The average UK home can save £200 to £400 a year on gas with the changes below. Most cost nothing. Each tip lists the spend, the saving, and the payback in plain numbers.
£130 to £230 a year
Tips 1, 2, 5 combined. No spend.
£215 to £430 a year
Tips 3, 4, 8 combined. Under £750 spend, payback 1 to 3 years.
£450 to £750 a year
Tips 6, 7, 9 combined. Insulation plus boiler upgrade.
Free
£60 to £100 a year
Instant
On combi boilers, drop the heating flow dial to around 60°C (the central position on most). Below 60°C the boiler stays in condensing mode for longer, capturing more energy from the flue gases. Set hot water to 60 to 65°C to keep above the legionella threshold. Most homes notice no comfort difference.
Free
£50 to £80 a year
Instant
20°C suits most living spaces. Each 1°C reduction cuts heating demand by 5 to 8%. Combine with thermostatic radiator valves and you can keep bedrooms cooler still without freezing the rest of the house.
£150 to £300
£75 to £150 a year
2 to 3 years
Thermostatic radiator valves let you set different temperatures per room. Bedrooms at setting 2 to 3, living spaces at 4. The Energy Saving Trust estimates 10 to 15% of heating spend can be reclaimed where TRVs replace plain valves.
£150 to £250
£100 to £200 a year
1 to 3 years
Hive, Nest, Tado and Drayton Wiser learn your schedule and only heat when you are home or returning. Geofencing turns the boiler off when the last person leaves and on before they return. Best value when paired with TRVs.
Free
£20 to £50 a year
Instant
Air trapped at the top of a radiator creates cold spots and forces the boiler to work harder. Bleed any radiator with cold patches at the top. Five minutes per radiator, no tools beyond a bleed key.
£300 to £500
£150 to £200 a year
2 to 3 years
If your loft has under 100 mm of insulation, topping up to 270 mm is the highest-impact insulation upgrade per pound spent. DIY rolls cost £200 to £350 in materials, plus a Saturday. ECO4 sometimes covers it for free if you qualify.
£400 to £800
£100 to £150 a year
4 to 7 years
If your home was built between 1920 and 1990 and has unfilled cavity walls, this is one of the bigger paybacks available. A surveyor drills small holes, blows in beads or mineral fibre, then patches the holes. One day's work for a typical 3-bed semi.
£50 to £200
£40 to £80 a year
1 to 4 years
Self-adhesive seals around door frames, brush strips at letterboxes, sash window strips, chimney balloons in unused fireplaces. DIY-friendly, payback in heat alone usually under 3 years.
£1,800 to £3,500
£200 to £400 a year (vs band F or G)
5 to 12 years
Replacing a 20-year-old non-condensing boiler with a modern A-rated condensing model cuts gas use by roughly a third on a 3-bed semi. Less worthwhile if your existing boiler is already band B or C and under 10 years old.
£80 to £120
Prevents £100 to £300 in efficiency loss
Year 1
A serviced boiler runs at peak efficiency. An untouched boiler can lose 5 to 15% efficiency over 3 years from soot and combustion drift. Annual servicing is also a warranty condition for almost every UK manufacturer.