---
title: Retrofit measures overview
stability: figures likely to go stale — savings estimates depend on current energy prices and Energy Saving Trust updates them periodically; check for revised figures before reuse
---

# Common UK home retrofit measures

"Retrofitting" means adding energy-efficiency improvements to an existing home. The measures below are common starting points, usually tackled in the order listed: cutting heat loss before worrying about how efficiently you generate heat.

## Draught-proofing

Draught-proofing seals unwanted gaps around windows, doors and floors, while keeping the ventilation a home still needs. It's usually the cheapest measure: a whole-house professional job costs around £250, less by DIY. Energy Saving Trust estimates it saves around £55 a year in Great Britain for windows, floors and doors, plus ~£45 a year from draught-proofing an unused chimney. It suits almost any home and is a sensible first step.

## Loft insulation

Loft insulation is material (commonly mineral wool) laid across the loft floor to stop heat escaping through the roof — roughly a quarter of an uninsulated home's heat loss. Current guidance recommends 270mm depth. Insulating from scratch costs around £750 in Great Britain; topping up older, thinner insulation costs less, around £600, saving roughly £17 a year at today's prices — more where the starting point is more under-insulated. It suits most homes with an accessible pitched loft; flat roofs, damp lofts and converted lofts usually need a professional.

## Cavity wall insulation

Around a third of heat loss in an uninsulated home escapes through the walls. Homes built from the 1990s onwards typically have a cavity — a gap between inner and outer wall layers — that can be filled with insulating material, usually injected through small drilled holes. It suits cavity walls at least 50mm wide, in good condition, not exposed to flooding or driving rain. A typical installation costs around £2,200 and, per Energy Saving Trust, usually pays for itself within five years. Solid-walled homes (common pre-1930s) need a different, pricier approach not covered here.

## Double and triple glazing

Replacing single glazing with A-rated double glazing cuts heat loss, draughts, condensation and noise; Energy Saving Trust estimates savings of around £85 a year in Great Britain. Triple glazing improves on double glazing further, at extra cost, though the gain is smaller than the single-to-double jump. It suits any home with older or poorly sealed windows, but is one of the pricier measures — and should be fitted by an installer registered with a competent person scheme to meet building regulations.

## Sources

- [Draught proofing — Energy Saving Trust](https://energysavingtrust.org.uk/advice/draught-proofing/)
- [Roof and loft insulation — Energy Saving Trust](https://energysavingtrust.org.uk/advice/roof-and-loft-insulation/)
- [Cavity wall insulation — Energy Saving Trust](https://energysavingtrust.org.uk/advice/cavity-wall-insulation/)
- [Energy efficient windows and doors — Energy Saving Trust](https://energysavingtrust.org.uk/advice/windows-and-doors/)

Facts current as of: 2026-09-20