How do I reduce my energy bills?

The changes that reduce household energy use most, ordered by impact per pound spent — from free behaviour changes to worthwhile insulation.

Difficulty: beginner
Time: 3 hr
Read: 3 min

Short answer

Start with the free changes: heating controls set correctly, thermostat down a degree, draught-proofing, and turning the heating off in unused rooms. Then insulation, in order of payback: loft, then hot water tank, then walls. Heating is usually the majority of a household energy bill, so that's where the savings are.

Energy advice tends to be a long undifferentiated list. In practice, space heating dominates most household bills, so measures that reduce heat demand matter far more than switching off standby lights. The order below reflects that.

What you'll need

Draught excluder strip (optional)
Radiator thermostatic valves (optional)
Smart or programmable thermostat (optional)

Step by step

Check your heating controls are actually set correctly.Many homes heat empty houses all day, or run the boiler flow temperature far higher than needed. This costs nothing to fix and often saves a lot.
Turn the thermostat down by one degree.Widely cited as saving a meaningful percentage of heating costs, and usually barely noticeable in comfort.
Draught-proof doors, windows, letterbox and loft hatch.Cheap, quick and effective. Never block air bricks or vents serving fuel-burning appliances — see the draughts guide.
Fit thermostatic radiator valves and turn down radiators in unused rooms.Heating rooms nobody uses is one of the most common avoidable costs.
Check loft insulation depth and top it up to current recommendations.Around 270mm of mineral wool. Loft insulation has among the shortest paybacks of any measure.
Insulate the hot water tank and exposed pipework if you have them.A tank jacket is inexpensive and pays back very quickly.
For a combi boiler, check the flow temperature — many are set far higher than necessary.Reducing it can improve condensing efficiency. Look up guidance for your specific boiler, or ask an engineer.
Take shorter showers and run appliances on eco cycles with full loads.Water heating is typically the second-largest energy use after space heating.
Then look at bigger measures — cavity wall or solid wall insulation, glazing — with actual payback figures.These are real improvements but the payback periods are long. Do the cheap things first.

Tips

Check whether you're eligible for any insulation grants or schemes before paying full price — availability changes, so check current government guidance.
A smart thermostat helps mainly by making it easy to not heat an empty house. If your existing controls already do that well, the saving is smaller than advertised.
Heavy curtains closed at dusk genuinely reduce heat loss through windows, and cost nothing to use.
Compare tariffs periodically. The savings vary a great deal with market conditions, so it's worth checking rather than assuming.

Common mistakes

Focusing on standby power first — It's real but small. Heating dominates most bills, so start there.
Blocking vents while draught-proofing — Causes condensation and, near fuel-burning appliances, a carbon monoxide risk.
Turning heating fully off when out all day — In a poorly insulated house, reheating from cold can cost as much as maintaining a low background temperature, and it causes condensation.
Paying for expensive measures before the cheap ones — Draught-proofing and loft insulation have far shorter paybacks than glazing or wall insulation.

Questions people ask

Is it cheaper to leave the heating on low all day?

It depends on the house. In a well-insulated home, heating only when needed is generally cheaper. In a poorly insulated one, a low background temperature can avoid expensive reheating and reduce condensation. Try both and compare meter readings.

What has the fastest payback?

Draught-proofing and loft insulation are consistently among the quickest, often paying for themselves within a couple of years. Correct heating controls cost nothing at all.