Happy New Year to all! To my paid subscribers, I am turning payments back on after the December hiatus. Annual subscribers receive an extra month.
The British government is considering a new program of grants to install solar panels, heat pumps and battery storage. Writing on Bluesky, housing policy consultant Anna Clarke noted,
“Sounds like the end of the 'fabric first' mantra being set out here. Electrifying homes is the way of the future, with solar panels, batteries and heat pumps being the focus of government subsidy. 'Fabric first' made sense when we had no alternative to fossil fuel heating, so insulation was to reduce use. And there are still some homes with low-hanging fruit left (loft insulation). But with electricity decarbonising within the next few years, moving off gas has to become the new focus.”
Kate de Selincourt responded:
“Fabric is still first if you want to improve comfort, health and affordability. If you are only concerned about carbon, sure, go ahead and sideline fabric. But you can expect to see fuel poverty, damp and mould increase. (And don't forget that leakier buildings = more generation & more cables)”
But Clarke is correct about changing our focus; since the 1970s, we worried about energy, but now we worry more about carbon, both operating emissions from burning fossil fuels, but also upfront carbon emissions.
And of course, we now have low-temperature air source heat pumps, and the price of photovoltaics has dropped precipitously. As engineer Toby Cambray summarized Richard Erskine in Passive House + in 2022: “A basic fabric retrofit is relatively expensive, and heat pumps are getting better and cheaper; therefore, we should do a bare minimum of fabric work and focus on deploying heat pumps.”
I have been writing about this issue for close to a decade, often drifting from one camp to the other. So please indulge me as I try to work it out here with a bit of history, and try to come to a sensible conclusion.
For many years, I have been a loud proponent of ‘fabric first’ and of deep retrofits to the Passivhaus EnerPhit standard, with its promise of delivering low energy bills, comfort, quiet, and good air quality. However, because of the cost, I also recognized that EnerPhit was probably a thermal bridge too far for the millions of homes that have to be upgraded.
I was also upset about how bad so many retrofits and renovations were, complaining that window and furnace salesmen were driving the bus, often focusing on expensive components rather than making changes that deliver the most bang for the buck. Building on the classic 2006 Minnesota pyramid of energy conservation, I proposed an update in 2021:
Start at the bottom with an audit and a blower door test to figure out where your problems are.
Do the free stuff, like turning things off and lowering the thermostat.
Do the cheap stuff, like caulking and weatherstripping, because we have been grossly underestimating the energy lost through leakage.
Do the big easy hunks, like loft or attic insulation or basement/crawlspace.
Get window inserts as I did; they are a fraction of the cost of new windows.
Get off gas and get a heat pump.
Install photovoltaics if your roof faces the right way.
Do the gut job and go full, properly certified EnerPhit.
Points 1 through 5 are essentially putting ‘fabric first’, but they are relatively cheap, and they make a big difference. I thought it was far more important to do them before you even consider the heat pump and solar; you get comfort, and you reduce demand, and might even get away with a smaller heat pump when you spring for it.
But the phrase “Fabric First” is most often used to describe deep energy retrofits, so Nigel Banks came up with the provocative Fabric Fifth:
Nigel Banks’ Fabric Fifth proposal of 2023 proposes (1) heat pumps, (2) smart controls, (3) measuring, and doing the caulking and easy hunks, (4) solar and batteries, and finally, Fabric Fifth. I have never directly compared my list to his on the same page, but they are not that far apart; if he had put (3) upfront, they would be almost identical. Sorry, Nigel, I shouldn’t have complained so much.
However, I had my feet so deep into the Passivhaus world that I have been loath to give up on full deep retrofits, and continued to push Fabric First, as recently as six weeks ago:
I tried to make the case that heatpumpification may deliver carbon reductions, but not very many people care about that; they want comfort.
“When people spend money on their homes, they don’t want efficiency or a low carbon footprint; they want comfort and health. Yet now we are pushing Net Zero and “fabric fifth” which deliver neither.”
This post got significant pushback from readers, including one named “Lloyd is a hypocrite” and on Linkedin with a long comment from architectural historian Barnabas Calder, that I repeat in full here:
Your definition of success in this field as giving people “what they want” sits slightly at odds with your emphasis on sufficiency. Across most of the affluent in northern climes, we overheat considerably. This worsens condensation and mould, of course, as well as wasting enormous amounts of energy. And the fabric improvements required to bring older UK buildings (pre-1920) up to high winter warmth without excessive energy consumption are extremely expensive and technically challenging.
I write this as someone living in a cold 1910 terrace at 53.4°N. We were making plans to deep retrofit but we just can’t afford it - it would cost more than it cost us to buy the house, plus months of having to live elsewhere with our cats trying to escape and get “home”. I can’t imagine a situation in which enough people will do that to make a significant difference to climate outcomes. We currently live in a messy compromise where we wrap up a LOT warmer than we used to, and keep the heating off or very low, air out the house briefly each day after showers, and sometimes after cooking too, and catch all the sun we can on clear days. It’s not as low energy or as comfortable as deep retrofit, but it’s the least bad compromise for now.
This is why “Lloyd is a hypocrite” is an appropriate label.
I am writing this in a 1918 detached house (at only 43.65°N!) with a gas boiler because until very recently, you couldn’t buy a heat pump in Canada that would work with our cast-iron radiators. I am dressed in the Danish felt slippers I got for Christmas and heavy sweaters because it is -10°C outside, and it is cold and draughty inside. I chose not to do a deep retrofit; I couldn’t afford it and didn’t want to lose all the character of the house which comes from the wood wainscotting and old windows. I am certainly not practicing what I have been preaching.
I also learned from Bill Bordass and Robyn Pender that there are other ways to achieve comfort. They wrote:
“To decarbonise the built environment, it is widely assumed that ‘fabric-first’ building upgrades are essential. An alternative, people-first approach is proposed that could deliver energy and carbon reductions at scale and speed. The approach begins by re-examining some rarely questioned assumptions around historical practices and building science.”
That people-first approach involved clothing and radiant barriers, “most often draperies, canopies, rugs and panelling.” They were not suggesting that we all go medieval, but “The background science and history suggests this could support the sufficiency agenda, improving occupant health whilst using considerably less upfront and operational energy and carbon.”
Barnabas Calder was right to point out that if I am obsessed with sufficiency and the question of “what is enough?”, then I have to ask: is putting on a $20 puffy vest from Uniqlo and a pair of Glerups more sensible than a half-million-dollar retrofit?
How much fabric, where, and when?
So let’s circle back to what started this all in this first post of 2026. Fabric First still matters, but we have to ask, how much fabric, where, and when?
My position is that we should not just throw heat pumps and solar panels at houses without first looking at what we can do at a reasonable cost to reduce demand, or some cold February night, it will come back and bite us when there isn’t enough electricity to meet peak demand.
Kate de Selincourt has done fabulous work on Passive House + documenting how cold, damp and mouldy housing is hurting people in her Cold Truths series. We have to do enough fabric to improve comfort and health. That has to come before the heat pumps.
Even committed Passivhaus people are recognizing that the ground has shifted; Alan Clarke wrote a paper for the Passivhaus Trust, “The right time for heat pumps” looking at staged retrofits, starting with low-cost fabric improvements and heat pumps. The AECB (Association for Environment Conscious Building) has developed a “Carbonlite” certification that starts with a light fabric retrofit, good ventilation and a heat pump.
I wrote a book that starts with the sentence, “When you look at the world through the lens of upfront carbon, everything changes.” And as Barnabas Calder reminded me, I concluded that the solution was sufficiency. I should be asking:
How do we minimize upfront carbon and operating emissions while improving health and comfort with the least stuff for the most people?
The answer may not be “fabric first.” It may be a heat pump and a solar panel. It may be a good pair of long underwear. In 2026, I will not be so doctrinaire.
I understand the issue of people not being able to afford fabric first and it's the reason why governments should offer cheap loads and grants to enable society's housing stock to be improved for the long term benefit of the population and moving to Net Zero. Apart from anything else, adopting the 'fabric first' approach will mean a lower-power heat pump can be fitted and the house will tend to be warmer, more comfortable and less prone to damp and mould issues from cold external walls.
I applaud this subtle shift in focus 👏🏻