The alarming rise in energy prices may have led all of us to question how to consume less power – but this is part of a wider issue too. The government has set a target for decarbonisation to reach net zero by 2050, and household energy consumption is a large part of this. Much of the UK’s housing stock is old, draughty and inefficient and there is much talk of retrofitting properties to bring them up to meet efficiency targets. But what is retrofitting and what does it mean for the average home?
There are around 28 million homes in the UK, and the average Energy Performance Certificate (EPC) rating is D or below. You can make quick, inexpensive improvements by using LED bulbs and smart plugs, or adding draughtproofing to windows and doors, and these will help to reduce your energy use – but the biggest gains come from deep retrofits, or whole house retrofits, which involve making changes to the fabric of your house. Retrofitting typically involves a significant improvement in the thermal performance and comfort of your home by improving the fabric of the building.
Insulation is the main element of any retrofit programme. Installing loft insulation is probably the quickest and most efficient method of improving a building’s thermal performance. Up to 35% of heat is lost through uninsulated walls, and external wall insulation essentially involves thickening the walls from the outside, then sealing the system with a range of render or brick slip finishes. Internal wall insulation involves thickening the wall from the inside. Improving airtightness is key to minimise any gaps in the insulation which could break the continuity and lead to heat loss. Once you’ve improved the fabric of your house, you would then add a low-carbon heating and hot water system, and/or renewables such as solar panels, heat pumps and biomass boilers.
But what about the cost? Fully retrofitting a house can cost anywhere from £40,000 to £200,000, though in the long term you’d hope to recoup the costs in energy savings. Most homeowners are eligible for the government’s Boiler Upgrade Scheme, which provides grants for installing low carbon heating systems, with £5,000 off the cost and installation of an air source heat pump or biomass boiler, or £6,000 off the cost and installation of a ground source heat pump.
The London Energy Transformation Initiative (LETI) is a network of over 1000 built environment professionals working together to put the UK on the path to a zero carbon future. They say: “It is widely accepted that retrofitting our existing buildings is absolutely critical if we are to achieve Net Zero. Around 18% of our annual national CO2e emissions come from existing homes - homes that will still be standing in 2050.” The organisation has produced an informative and easy to understand Retrofit Guide, targeting energy reductions of 60-80% for each home. Here you can look up schemes for different types of properties, and see where the next steps lie. One thing is certain: retrofitting is something we all need to be thinking about, and now’s the time to start.