How to Improve Your EPC Rating, From Cheap Fixes to Big Upgrades
Updated: Oct 9
The upgrades that improve an EPC rating most are the ones that cut heat loss and make heating cheaper to run: wall insulation, loft insulation, better heating controls and a more efficient heating system. Quick jobs such as a hot water cylinder jacket and LED bulbs help a little, but rarely lift a home by a whole band on their own. Start with the recommendations on your current EPC, do the cheap ones, then plan the bigger ones in the order that suits your home.
How is an EPC rating worked out?
An EPC rates a home from A (most efficient) to G (least). The Energy Saving Trust explains that although it looks like an efficiency score, the band is based on the modelled cost of heating, hot water and lighting per square metre, using standard fuel prices rather than what you actually pay.
That tells you where the points are. Anything that reduces heat loss or makes heating cheaper to run tends to move the rating most, which is why insulation and heating upgrades sit at the high-impact end of the Energy Saving Trust's list, while it says LED lighting is not likely to make a huge difference.
It also explains a common surprise: homes with electric heating can score lower than similar gas-heated homes, because electricity has a higher standard unit price in the model.
When we carry out EPC certification, the assessment records the walls, roof, floors, windows, heating, hot water and lighting, and the certificate then lists recommended improvements with the rating the home could reach. That list is the best starting point for any plan.
Cheap improvements to do first
These cost little and are quick. They will not change a rating dramatically, but they tidy up easy points before you spend serious money. The costs and savings quoted in this post are the Energy Saving Trust's typical Great Britain figures (guide last updated August 2026), not quotes.
Insulate the hot water cylinder. The Energy Saving Trust puts a cylinder jacket at about £30. If the tank has factory foam, check it is at least 80 mm thick; a thin coat is worth jacketing.
Switch to LED lighting. Replacing halogen bulbs with LEDs saves around £45 a year in Great Britain, but the Energy Saving Trust says it is not likely to make a huge difference to the rating.
Draught-proof gaps. Sealing gaps between floorboards and skirting is a DIY job, as long as the room keeps enough ventilation.
Does LED lighting improve an EPC?
A little. Lighting is part of the calculation, so a home lit entirely by old halogen or incandescent bulbs will score slightly better once it is all LED. The Energy Saving Trust says the switch is not likely to make a huge difference to the rating, so do not expect it to close the gap to the next band.
Where LEDs do matter is in homes with lots of fixed halogen downlights. Swapping these is sometimes more than a bulb change: low-voltage (12 V) halogen downlights run from transformers that may not work reliably with LED lamps, so the fitting or driver can need changing too. That is electrical work we do day to day, and it is worth doing properly rather than mixing lamps and fittings that do not match.
Mid-cost upgrades: heating controls and loft insulation
Heating controls. A full set means a programmer, a room thermostat and thermostatic radiator valves on the radiators. The Energy Saving Trust puts a full installation at around £600 and a saving of about £100 a year for an average semi-detached house. This is heating engineer work, not electrical.
Loft insulation. About a quarter of the heat from an uninsulated home escapes through the roof. Topping up from 120 mm to at least 270 mm is one of the cheaper insulation jobs and can be DIY if the loft is dry and easy to reach; otherwise it is a job for an insulation installer.
The big upgrades that move a rating most
Wall insulation. Around a third of the heat lost from an uninsulated home goes through the walls, and wall insulation gives the largest savings of any EPC recommendation. Filling cavity walls is the cheaper route; the Energy Saving Trust estimates it saves around £200 a year. Solid walls can be insulated inside or out, at much higher cost. Wall and floor insulation are jobs for specialist insulation installers, not electricians.
Floor insulation. The Energy Saving Trust estimates floor insulation saves a semi-detached house roughly £55 a year, and a detached house more.
Glazing. Around 18% of an uninsulated home's heat goes through the windows. Replacing single glazing with modern double glazing is a solid improvement where single glazing remains.
Heating system. Replacing an old, inefficient boiler with an A-rated condensing boiler and full controls costs about £3,900 in the Energy Saving Trust's figures. Heat pumps and solar panels also appear in EPC advice. Those, like home batteries, are specialist installations, and we do not fit them.
Getting to EPC band C
Band C matters most to landlords, because in its January 2026 consultation response government decided that privately rented homes in England and Wales will need to reach a C-equivalent standard by 1 October 2030. That is a government decision, not yet law (the legal minimum is still band E), and the detail is in our guide to EPC rules for landlords.
For a typical D-rated house, the path to C usually runs through the fabric first (loft, walls, draughts), then heating controls, then the heating system. Your EPC's recommendations section shows the potential rating if every recommendation were done, which is a good reality check before you spend money. The Energy Saving Trust points out that those recommendations are generated automatically from a national model, so get independent advice before major work.
Make sure the new EPC captures the work
An improvement only counts if the assessor can record it. Once work is done, commission a new EPC rather than waiting for the old one to run out; the Energy Saving Trust notes you can get a new one sooner than the 10-year validity if the home has changed. A fresh assessment after the work is what turns the upgrade into a better band on paper.
To help the assessment reflect the house accurately:
Keep paperwork for cavity or wall insulation, new windows, boilers and heating controls, and have it ready on the day
Make the loft hatch accessible so insulation depth can be checked
Know your electricity tariff; the Energy Saving Trust says the assessor should record, for example, Economy 7 where you have storage heaters
Make sure the heating system's make and model are visible or documented
If you are changing electric heating or adding significant new loads at the same time, an EICR tells you whether the existing installation is in a fit state to take them.
EPC improvement questions, answered
Will the EPC system change soon?
Yes. Government plans new-style EPCs with four headline metrics, and in March 2026 it moved the launch of those reforms to the second half of 2027. Until then, EPCs are produced on the current system and remain valid for 10 years.
Does a better EPC add value to a home?
A better rating usually means lower modelled running costs, which buyers can see on the certificate. How much that adds to price depends on the local market, so treat any headline figure with caution.
Can a tenant improve the rating?
Some small measures, such as LED bulbs, but most improvements need the owner's consent. Landlords have the legal duty to meet the minimum standard.
Booking an EPC
If you have made improvements, or want to know which ones are worth doing, SM Electrical's EPC assessments cover homes across Wolverhampton, Telford, Shropshire and the West Midlands. You can book an EPC with us with the property address and size.
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