EPC improvement measures, in plain English
Fabric first is the order that usually wins: stop heat escaping, then control the heating you still need, then look at generation. Here is every measure in the planner, cheapest first.
Smart heating controls & LED lighting — £100-£250 (indicative)
Programmer, room thermostat, thermostatic radiator valves and LED bulbs throughout.
Indicative range for a smart thermostat / controls and LED swap. Indicative — varies by property; source checked 30 Oct 2026, see About.
Draught proofing — £150-£250 (indicative)
Seal gaps around windows, doors, floors and chimneys.
Indicative EPC cost range for draught proofing. Indicative — varies by property; source checked 30 Oct 2026, see About.
Loft insulation top-up (to 270mm) — £600-£900 (indicative)
Top up loft insulation to the recommended 270mm depth.
Energy Saving Trust typical: around £600 to top up, around £900 from scratch for a semi-detached house. Indicative — varies by property; source checked 30 Oct 2026, see About.
Cavity wall insulation — £1,500-£2,700 (indicative)
Fill the cavity in external walls — only where a survey says the walls are suitable.
Energy Saving Trust typical: around £1,500 terraced to £2,700 semi-detached; detached homes can be higher. Indicative — varies by property; source checked 30 Oct 2026, see About.
Double glazing — £4,500-£6,000 (indicative)
Replace single glazing with double glazing.
Indicative EPC cost range for double glazing; whole-house quotes vary widely. Indicative — varies by property; source checked 30 Oct 2026, see About.
Heating upgrade — air source heat pump — £4,500-£12,000 (indicative)
Replace an old boiler with an air source heat pump. Grant support may reduce the net cost.
Around £12,000 typical before grant (DESNZ average data); the £7,500 Boiler Upgrade Scheme grant can bring the net cost down for eligible homes, hence the wide range. Indicative — varies by property; source checked 30 Oct 2026, see About.
Solar panels (solar PV) — £6,500-£9,000 (indicative)
Rooftop solar PV, typically around 3.5kWp for an average home.
Energy Saving Trust average domestic system around £7,000 for about 3.5kWp. Indicative — varies by property; source checked 30 Oct 2026, see About.
Measures we deliberately do not price
Solid wall insulation, floor insulation and whole-house glazing replacements vary so much by construction and size that a single range would mislead more than it helped. If your EPC recommends them, get quotes — and remember that for landlords, spending counts towards the £10,000 cap whether or not the home reaches C.