Insulate Britain Or Miss Net Zero Target
30th June 2022
The UK is failing to enact the policies which would put it on track to reach net zero emissions by 2050, according to a progress report by the Climate Change Committee. The head of this expert body, which advises the government on its climate strategy, described the UK's record on home insulation in particular as "a complete tale of woe".
Gas heating in draughty homes is one of the country's biggest sources of carbon emissions - and a leading cause of poor health and poverty as energy prices remain sky-high. So what would it take to turn this around?
You're reading the Imagine newsletter - a weekly synthesis of academic insight on solutions to climate change, brought to you by The Conversation. I'm Jack Marley, energy and environment editor. This week we're offering the government an expert-approved plan for insulating Britain against soaring energy bills and the climate crisis.
"The transition to net zero emissions is often framed as a race to make new stuff - such as electric vehicles and wind turbines - as fast as possible," says Ran Boydell, a visiting lecturer in sustainable development at Heriot-Watt University.
"That's actually the easy part. The hard part will be modifying what already exists - and that includes people's homes."
Cavity wall insulation, triple-glazed windows, solar panels, low-carbon heating systems such as heat pumps which run on electricity: all of these things and potentially more are needed to neutralise the contributions to climate change made by 26 million homes (the number of existing homes Boydell anticipates will still be around in 2050). That would eliminate 68 million tonnes of CO₂, which is about 15% of the national total.
"The idea is to ensure that no home emits greenhouse gases by burning fossil fuels for energy and that, eventually, each home could produce as much energy as it uses," Boydell says.
According to analysis by the Climate Change Committee, the average cost of retrofitting a single home to net zero standard is £26,000. Energy savings would make up for this after 20 years, but most households would struggle to make such a big upfront investment.
"Considering energy efficiency measures purely in terms of financial payback will never stack up," Boydell says. "They must be considered in terms of carbon payback. Carbon payback is how quickly the reduced carbon emissions from daily life in a net zero home take to make up for the carbon emissions that went into making and building all the different parts."
A home operating at net zero standard would compensate for the carbon that went into building it after just six years, Boydell estimates. But it's the responsibility of the government - and not individual homeowners - to juggle these considerations, he says.
"Infrastructure, like roads and railways, is the only stuff people build which counts its payback periods in decades. The government needs to think of a mass retrofit programme for our houses in those terms: as critical national infrastructure."
Matthew Hannon and Donal Brown study green policy at the universities of Strathclyde and Sussex. They say that:
"At an absolute minimum, the government should be aiming to install insulation in 1.3 million homes a year - a rate it managed pre-2013."
To reach that level, Hannon and Brown have four suggestions. First, increase annual funding for retrofitting homes from £1 billion to £7 billion - enough to retrofit 7 million homes by 2025, they claim. Next, shift the burden of raising this money into general taxation and away from energy bill levies which strain the poorest households and inflate the cost of heating homes with zero-carbon electricity.
"Insulating hundreds of homes at a time, neighbourhood by neighbourhood and coordinated by local authorities, could help to retrofit housing deeper and faster than tackling homes one by one," they say. For this, collaboration with local groups and businesses who know the community well will be key. Hannon and Brown argue the government will also need a separate, well-funded programme to install heat pumps and other low-carbon heating systems, while phasing out support for gas boilers.
Once a national campaign to renovate Britain's homes to net zero standard is underway, there are certain to be teething problems. The Labour Party offered a comprehensive programme of home insulation at the 2019 election. At the time, Jo Richardson, a professor of housing and social inclusion at De Montfort University, and David Coley, a professor of low-carbon design at the University of Bath, described the obstacles that will need to be overcome.
"The UK construction sector is highly fragmented – and different subcontractors are often responsible for the walls, roof and electricity in a single house. This makes quality control difficult. There's also a skills shortage, especially when it comes to the detailed knowledge required to build a zero-energy house. And if energy-consuming extras such as underfloor heating or electrically driven windows are added, the energy savings from design may be lost," they say.
The Climate Change Committee noted that new homes are rarely net zero standard, with 1.5 million built in recent years that will need to be retrofitted. The preferred solution for Richardson and Coley is to mandate each new home to Passivhaus standard, which certifies that it produces as much energy as it uses.
"Passivhaus only works if the right design decisions are made from day one," they caution. "If an architect starts by drawing a large window for example, then the energy loss from it might well be so great that any amount of insulation elsewhere can't offset it. Architects don't often welcome this intrusion of physics into the world of art."
Increased funding, new regulations and an overhaul of architectural norms will be necessary to roll out zero-energy homes and retrofit existing ones. "That's a tall order," say Richardson and Coley. "But decarbonising each component of society will take nothing short of a revolution."
Note
the above article is from the conversation web site published 29 June 2022.
Five numbers that lay bare the mammoth effort needed to insulate Britain's homes
Published 14 September 2021
Environmental activists recently blocked junctions of the M25 – London's orbital motorway – to protest the glacial pace at which the UK government is tackling carbon emissions and fuel poverty in Britain's housing stock.
Arguing that the country has "some of the oldest and most energy-inefficient" homes in Europe, the group known as Insulate Britain has vowed to continue campaigning until the government "makes a meaningful commitment to insulate Britain's 29 million leaky homes".
The transition to net zero emissions is often framed as a race to make new stuff – such as electric vehicles and wind turbines – as fast as possible. That’s actually the easy part. The hard part will be modifying what already exists – and that includes people’s homes.
Neutralising each home’s contribution to climate change will require a range of installations, including wall insulation, double- or triple-glazed windows, a heat pump or another low-carbon form of heating, and solar panels. Making these changes is known as retrofitting. The idea is to ensure that no home emits greenhouse gases by burning fossil fuels for energy and that, eventually, each home could produce as much energy as it uses.
Sound simple enough? Here are the five numbers that explain just how big a task it really is.
1. 68 million tonnes
About 15% of the UK’s total carbon emissions – 68 million tonnes – comes directly from homes, mostly from boilers burning gas for hot water and space heating. That’s more than the entire agricultural sector at 10%, and many times the 2% from industrial processes, such as cement, steel and chemical manufacturing in 2019.
2. 26 million
Some of the UK’s existing 29 million homes will be demolished by 205O, but it’s estimated that around 26 million will still be around. These will all have to be retrofitted to net zero standard.
To put that another way, about 80% of all the houses that will exist in 2050 are the houses that people are currently living in. Only 20% of the houses will have been built from scratch to net zero standard.
3. £26,000
The cost to retrofit a typical family home to net zero standard is estimated at about £26,000. This is based on an analysis of work by the Climate Change Committee – a body of experts that advises the UK government.
Multiply those 26 million homes by £26,000 and the overall price tag is £676 billion. Averaged over the next 25 years, retrofitting Britain’s homes could amount to £27 billion a year. That is about the same as the entire annual spend on home repairs and maintenance, and more than half as big as the market for new-build homes.
A mass retrofit campaign wouldn’t just be a step-change in the construction industry, it would be an entire additional sector. But it would also be time-limited. Once all existing homes are retrofitted, it will come to an end.
4. 20 years
How quickly savings from an investment repay the initial expense is known as the payback period. In theory, a net zero house could have zero energy bills, as it would save and generate as much energy as it uses. The average annual energy bill is £1,289, so the payback period for a £26,000 retrofit would be just over 20 years.
But the payback period for each individual retrofitting measure tends to be longer. Improving window glazing tends to pay for itself after about 40 years. Roof and wall insulation is even longer at 46 years. Solid wall insulation, which will address the single biggest source of heat loss for older houses, has a payback period of 16 years.
Calculating the payback period for a heat pump is more complicated, as it typically replaces gas in a boiler with electricity. These energy sources have very different cost structures. Currently, the UK has one of the cheapest gas prices in Europe, but one of the most expensive electricity prices.
When considering the financial payback on an investment in energy efficiency, most households will struggle to look beyond five years, perhaps 15 years at most. But considering energy efficiency measures purely in terms of financial payback will never stack up. They must be considered in terms of carbon payback. Carbon payback is how quickly the reduced carbon emissions from daily life in a net zero home take to make up for the carbon emissions that went into making and building all the different parts.
For a home retrofitted to net zero standard, the carbon payback might be about six years. For individual parts it can be even shorter: solar panels have a carbon payback period of just 1.6 years.
Infrastructure, like roads and railways, is the only stuff people build which counts its payback periods in decades. The government needs to think of a mass retrofit programme for our houses in those terms: as critical national infrastructure.
5. 20%
The VAT rate applied to any work on existing homes – whether it’s maintenance, extensions, or retrofitting – is 20%. While there are some exceptions where the rate is reduced to 5%, these are only available to a small range of homeowners, such as those over 60, and only where the works are exclusively for the sake of energy efficiency, rather than as part of a broader home-improvement project. So the use of this rebate is minimal.
For private homeowners who are required to pay for retrofit measures like wall insulation or heat pumps from their own pocket, the so-called "able to pay" market, that 20% VAT might represent more than £4,000 of the estimated £26,000 cost.
By comparison, building a new home is zero-rated for VAT. This creates a financial incentive to demolish and rebuild rather than retrofit.
There have been many attempts to make the government change the VAT rules on this, including a recent one supported by the banking sector, but so far without success.
Decarbonising Britain’s housing stock is a huge challenge, but also a huge opportunity. Kickstarting the home insulation and retrofitting programme will only happen with government support, it is simply not something that normal market mechanisms can drive. Let’s hope public pressure can convince the government to change course fast.
