our house isn’t listed, so we were able to put the heat pump in the front garden under permitted development rights. But at the time of writing, there are still restrictions on where you are allowed to place your heat pump; such as the need for it to be more than 1 metre away from the property boundary.
Leyla Boulton, co-founder of Green Conservation group and an FT colleague, has set up a campaign to make retrofitting easier. “The key is to have an expert heating engineer installer. An architect recommended [I install] a bigger heat pump that required planning permission in a conservation area, whereas specialists Heat Geek said a smaller 7KW one would do nicely with some new radiators.”
Our heat pump complied with this 1 metre rule but is just about visible from the street and does hum a little; the purr of environmental virtue signalling. The official sound limit for a heat pump is set at 42 decibels. But when I cautiously asked my neighbours, they said they couldn’t hear it.
One huge hurdle for us was the lack of experience in installing heat pumps. The chain of communication between the architect, the building contractor, the energy contractor and then the subcontractor felt fraught — pushing it all through felt a bit blind leading the blind. There are companies trying to make the process and knowledge gaps easier to navigate. I see now why they are needed. Heat Geek helps find the right installers, as does MCScertified.com.
I also do wish someone had told me that the fan violently chucks out cold air. If the pump were to go in your back garden you wouldn’t want it next to your picnic table. Our pump is directed at the front of our house, cooling in the summer perhaps but not ideal in the winter. Though I have since discovered I can get a rather tasteful cover to direct the air away (heatpumpenclosures.co.uk).
Finding a spot for the external heat pump is one thing, but a space is also needed for the internal plumbing and the hot water tank. We had to create a boudoir for all the gurgling pipes and switches, basically a large cupboard — remember airing cupboards from before the massive mistake of combi-boilers 20 years ago? Well we are basically back there.
Tougher green energy regulations are slowly being introduced. But Andrew Sissons, deputy director at innovation foundation Nesta, says: “Many new homes are still being built with gas boilers, and it won’t be until the government’s long-delayed Future Homes Standard fully kicks in over the next few years that this stops.”
Rising energy costs are, however, helping to change mindsets. Jignesh Patel, managing director of heat pump installation company Ramki, says: “We have seen a real shift in people being more energy conscious since the rise in energy prices two years ago.” Heat pump installations in the UK were up 20 per cent in 2023, according to the Microgeneration Certification Scheme (MCS).
I think the main lesson I have learnt from this renovation is what I’ve learnt about parenting — good enough is good enough. We don’t have to be Passivhaus evangelists. But we can — and should — do something.
Still, I couldn’t help but raise a “Yeehaw” when Nesta’s Sissons told me that my heat pump has reduced our annual carbon footprint by the equivalent of around eight flights from London to New York. (You can do your own calculations on the site.)
We have also changed from our gas supplier to Octopus Energy, one of several electricity companies that offers tariffs tailored to heat pumps. We are on its “agile” tariff, where lower electricity prices are at certain times in the day. Likewise, we installed the HavenWise app, which remotely regulates the heat pump to further minimise the costs. As we get to grips with how to operate it, I hope to reduce our bills. But for me, the other benefits were enough to embark on the admittedly complex journey.
Many of the lifestyle changes we are encouraged to make, like eating less meat and flying less, can feel like a sacrifice. But a carbon-free home feels cosy: out with the smog and in with the smug.
Having come round to peer at the heat pump, my friends and neighbours are, I hope, now inspired to get one — not least so I can stop doing tours of mine. Apparently, we can sign up for a scheme, creatively named “Visit a heat pump”, where we can open our home for people to check it out. I’m up for being an ambassador (if you can, you should) but hopefully this article is enough. There’s only so many times I want to talk pump.
Juliet Riddell is the FT’s head of new formats
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