How to improve an EPC rating, cheapest measures first

Improving an energy rating is mostly about doing the boring things in the right order. The expensive measures get the attention, but the cheap ones move the score furthest per pound.

24 February 2026 8 min read

First, find out what the model thinks is missing

Your existing certificate lists the fabric and heating of the home element by element, with a rating for each. Anything marked poor or very poor is where the score is being lost. Work through those in cost order rather than starting with whatever is most exciting.

The usual order

MeasureRelative costNotes
Loft insulation top up to 270mmLowFastest payback in most homes with an accessible loft
Draught proofingLowDoors, floorboards, letterboxes, unused chimneys
Heating controlsLowRoom thermostat, programmer, thermostatic radiator valves
Hot water cylinder jacket or top upLowOnly where there is a cylinder
Cavity wall insulationMediumOnly if the walls have an unfilled cavity and are suitable
Floor insulationMediumSuspended timber floors are more practical than solid
Replacement boilerMedium to highWorth doing at end of life rather than early
Double or triple glazingHighComfort gain is real, score gain is modest
Solar PVHighImproves the score and cuts bills where the roof suits it
Solid wall insulationHighestBig gain, big disruption, permissions may apply
Heat pumpHighestBest in a well insulated home. Do the fabric first

Why fabric comes before heating

A heat pump in a leaky, uninsulated house needs a large system and struggles to run efficiently at low flow temperatures. Insulation reduces the heat the building needs in the first place, which makes every heating choice afterwards smaller, cheaper and better performing. Fabric first is not a slogan, it is the order that keeps the eventual bill down.

Measures that need care

  • Cavity wall insulation on an exposed, wind driven rain elevation can cause damp if installed badly. Use an installer with a proper guarantee.
  • Older solid walled homes were built to breathe. Sealing them with the wrong materials moves moisture problems rather than solving them.
  • Spray foam in a loft has caused mortgage and resale problems for some owners. Get advice specific to your roof before considering it.
  • Listed buildings and conservation areas restrict windows, doors and external insulation.

Getting the improvements onto the certificate

The rating only changes when a new assessment is carried out. Keep every invoice, guarantee and installation certificate. An assessor can only record what they can see or what you can evidence, so an undocumented improvement is effectively invisible.

If you are selling or letting, book the new assessment after the work rather than before, and make sure the assessor sees the paperwork on the day.

Landlords and the minimum standard

Under the Minimum Energy Efficiency Standard in England and Wales, most domestic private rented properties cannot be let with an EPC below band E unless a valid exemption is registered. If you own a rental at F or G, that is the first thing to fix, and the exemption route is a last resort rather than a plan.

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