Matt’s Insulation Transformation
External wall insulation looks neat and can elevate the exterior look of a house. But is it effective? Here’s Matt’s personal experience with the challenges and results of installing EWI in his 1930s home.
The Home:
- House type: Semi-detached 1930s house
- Number of bedrooms: 4 bedrooms
- Location: Bristol
“The Retrofit West home assessment voucher is an amazing service. We’re surprised that we didn’t know about it, and we’ve advertised it to loads of friends.”
Overview
Matt’s seen a 20% reduction in their heating bills since installing external wall insulation. Their home is comfier, retains heat better and looks great.
Summary
External Wall Insulation on side wall
Solar PV
Heat Pump
Background
Matt and his family moved into their semi-detached home with the motivation to re-render the exterior walls for better aesthetics, more comfort and cost savings. Matt is a mechanical engineer and works to decarbonise hospitals around the Bristol area with heat pump projects. They found that when their heating clicked off, it felt cold inside the house – meaning there was significant heat loss through the walls.
In their previous house, they’d insulated the external walls and felt the comfort benefits there and had taken learnings from that process to apply to this house.
Assessment
Matt got 70% off his home assessment for external wall insulation by using a Retrofit West voucher. Finding out they had a whole side wall which was uninsulated meant that it was full steam ahead with the EWI to retain heat and get their energy costs down.
Challenge
With an older building from the 1930s, ventilation is key to keeping the building materials dry and healthy. Matt knew form previous experience that the air bricks in the walls are key to preventing moisture build-up behind the panels and avoiding damp issues. They made a point to inspect the work to ensure the air bricks were used and kept free of debris throughout the process.
Solutions
Over 3 weeks, the external wall insulation was completed by the Home Shield company. By paying special attention to the detailing on the project, Matt had peace of mind that proper sealing, insulative wall-plugs and guttering spaces were used to prevent any future issues. This meticulous approach optimises the final performance of the EWI, meaning it works to insulate the home without any heat loss gaps or moisture damage.
Matt was able to use a Bounce Back Loan which was offered by the UK government post COVID-19. This loan offered a £5,000 grant towards the EWI works. In total, they spent £17,000 on the EWI and felt the benefits instantly.
Results
Before, when their heating clicked off, it felt cold inside the house. After installing the EWI, it’s a much longer period before feeling any heat loss. The house doesn’t ever feel as old and the house is much more comfortable. Heat-loss calculations done in preparation for their heat pump have shown that the EWI has been hugely beneficial and allowed a smaller heat pump to be designed to fit their home and energy use. This has prevented further costs like radiator resizing and larger install works.
Matt’s noticed an estimated 20% reduction in their heating bills as a direct result of external wall insulation. Their gas data has shown a huge 5,938kWh saving over the 3 years post-installation. That’s about £430 in energy cost savings and around 1,114kgCO2!
What’s next for Matt? Once the EWI was installed to better retain internal heat, it made sense to think about upgrading how they heat and power their home more efficiently. Matt’s next step is installing an air-source heat pump and solar PV! Read his heat pump case study here.
Check out Matt’s home in the featured video below!
