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George Clarke looks at the huge challenge to make existing homes zero-carbon

Before I start, a small apology because this blog is insanely long … probably the longest article I’ve ever written in my life … but retrofit is one of the biggest net-zero carbon challenges Britain faces …. and I’m so passionate (and so angry!) about it.

This has taken me ages to research and write, but I just had to do so it this way because it’s such a big, tough issue. So please bear with me. I promise it will be worth it!

In the UK we have a lot of people on a relatively small island and all of those people need to live somewhere.

There are nearly 67 million people living in approximately 25 million dwellings in Britain. In our temperate climate, all of those homes need heating to keep us warm and give us hot water and they also need power to keep the lights on.

That means they need energy and that energy, most of the time, comes from fossil fuels. Although things are beginning to change, our existing UK housing stock has a massive dependancy on, cheap fossil fuels. These fuels are relatively cheap because they are relatively easy to extract from the ground and small amounts of fossil fuels actually generate a lot of energy.

But, those fossil fuels are not going to be cheap forever, and in some cases gas prices remain artificially cheap due to government subsidies.

Now, how can fossil fuels be cheap to extract, transport and sell, yet we live in a country where over 2.5 million currently live in fuel poverty?

And what does the future hold for those in fuel poverty and the rest of Britain when household energy bills are predicted to increase by up to 50% from April?

Lets be honest, fossil fuels are only going to get more expensive as reserves run low.

The short-term and long-term future for fossil-fuel energy looks bleak.

But the way things are now, our 25 million existing homes depend on them.

At this pace, it will take us over 500 years to really become net-zero carbon!

George Clarke George Clarke Architect, writer, TV presenter and Ecodan Ambassador

Look after the old

Britain has an ageing housing stock. In fact, it has the oldest housing stock in Europe.

Now, of course I’m one of the first people to celebrate the period homes and conservation areas we have across the country.  I adore old buildings.

Our history is absolutely fascinating and our past is reflected in our architecture; our houses and buildings tell the story of our nation and millions of tourists come to the UK to admire them. 

But, the sheer number and age of our existing housing stock poses a gigantic problem.

Why? Because the biggest challenge to the UK Government, if it wants to meet its target of being net-zero carbon by 2050, is going to be to retrofit millions and millions of existing homes to massively reduce their CO2 emissions.

If we don’t then the country is screwed. 

It’s worth looking at the sheer scale of the problem.

New build alone is not enough

80% of all the homes that exist today will still be in use in 2050. Of course, some old stock will be demolished to make way for new homes, but 8 out of every 10 of the homes we have now will still exist at the point we expect our country to be net-zero carbon.

Now we should be able to assume that the 20% of new stock we build to replace any demolished old housing stock, will be super-environmentally friendly and zero-carbon.

Unfortunately, it’s not and for many years they won’t be. The new houses we are constructing under the current building regulations are NOT zero-carbon and they aren’t even close.

So, the new build stuff we are building now and for the foreseeable future (unless there is a radical change from government this year!) isn’t going help solve the government’s net zero-carbon problem at all.

As important as newbuild housing is, let’s leave that for another article, because the 244,000 new homes we build each year are only represent 1% of our total housing stock, whereas existing homes account for 99% of our stock.

It is actually relatively easy to design and build brand new ecological products from scratch, because we know how to do it. But, to upgrade, refurbish and retrofit an old ecologically unfriendly house into a super green one is very tough.

It is one if the reasons why many of the big house-builders prefer to build new homes rather than refurbish old ones because refurbishment and restoration is harder. And you pay less tax when you build a new build house (more on this later). The big house builders avoid renovation projects like the plague.

So, for the moment, lets stick with the biggest problem the country faces when it comes to creating a nation of zero-carbon, ecological housing – RETROFITTING OUR EXISTING HOUSING STOCK.

Let’s look at the numbers.

Our existing housing stock accounts for 15% of the UK’s total carbon dioxide emissions. This is mainly generated from domestic boilers burning gas for hot water and heating. That is a lot!

15% percent is around 68 million tonnes of CO2, which is 50% more than the entire agricultural sector produces and it is approximately 7.5 times more than all industrial processes create from steel and cement production to chemical manufacturing.

So, our housing stock is a gas guzzling, carbon emitting, over-heating beast of a problem.

Wasteful and inefficient

Our homes are also frighteningly energy wasteful and inefficient.

The heat we generate escapes from the building fabric of our homes far too easily. That is a huge waste of energy and money.

Only 50% of the homes in England have cavity or solid wall insulation. That’s right, 50% of our entire housing stock has absolutely no wall insulation at all! That’s ecologically insane. 

Only 39% of our homes have 200mm of loft insulation in their roofs! (200mm is regarded as a good amount to minimise too much heat loss through your roof, but this obviously depends on its specification and standard of thermal performance). Less than 200mm is better than nothing, but less effective. 

Surprisingly, 85% of our homes have double-glazing, which is a much higher figure than you might have imagined. However, we have no idea how old and how efficient these double-glazing installations (many of which have been carried out since the 1980’s) really are.

My Mam has double glazing in her house, which was installed years ago by her social housing provider. It is absolutely rubbish.

There is still condensation on the inner pane of glass and the condensation forms mini ponds on the window sills. They let in far too much noise and cold. That shouldn’t be happening at all.

This means that, for whatever reason, the double glazing units and their thermal seals have failed. They aren’t any better than bad single-glazed windows when that happens.

What a complete waste of housing association money and a complete waste of energy (and UPVC!) using a substandard product for a home upgrade.

Not good enough. 

Dependent on gas

So, we use a lot of gas to heat our homes and provide us with hot water, which pumps out dirty air from the boiler’s flue.

A lot of the heat, which the boiler has worked so hard to produce from the expensive gas we have imported from overseas (in 2000 we only imported 2% of our gas, but we now import 60% to replace the reduction in North Sea gas production) is wasted as the heat goes straight out of the window, up through the roof and through the big gaps around our old front door. 

In Britain our fossil fuel dependancy is off-the-scale and we have massively failed to insulate our old housing stock over the last 40 years to prevent the needless and inefficient waste of energy.

Many of our existing homes are expensive to heat and are uncomfortable to live in. 

You might not agree with ‘Insulate UK’s’ methods of protesting, but my god they’ve got one hell of a cause to be campaigning for. 

The government announced that gas boilers will be banned in the construction of all new build homes from 2025. Great stuff and I commend the move, but it’s pretty pathetic in the big scheme of things. This should have been done 10 years ago.

The government made a point in its announcement to keep everyone calm about their precious gas boilers in the existing homes by saying “don’t worry everyone, we are not forcing you to change your existing gas boilers in your existing homes…this is just for new build…so don't worry at all! Keep your gas boilers…”

So, this decision to ban for new houses, sorts out the 244,000 new-build, fully-insulated homes we build each year, but ignores the 25 million old, existing homes that are cold, with little insulation or no insulation.

They’ve solved the easy new-build stuff (well actually they haven’t because all of those new-build homes ARE NOT yet zero carbon!) and they’ve ignored the difficult, but more climate damaging old stuff.

Not good enough.

832 Patrick Mooney GettyImages 1254870580

The retrofit crisis

Millions of existing, inefficient homes will still be here in 2050, when we need to get to net zero

Doing the right thing

Thankfully, some developers and social housing providers aren’t waiting until 2025 and are installing new heat pumps into new houses now, because they know it is the right thing to do. 

Some housing associations are being incredibly brave and are planning major retrofit programmes for their existing house stock, not because the government have told them to do it, but because they have a long-term interest in that stock and they see the long-term benefits to their tenants and to the planet, by doing the right thing. 

Housing Associations and Social Housing Providers want their tenants to be comfortable in their existing homes and they want to reduced their energy bills.

They also know that refurbishing their stock makes it last longer, look and feel better and reduces high maintenance costs that can spiral upwards from neglect.

Retrofitting a tired and cold home can have enormous health, wellbeing and psychological benefits for tenants and homeowners.

That’s how powerful a safe, secure, stable, warm, energy-efficient zero-fuel poverty home can be.

It’s life-changing, life-improving, planet-saving stuff.

It is worth the investment to upgrade and make social housing and housing association stock green as it benefits those most in need.

Many social housing providers have a long-term plan and are pulling out all of the stops to raise the funds to deliver that plan.

Really great stuff and I salute them. 


Unfortunately, it is the greedy, short-term property renovation developers, investors and bad landlords who have no interest in retrofitting existing houses to a high ecological standard, because it has no benefit to them.

It just costs them more money, reduces their profits and they see no point in spending money on energy saving retrofit measures when it’s their buyers or tenants that benefit from the resulting low energy bills.

When it comes to existing homeowners many would love to upgrade their homes to be super green and ecological, but unfortunately so many just can’t afford to do it.

With house prices frighteningly over-inflated and out of sync with annual salaries and soaring living costs, it is hard enough for people to save the money for a deposit and get a mortgage to buy a house, never mind find the money for a significant retrofit upgrade.

The will is there to retrofit, but often the money isn’t.  

 So, for the ‘UK existing home sector’ (that includes every single person, organisation, family trust, overseas investor, housing association, private landlord, refurbishment developer or homeowner that owns any type of existing home in the UK), the government need to step in to provide support, change legislation, increase the standards of the Building Regulations and make everyone upgrade the country’s existing housing stock.

The free market just isn’t going to do it, unless you are a lucky enough to be private homeowner with lots of disposal income to make the upgrades or unless you are a successful and well-managed Housing Association with a viable and deliverable, long-term retrofit plan.

Pull your finger out

The government has set hugely ambitious targets for our country to be net-zero carbon by 2050, but they really need to pull their finger out of their period feature back door and actually come up with a comprehensive and deliverable retrofit strategy to plug the leaking hot-air gap with something more effective than a second-rate draught excluder!  

To be honest, any strategy would be better than what we have now, because the unbelievable truth is THERE IS NO STRATEGY.

I’m serious. 

Even though there has been lots of reports, white papers and millions of recommendations from very, clever people, as I sit here writing this article in January 2022 in the middle of a ‘Climate Emergency’ there is NO VIABLE, SUSTAINABLE, ACHIEVABLE ECONOMIC HOME RETROFIT PLAN FOR THE UK’S EXISTING HOUSING STOCK.

Zilch! Nothing! Nada!

This is incompetence on an intergalactic planetary scale!

George Clarke George Clarke Architect, writer, TV presenter and Ecodan Ambassador

No plan and no radical changes

Of course, we’ve had the usual flurry of positive announcements from Number 10, tonnes of planet-damaging hot-air from ministers claiming that there is a plan to be net zero carbon by 2050.

But when it comes to our existing housing stock there’s nothing. No plan, no legislation and no radical changes in the Building Regulations for the government to meet its own targets.

If it wasn’t so frightening it would be laughable.

I genuinely believe that the UK government is being negligent in its moral obligations to sort out the British Housing system and make it green.

I’m not saying changes aren’t coming. I’m sure they are, but, we have no idea what is coming and when and it takes years for the industry to adapt.

The amount of time it is taking for government to wake up and actually do something radical, which is what the housing market needs, is too slow and simply unacceptable. 

The truth is, since the early 2000’s, every successive government has been hopeless and incompetent with every green initiative it has announced.

Why? Because every announcement made hasn’t been thought through properly.

Sound familiar? Quick announcements to grab positive headlines, but not backed up with any substance or intellectual thought.

I’m sorry but ministers just don't have the knowledge and experience to understand the complexities of housing and the situation is made worse by the fact that the Housing Minister’s job is a very fast revolving door. 

A history of failure

It’s worth mentioning three of the biggest ‘green home’ government schemes that have been announced in the last two decades but haven’t worked. 

We had THE GREEN DEAL in 2013. The government were offering loans for the installation of green technologies and the idea was that through the savings you made on your energy bills, over a certain number of years, you would be able to pay the loan back.

Thousands of Green Deal Assessors parted with their own hard-earned money to get trained up and begin their exciting new careers in the new Green Deal industry – soon to all lose their jobs.

I said at the time that I didn’t think the Green Deal would work, because how many homeowners want to take out an additional loan and more debt against their property so soon after the biggest financial crisis in generations and without any assurances that the savings they may make on the new green technology would be enough to pay back the debt?

They just didn’t trust the scheme…at all!

Also, the green deal wouldn’t work for the ever-growing private rented sector.

Why would a private landlord apply for Green Deal debt just to see those upgrades reduce their tenant’s energy bills?

The scheme was too complicated, too difficult to implement, the public didn’t buy into it and it was frankly a disaster.

The government announced in 2013 to a great fanfare that this revolutionary initiative was going solve the problem of inefficient, energy-guzzling homes and they set a massive target of 14 million existing UK homes being insulated by 2020.

How many homes were insulated under the Green Deal?

Around 15,000.

What a joke!

Zero Standard


This was launched by Gordon Brown and the Labour Party in 2006. It would have ensured that all new-build dwellings be zero carbon by 2016.

How amazing would that have been? All homes Net-Zero Carbon, which is where we long to be.

The industry had 10 years to prepare for it and was ready to go, but David Cameron and George Osbourne scrapped the scheme 9 years later in 2015, literally just a few months before it was going to go live and transform British housing. 

Why did they scrap it? Because they were worried it would reduce the number of new homes being built and they were more scared of missing new home building targets than saving the planet.

So, its fine to build more gas-guzzling, carbon spewing, fuel-poverty inducing homes rather than build fewer clean, green, zero-carbon, zero-fuel poverty homes? Get lost.

Scrapping the Zero Home Standard was the biggest mistake any UK government has ever made when it came to changing the new-build housing industry.

That, for me, was the day the Tory Oak Tree Logo was hacked down and burnt on a massive fire. We have lost 7 years of green home innovation in that time and we’ve built well over a million homes that are not zero-carbon, but should have been!

David Camoron and George Oakburn should be ashamed of themselves!

Build Back Greener

Then there was Boris Johnson’s GREEN HOME GRANT scheme, where money would be given through upfront grants rather than through loans which, as we discovered with The Green Deal, wouldn’t work. 

This was the Prime Minister’s massive post-covid stimulus package of £1.5BN to ‘Build Back Greener’ offering existing households grants of up to £5,000 or £10,000 to install lots of insulation or low-carbon heating to make their dwelling green and cosy. 

Again, the scheme was far too complicated and was completely botched by the government.

Builders complained of excessive red tape and households (for reasons I still don’t understand) couldn’t access the money!

A US company was awarded the contract to administer the grants, but many people didn’t even get any response from them when they applied. 

Boris Johnson, the self-proclaimed ‘Green Prime Minster’, always banging on about how he is going to save the planet and promising that Britain will lead the way in a green revolution cancelled his own flagship, RETROFIT HOMES eco-scheme after just 6 months! YES 6 MONTHS!

He set a headline-grabbing target to transform 600,000 existing homes (remember we have 25 million by the way so it was only going to improve a tiny fraction of our total stock!) with lots of amazing insulation and wonderful air-source heat pumps.

Do you know how many successful applications were actually made? 5,800!

Only 5,800 existing homes benefitted from the scheme and it’s not even clear if all those home improvement works were even carried out, because the scheme was scrapped so nobody that I know of has done any post-assessment work.

It beggars belief. This is government incompetence on an intergalactic planetary scale!

No plans now in place

So, right now, there is no plan in place and somehow we are meant to be net-zero carbon by 2050.

If you don’t mind I’d like to make a few, very simple suggestions to the government about what they could do to make a retrofit start.

These suggestions are very easy to understand, but I’m not saying they would be really easy to implement. However, they wouldn’t be that difficult either if the government got their finger out. The government somehow how manage to find lots of money during a pandemic emergency. I’m sure they can do the same for a climate emergency.

These simple home improvements would make a huge difference to existing UK housing stock and improve the lives of millions of people .

I’ll leave it up to all of those clever people in government and their civil servants and advisers and the Treasury, to work out how they can make this work and help all of us to carry out these works to meet the targets the government has rightly set out: 

Only around 15,000 homes were insulated under the Green Deal. What a joke!

George Clarke George Clarke Architect, writer, TV presenter and Ecodan Ambassador

Practical solutions

  • We need a massive loft, solid wall and cavity wall insulation programme to insulate every single one of our existing homes in the UK to the highest standard possible.
  • We need to fit draught excluders to every single door, keyhole and letterbox in the land and minimise heat loss.
  • We need every new home in the UK to have TRIPLE glazing. Double glazing is so 80’s! When a building regulations application is made to significantly renovate or refurbish an existing dwelling then triple glazing should be compulsory as the replacement.
    Let’s set a date for every single window in Britain to be triple-glazed by.
  • Legislation should make it illegal for old gas or oil-fired boiler to be replaced with a new ones. We need to phase out ALL gas and oil-fired boilers and fast. All boilers should be replacement with clean, green heats pumps and powered by affordable green electricity. 
  • We need to revolutionise the building regulations to turn our fossil-fuel dependant, existing housing stock into the greenest homes they can possible be. It would be the most radical improvements to the building regulations since they were formed.
  • Oh, and we should scrap VAT on the refurbishment of existing buildings! We currently pay ZERO VAT to build a new build home, but we pay a huge and unfair 20% VAT to refurbish an existing home.
    This was brought in by Thatcher to boost the new-build home industry. But, 40 years later it is a stupid tax. THIS HAS TO CHANGE!
  • There should actually be a tax benefit to green retrofit an existing home. You could even argue that taxation should favour retrofit over new build, because there is nothing greener than recycling an existing home as it already contains so much embodied. And if you demolish an existing home you have to get rid of all the waste.

These are just a few suggestions to the government for starters.

To prove I practice what I preach I’ve made ALL of these improvements to my own 53-year old home and the difference is unbelievable.

That’s why I recommend them because I know they work. My old, cold house is now off-the-scale comfortable and ecological with amazing thermal and acoustic insulation. It was also a very satisfying day when my gas-guzzling boiler got ripped out and replaced with a heat pump!

It’s just a shame the UK Government taxed me 20% when i made these much needed ecological improvements because, let’s face it, that money was either squandered on another report or white paper the government can ignore or maybe it was wasted on Boris Johnson’s annual hair salon bill. Who knows?

What about the cost?

So, how much do we think it’s going to cost to fully retrofit all the existing house in Britain?

Well, we don’t really know because so many houses are different, different styles and sizes, built to different standards, some have been maintained well when others haven’t, some have already had some ecological improvements, where other have had none.

Also, material prices and labour costs vary for retrofit work depending on where you are in the country so we actually don’t know the true cost of retrofitting every home is Britain.

But, there is an average figure.

I’ve no ideas how this figure has been worked out and I always worry about ‘average’ figures because they can be misleading. However, The Climate Change Committee (who advise the Government) have estimated that it will cost an average of around £26,000 to ecologically retrofit each home in Britain.

Of course, for many, this is not a small amount of money. But, we know we need to do this, so somehow we need to make it happen.

Doing nothing is not an option.

It’s worth mentioning that in some parts of the country house prices are actually going up by way more than £26,000 every year. So, you could argue retrofitting these homes in high-price-rise areas makes green home improvements very affordable.

Unfortunately, in other parts of Britain, there are only small increases in annual house prices. It is in these areas of low property values and low incomes where there are the highest levels of household fuel-poverty and with very poor levels of home comfort.

These are areas and the homes with the greatest need for an ecological upgrade.

Nobody should have to decide whether to eat or heat their home, but there are hundreds of thousands of households per day across the UK that have to make that awful choice. Heat your home or feed you kids.

We are supposed to be a developed country for God’s sake!  

We need a retrofit strategy

So, we somehow need to create a very clever financial model and have retrofit strategy that balances out, levels-up and helps those most in need of having their homes upgraded, while dramatically improving their levels of home comfort and dramatically reducing their home energy bills.

At the same time, making major changes to the Building Regulations and bring in tough, new, super-green legislation to make those who can definitely afford it, get on and refurbish their existing homes to the highest possible ecological standard.

I genuinely worry every day that the current rate of progress and change by the government is shockingly slow and incompetent, and with so many failed government green schemes behind us, we have lost valuable time.

Predictions are that if we continue along this ridiculously slow, feeble and ineffective path to becoming a green nation, it will take us over 500 years to genuinely become net-zero carbon!

Yes folks …. over 500 years!

We don’t have that time. We need to stop the massive, inefficient and uncomfortable waste in heat energy 

If the government don’t change their course and do something radical and fast, particularly with our ageing existing housing stock, there is absolutely no chance we are going to be a net zero-carbon country in 2050.

Unfortunately, I actually don’t think we are going to make it. I really don’t.

But, that doesn’t mean we shouldn’t make a start. 

Massive inequality

Many will say we can’t afford it, but I actually don’t buy that at all.

One of the biggest problems is that in the UK and across the globe we have massive inequality between the rich and the poor.

The poor are those most in need and it is obvious that the poor won’t be able to afford to ecologically upgrade their homes.

But the brutal truth is that our over-developed planet is absolutely loaded with money. We have never been so rich as a planet. There a billions and billions of pounds sloshing around and a lot of that money, you could argue, has actually been made at the expense of the planet.

It’s time to pay the planet back.

And if this really is a Climate Emergency (it REALLY is!) then the money needs to be made available now so fix it.

Earth PLC has the money. We just need to decide to spend it on Climate Change rather than things like bombs, which we aren’t going to need when we screw the planet by over-heating it. 

Those that can afford to upgrade their homes should be made to do it.

Those who cannot afford to upgrade their homes should be supported in every way possible to help them do it.

Rebalance the money and Retrofit. 

If the Earth really is our collective home, then we need to do things very differently and very quickly to save it. 

We cannot afford to not RETROFIT BRITAIN.  

George Clarke is an Architect, writer, TV presenter and Ecodan Ambassador