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If you’ve looked at an Energy Performance Certificate (EPC) recently, you might have noticed something odd. A gas boiler that burns fossil fuels and produces carbon monoxide can be stamped with an A. An electric boiler, almost 100% efficient at the outlet, producing no emissions in your home, often gets marked as a D. Confused? You’re not alone.
EPCs were designed to provide homebuyers and landlords with a quick and easy way to compare properties. One letter, A to G, to show how “efficient” a home is. The idea is simple. The reality is more complicated.
Here’s the catch: EPCs aren’t really measuring what happens in your home. They’re based on models that use fuel price assumptions and grid factors.
Gas is cheaper per unit of energy, so homes with gas boilers tend to score better. Electricity costs more per unit, so homes with electric heating get marked down – even though the system is nearly 100% efficient in the home.
That’s how you can spend thousands on insulation, glazing, solar panels or a new heating system, and still see your EPC score drop.
EPCs are more than just a piece of paper. They:
– Influence the value of your home.
– Decide if a landlord can rent out a property.
– Affect eligibility for green funding or mortgage products.
When the score doesn’t reflect reality, it can mislead both homeowners and installers.
The government’s own consultation admits the obvious: EPCs can’t keep using fuel costs as the headline. Price assumptions don’t align with emissions, and they swing around with the market. That’s why a gas boiler burning fossil fuels can look like an “A” while an electric boiler, 99% efficient at the outlet, gets a “D”.
The fix on the table is a new heating system metric. It would score the technology itself — not just what today’s tariffs happen to say. Gas at the bottom, efficient electric and low-carbon tech at the top.
That matters, because changing a heating system is expensive and disruptive. People need clear, consistent guidance. Not a certificate that shifts when wholesale prices move.
The government has recognised the problem. In a consultation on EPC reform, it admitted that the current approach — a single letter based heavily on fuel prices — doesn’t support the transition to clean heat.
The plan from 2026 is to replace that single score with four headline metrics:
– Fabric performance: how well your home holds heat.
– Heating system: what technology you use, and how efficient/clean it is.
– Smart readiness: how well your home works with batteries, EVs, and flexible tariffs.
– Energy cost: what it’s likely to cost to run.
That’s progress. But until those changes arrive, EPCs will continue to make electric heating look worse than it really is.
For EPCs to be truly useful, they should measure three things side by side:
– Cost (what you’ll pay).
– Carbon (your emissions footprint).
– Consumption (what the home actually uses at the socket).
That way, consumers and installers can make decisions based on facts, not flawed assumptions.
– Homeowners: Don’t panic if your electric boiler or heat pump looks under-rated on your EPC. The system is outdated, not your choice of heating. Look instead at your actual bills, comfort, and emissions.
– Installers: This is a chance to educate customers. Point out that electric systems are efficient in the home, and that EPC reform is coming to reflect that. Customers need reassurance that they haven’t made a “bad” choice just because the paperwork says D.
Gas boilers may carry an “A” sticker today, but that doesn’t make them cleaner or smarter. Electric boilers and heat pumps deliver near 100% efficiency or more in the home and produce no emissions at the point of use.
EPC reform is on the horizon. Until then, remember: the letter on your certificate isn’t the whole story.
Electric Combi Boilers Company
Green Acres
Oakley Green Road
Windsor, SL4 4QF
contact@electriccombiboilers.uk
Call 020 8998 2024
Mon - Fri: 9 am - 5 pm
Sat - Sun: Closed
