Which improvements move an EPC rating the most?

Wall insulation, solar PV and a modern, efficient boiler or heat pump tend to move the score furthest. Loft insulation, glazing and heating controls are cheaper wins worth doing first.

Do I need to prove I've made the improvements?

Yes — the assessor records evidence on site (invoices, visible insulation, boiler badges) during the RdSAP survey, so keep paperwork for anything you've had installed.

Free tool

EPC rating improvement checker

Tick the energy measures a property already has and see its likely EPC band plus the next steps that move the rating furthest for the money.

Which of these does the property already have?

Indicative band

Estimated score: 39 / 100

A rough guide only. A real EPC also weighs floor area, fuel type, cylinder insulation and more — only an accredited RdSAP survey produces a certificate you can lodge.

Highest-value next steps

1. Cavity or solid wall insulation
Typical cost: £400–£1,500 cavity · £8,000–£22,000 solid
+16 pts
2. Solar photovoltaic (PV) panels
Typical cost: £5,000–£8,000
+14 pts
3. Air or ground source heat pump
Typical cost: £8,000–£14,000 (grants may apply)
+12 pts
4. Condensing boiler under 15 years old
Typical cost: £2,000–£3,500
+10 pts
5. Loft insulation (270mm+)
Typical cost: £300–£500
+6 pts

This tool gives an indicative band, not a lodged certificate. Only a Domestic Energy Assessor's RdSAP survey can produce an EPC valid for sale or letting.

Background

Why the band depends on more than one thing

An EPC rating is built from a whole property model, not a single feature. Insulation, glazing, heating system, controls and any renewable generation all combine — which is why two similar-looking houses can land on different bands.

Some measures cost little and move the band a step; others are expensive but move it several steps. Loft top-ups and heating controls are usually the cheapest wins, while wall insulation and a heat pump make the biggest structural difference.

This checker gives a rough, indicative band from the measures you tick. It cannot see the property, so it can't replace a survey — the only way to get a rating you can actually use for a sale or letting is an assessor's RdSAP visit.

Trusted on buildings large and small