As energy costs continue to squeeze household budgets, a quiet revolution is transforming older UK homes into warmer, cheaper, and more valuable sanctuaries. The key lies in 'retrofitting' – a series of eco-friendly upgrades that seal in heat and slash running costs, yet many homeowners remain unaware due to a surprising knowledge gap in the building trade.
The Builder's Blind Spot: Unlocking the Retrofit Potential
Judith Leary-Joyce, an advocate for eco-renovation and author of the new book What The Builder Won’t Tell You, warns that builders often fail to prioritise energy efficiency. "Builders don't yet have this on their radar," she states. "The most they’re likely to do is suggest standard levels of insulation and a more efficient gas boiler."
Leary-Joyce, who also penned the Beginner’s Guide To Eco Renovation, transformed her own Victorian terrace with a full retrofit. The results were staggering: a 75% reduction in energy usage, a much warmer home, and a valuation £90,000 higher than comparable, unimproved properties on her street.
She defines retrofit as a holistic approach encompassing superior insulation, enhanced airtightness, intelligent ventilation, and sustainable heating systems like air or ground source heat pumps. The goal is a comfortable, mould-free home that's cheap to run and future-proofed.
Four Eco-Upgrades Your Builder Might Not Suggest
1. Look Beyond Synthetic Insulation
While insulation is crucial, Leary-Joyce stresses that the material matters immensely. She warns that many builders default to cheap, plastic-based synthetic insulation, which acts "like wrapping your home in a big plastic bag." This can trap moisture, leading to condensation and making homes unbearably hot in summer.
The solution lies in natural, vapour-permeable materials like wood fibre or sheep's wool, especially for older properties built before 1930. "These manage moisture well and keep you warm and cool," she explains, but most builders are unfamiliar with them.
2. Master Airtightness to Seal in Savings
Investing in fancy heating is pointless if warmth escapes through countless tiny gaps. "If you insulate without airtightness, you’ll be disappointed," Leary-Joyce cautions. Achieving this requires meticulous sealing of every joint, pipe inlet, and even ceiling light fittings.
She admits, "I haven’t yet met a standard builder who knows anything about this," advising homeowners to be vigilant and insist on proper attention to detail during renovations.
3. Upgrade Ventilation Beyond Trickle Vents
A family of four produces around 20 litres of moisture daily. In an airtight home, this dampness lingers, creating a perfect breeding ground for mould. While builders might only mention basic window trickle vents, Leary-Joyce advocates for proper mechanical ventilation systems.
These systems filter allergens, remove moisture, and can even aid in drying laundry. "Trickle vents are definitely not enough if any attempt to retrofit has been made," she stresses, suggesting builders should revisit properties a year later to see the consequences of poor ventilation.
4. Understand the Heat Pump Advantage
Describing heat pumps as a 'Marmite issue', Leary-Joyce acknowledges divided opinions but underscores their efficiency when correctly installed. They provide steady warmth by extracting heat from the air or ground, even in cold weather.
The critical metric is the Coefficient of Performance (CoP). She illustrates: putting £1 into a gas boiler yields about 70p of energy, while £1 into an air source heat pump can return £3 to £4 worth. This stark efficiency gain is rarely explained by builders.
Driving Change: The Homeowner's Role
Leary-Joyce believes the lack of information is rarely malicious but stems from a lack of builder awareness. "I think the majority just don’t know about the different options," she says. However, when builders are guided to use natural materials and modern methods, they often appreciate the safer, less toxic work environment.
The power, therefore, lies with informed homeowners. "You need to know what the builder can’t or won’t think to tell you," she asserts. By understanding the basics of retrofit and clearly specifying their desires, homeowners can drive industry change, creating more comfortable, valuable homes ready for a sustainable future.
What The Builder Won’t Tell You by Judith Leary-Joyce is published by AoEC Press, priced £12.99, and is available now.
