How to improve your EPC rating
Start with the recommendations list on your current certificate: it is calculated for your actual house. This guide covers what each common measure typically costs and how much score it tends to buy.
The cheap wins first
Low-energy lighting costs a few pounds a bulb and every assessor checks it. Swap the lot before the assessment.
Loft insulation is the classic. Topping up from nothing to 270mm typically costs £400 to £1,200 fitted, and on an uninsulated house it can move the score by several points. If you already have a thick layer, topping it up adds little.
Hot water cylinder jacket and heating controls: a jacket costs about £20; adding a room thermostat and radiator valves typically runs £350 to £600. Small individually, but they add up.
The structural measures
Cavity wall insulation typically costs £1,000 to £3,000 for a house and pays back fast if your walls qualify. Solid walls are a different story: internal or external insulation runs well into five figures and usually only makes sense during a bigger renovation.
Double glazing helps comfort more than score. The assessment gives it fewer points than people expect, so treat it as a window decision, with the EPC as a bonus.
Heating and renewables
A modern condensing boiler (£2,000 to £4,000 installed) lifts an old-boiler home noticeably. A heat pump costs more (£7,000 to £14,000 before support; a government grant currently covers a large slice in England and Wales) and its effect on the score has improved as the assessment method has been updated to reflect electricity’s falling carbon intensity. Solar panels (£5,000 to £8,000) reliably add points and pair well with either.
A sensible order
- Lighting, cylinder jacket, draught-proofing: under £200 all in.
- Loft top-up and heating controls.
- Cavity wall insulation, if your walls have cavities.
- Boiler replacement when the old one is near end of life.
- Solar or a heat pump if you are aiming for B, or planning to stay long term.
Before you book the new assessment
Keep every invoice and certificate: assessors can only credit what they can evidence, and insulation hidden in a wall needs paperwork. Once the work is done, a new assessment (see what an EPC costs) replaces your old rating immediately; you never have to wait for the old certificate to expire.
Prices above are typical ranges for an average house, not quotes. Get at least two, and check whether your council or energy supplier runs a support scheme before paying full price for insulation.