Keep An Open Mind
At the time of writing, the methodology for EPC assessments of existing dwellings is RDSAP 10. A significant methodology overhaul from RDSAP to the Home Energy Model (HEM) is proposed for 2027. In addition, government consultations indicate future changes to the format of EPCs and minimum rating levels required for private rental properties. Methods for improving EPC ratings will therefore change in the future.
At A Glance
✓ Not every property can affordably achieve an EPC 'C'
✓ Some building features cannot realistically be upgraded.
✓ Correcting EPC mistakes may still improve the rating.
✓ Documentary evidence can sometimes make a difference.
✓ A Domestic Energy Assessor can model realistic options.
✓ Sometimes you've already achieved the best practical result.
Introduction
One of the biggest obstacles to improving an EPC isn't the property itself—it's assuming you already know what will improve it.
Over the years I've spoken to many homeowners and landlords who were completely convinced they knew which improvements would make the biggest difference.
Sometimes they were right.
But surprisingly often... they weren't.
This happens much more often that you might realise.
Sometimes the answer is surprisingly simple.
Sometimes it's correcting an EPC mistake.
Sometimes it's finding documentary evidence that changes an assumption.
Sometimes it's discovering that the improvement you thought would help... actually won't.
And occasionally, after exploring every realistic option, you may discover you've already achieved the best practical result.
The important thing is to keep an open mind.
Things People Commonly Assume..
"I installed modern efficient electric panel heaters, so my EPC rating should have gone up, not down."
❌ Using single rate electricity to power electric panel heaters results in heating that is expensive to operate. Replacing most other types of heating system with panel heaters will reduce your EPC rating.
Single-rate electricity is an expensive fuel-type and electric panel heaters can only be a maximum of 100% efficient. The marketing hype about them being efficient and controllable is a hoax and simply persuades you that you should reduce consumption by not heating the property.
For an electric-only dwelling the main alternatives are air source heat pumps or high heat retention storage heaters (where appropriate).
For more information on these heating systems take a look at our Heating Systems page and our High Heat Retention Storage Heaters page.
"I've got double glazing, so my EPC should be high."
Windows are important, but heating, insulation and hot water usually have a much bigger influence.
"I know my walls are insulated."
If documentary evidence isn't available, the EPC may have to assume something different.
"Solar panels will always give me an A."
Not necessarily.
"I've installed a new boiler and this should."
Great—but if the loft has only 50 mm of insulation, that could still be holding the rating back.
"I've spent £20,000 in renovating my home, and my EPC rating should have increased more than that."
❌ Improvement measures need to be targeted and modelled beforehand so you confidently know in advance: a) what to implement, and b) the rating outcome. Avoid spending large amounts of money without knowing the outcome in advance.
The cost of works doesn't necessarily go hand in hand with EPC rating improvement. New kitchens, new bathrooms, decorating etc in their own right are simply irrelevant to EPC ratings.
Fitting new double glazing when you already have older double glazing because it's one of the main 5 things that every website tells you to do is also likely to make you very disapointed.
The EPC rating is affected by specific parameters, in specific ranges, and you need to target works that provide the best outcome for your particular property.
There are measures that cost much less and are not programmed to even appear on an EPC as a recommendation.
Consider this example: If you have a hot water cylinder but also have electric showers, there is no programmed recommendation to change those showers to mixer showers. Doing so however could provide an improvement larger than some other more expensive works.
You will not necessarily know what is possible, and may have fixed expectations about what should be required to improve your rating. The best path is to locate a decent energy assessor who will be able to find the best options for you.
"I've already done everything"
Maybe.
But maybe not.
It's easy to get stuck in the mindset of the standard "5 things that improve an EPC rating" that are listed on every other website you've looked at before.
Sometimes the answer is:
- correcting an EPC mistake
- finding documentary evidence
- modelling different options
- or simply looking at the property with fresh eyes.
"My neighbours house is identical so I should have the same EPC rating."
❌ This thought is an easy trap to fall into. No two houses are going to be exactly the same. Much information gathered during assessments is not displayed on EPC certificates.
Small differences can make a surprisingly large difference.
For example:
- heating system
- insulation
- extensions
- glazing
- solar PV
- documentary evidence
- even how the assessment is carried out.
It is possible for two houses that look identical from the road to legitimately receive quite different EPC ratings.
Celebrate What You've Achieved
Even if your EPC hasn't reached the band you wanted, remember that the purpose of improvements isn't just to increase a number on a certificate.
Better insulation, improved heating controls, efficient glazing and renewable technologies often make your home warmer, more comfortable and cheaper to run.
Those benefits remain worthwhile regardless of the final EPC rating.
Click here to return to our 'Improve Your EPC' main page, and see if there is another way you could improve your EPC rating.
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