How to reduce your gas bill in winter

The single biggest saving on this page is free, takes about two minutes, and most households have never heard of it: turning the central heating flow temperature on a condensing combi boiler down to 60C cuts around 9 per cent off the total gas bill. Nesta’s research puts it at 12 per cent of the gas used for space heating, for a household currently running at 80C.

Everything else below is worth doing too. But start with that one.

1. Turn the flow temperature down to 60C

A condensing boiler is called that because it recovers extra heat by condensing water vapour out of its own exhaust gases. It can only do that when the water coming back from the radiators is cool enough. Run the flow at 80C, as a great many boilers are left set from the day they were installed, and the return water never gets cold enough. The boiler stops condensing and quietly runs several percentage points below the efficiency you paid for.

Drop the central heating dial to 60C and it condenses properly again. Your house still reaches the same temperature. It simply takes a little longer to get there, which the timer absorbs.

Two things to get right. The central heating setting is usually separate from the hot water setting, often a second dial or a menu item, and it is the heating one that saves the money. And if you have a system boiler with a hot water cylinder rather than a combi, do not take the cylinder below 60C, because that temperature matters for legionella control.

If the house genuinely will not warm up on the coldest days, put it up in small steps rather than straight back to 80.

2. Use the timer properly, and ignore the myth

Heat your home when people are in it and awake, not around the clock.

The belief that it is cheaper to leave the heating on low all day is the most persistent myth in home heating and it is wrong. A house loses heat to the outside for as long as it is warmer than the air outside. Heating an empty house all day means paying for heat that leaks out of it while nobody benefits. Our myth-busting piece on leaving the heating on goes through the reasoning.

Set it to come on shortly before you get up and shortly before you get home, and to go off about an hour before you leave or go to bed. The residual warmth carries you.

3. Drop the thermostat by one degree

Somewhere between 18C and 21C suits most homes. Every degree you take off cuts the heat your house loses and so the gas you burn.

Try one degree down for a fortnight before deciding. People acclimatise considerably faster than they expect, and a jumper is cheaper than a boiler running an extra hour a day.

4. Heat the rooms you use

A spare bedroom heated to the same temperature as the living room is money going out of the window, literally. Turn the radiator valves down in rooms nobody uses.

Thermostatic radiator valves do this automatically per room, and smart valves let you schedule it. Fitting them across a house is one of the better value upgrades available, and it works with the boiler you already have. See smart heating controls for what we fit, or read how to get control of your heating at home for the full controls picture.

5. Bleed your radiators

If the top of a radiator is cold while the bottom is hot, air is trapped in it. The radiator is heating from only part of its surface, so the boiler runs longer to get the room to temperature.

Bleeding is a fifteen minute job with a radiator key and a cloth, and our guide to bleeding your radiators walks through it. Do it before the heating season, not in the middle of it.

If it is cold at the bottom and hot at the top, that is a different problem: sludge and magnetite settled in the bottom of the radiator. Bleeding will not touch it. That needs a power flush.

6. Get the boiler serviced

An unserviced boiler quietly costs you money all winter. A dirty burner burns badly, a sludged magnetic filter restricts flow, a flat expansion vessel makes the whole system work harder, and none of it announces itself until the boiler stops entirely on a cold morning.

An annual boiler service is £80 fixed with us, takes about an hour, and covers 20 checks. It also keeps the manufacturer warranty valid, which on a boiler still under cover is worth more than the service several times over.

7. Turn the hot water down to 60C

Most boilers are set to heat water hotter than anyone actually uses, and then you dilute it with cold at the tap. Every degree of that is gas you paid for and threw away.

60C is the sensible setting: hot enough to be safe on the cylinder side, cool enough to stop you scalding a child, and it saves gas every single time a tap runs.

8. Insulate, in the right order

Insulation is the only item on this list that keeps paying back for decades, and the order matters because the cheap measures pay back fastest.

Loft insulation first, topped up to a proper depth. Then draught proofing around doors, letterboxes and floorboards, which costs very little and stops a surprising amount. Then cavity walls if the property has them and they are empty. Solid wall insulation is effective but expensive, and is a decision rather than a quick win.

There is little point spending heavily on a new heating system in a house that leaks heat. Fix the fabric first, then size the system to the house you have improved.

9. Check the boiler pressure

Between 1 and 1.5 bar when cold. Low pressure makes some boilers lock out entirely and makes others work harder than they need to.

It takes two minutes to top up with the filling loop. But if you are doing it every few weeks, stop and find the leak, because you are pumping fresh oxygenated water into the system each time and that corrodes it from the inside.

10. Know when the boiler itself is the problem

There is a point where efficiency habits stop being the answer. An old non-condensing boiler can waste over 30 per cent of the gas you pay for. A modern A-rated one wastes under 10.

If your boiler is fifteen years old, no amount of thermostat discipline closes that gap. Our guide to boiler ratings explains the bands, and signs you need a new boiler covers when replacement genuinely pays. If you have been wondering whether to move off gas altogether, we compare the alternatives to a gas boiler honestly, including where a new gas boiler is still the better answer.

Do the free ones this week

Items 1, 2, 3, 4, 5, 7 and 9 cost nothing and can all be done in an afternoon. The flow temperature alone is worth around 9 per cent of your gas bill.

Item 6 costs £80 and protects everything else. If your boiler has not been serviced in the last twelve months, get it booked before the first frost rather than after it, when every engineer in Yorkshire is out on breakdowns.

Book an £80 boiler service online in about two minutes, or call 0800 980 6018 and talk to someone in Bradford.

Flow temperature saving figures from Nesta’s Money Saving Boiler Challenge research, checked 7 September 2026. They assume a condensing combi previously set at 80C.