Checking your home's Energy Performance Certificate (EPC) can reveal why it turns into an oven during a heatwave and how to cool it down effectively. For one family, rediscovering their EPC during a rare red heat alert, when temperatures approached 40°C, provided crucial insights after years of struggling with trapped heat in their 1920s bungalow.
What is an EPC and Why It Matters
An EPC rates a property's energy efficiency from A (most efficient) to G (least efficient), based on insulation, windows, heating systems, and lighting. It is a legal requirement when a property is built, sold, or rented in England, Wales, and Northern Ireland, valid for 10 years. Yet many homeowners ignore it after moving in.
The certificate also estimates energy costs and carbon emissions, plus lists recommended improvements with estimated savings. For the family, their bungalow had a D rating, typical for older homes, but the detailed breakdown was more revealing.
The Insulation Trap
Under the EPC, individual elements like walls, windows, and roof are scored from 'Very Poor' to 'Very Good'. The family's roof insulation was rated 'Very Good', but in summer, that became a problem. British homes are designed to trap heat in winter, so hot air rising upstairs gets trapped by high-performing insulation, with no escape route.
"I’ve always thought of insulation as a winter asset to lower heating bills. But insulation works both ways, just like a thermos flask - keeping things hot just as effectively as it keeps them cold," the homeowner noted. Older UK homes were not built for extreme summer heat, unlike homes in hotter climates like Delhi, which are designed to release heat.
How to Check Your EPC for Free
You do not need to pay a surveyor or dig through old paperwork. The UK Government maintains a free, public online register. Simply visit the official portal, select domestic or business property, enter your postcode, and click on your address to unlock your home's full history, including past certificates. For Scotland, use the separate Scottish EPC Register.
The EPC provides a full breakdown of how different parts of your home perform, along with suggested improvements tailored to your property, such as better glazing, ventilation tweaks, or insulation upgrades, with estimated costs and savings.
Immediate Cooling Fixes
Based on the EPC insights, the homeowner focused on strategic fixes: installing reflective window film to bounce sunlight away, putting up heavy thermal blinds on the sun-facing side, and carefully timing window openings to prevent outdoor heat from entering. These actions work with the house rather than fighting it blindly.
"I ignored our EPC for two years, but it turns out to be the most useful piece of paperwork in the house. It didn’t magically cool my house down overnight. But it did explain why it feels like this - and gave me a clearer idea of what to fix long-term," the homeowner added.
Energy Bills and Future Relief
With energy bills set to jump 13% from July, understanding your home's efficiency is more important than ever. The Warm Homes Plan and other schemes aim to help, but many households are not reaching those who need it most. Checking your EPC is a free first step to identifying improvements that can lower bills and keep your home comfortable year-round.
