What is the single biggest saving on a winter energy checklist?

Setting and timing the heating properly. Putting the thermostat to the lowest comfortable temperature, turning it down a degree if you can, and programming the heating around your day saves more than any other single job, and it costs nothing. Heating is the largest slice of a winter bill, so the controls are where the money is.

How do I stop my boiler freezing up in winter?

Lag the external condensate pipe with foam tube. This thin plastic pipe runs outside on most condensing boilers and freezes on the coldest mornings, locking the boiler out just when you need heat most. It is the most common winter breakdown and a length of cheap foam lagging prevents it. Also lag any exposed water pipes in lofts and garages.

Should I leave the heating on while I am away in winter?

Leave it on a low frost-protection setting rather than off entirely. That keeps the house warm enough that the pipes never freeze, which protects you from a burst pipe that would cost far more than the small amount of gas used. You do not need to keep it at normal living temperature for an empty house, just above freezing.

Does turning the boiler flow temperature down really save money?

Yes, on a condensing boiler. Dropping the flow temperature to the low fifties lets the boiler run in its efficient condensing mode, extracting more heat from each unit of gas. It typically saves £50 to £110 over a winter, it costs nothing to change, and it is one of the cheapest efficiency wins available. The radiators run a little cooler, so allow longer warm-up.

When should I do my winter energy preparation?

In autumn, before the first real cold. That gives you time to book a boiler service, catch any fault, and seal draughts and top up insulation while the weather is still mild enough to work in. Doing it before winter means the savings apply across the whole cold season rather than only the second half of it.

Winter energy checklist: an afternoon's work that pays off all winter

Most of a year's energy spending lands in the cold months, so a little preparation in autumn pays off all winter. None of this is dramatic, and most of it costs nothing, but worked through before the first real cold it turns a house that haemorrhages heat into one that holds it. Here is the run-through, roughly in the order worth doing, with the heating controls first because that is where the money is.

The short answer. Set the thermostat to the lowest comfortable temperature and programme the heating around your day. Tune the system by bleeding radiators and dropping the boiler flow temperature to the low fifties. Seal draughts, top up loft insulation, and close heavy curtains at dusk. Lag exposed pipes against freezing. Most of this is free or under a tenner, and together it cuts the winter bill more than any single gadget could.

Set and time the heating

Start where the money is, because heating is the largest slice of a winter bill by a wide margin.

Set the room thermostat to the lowest temperature that is genuinely comfortable, a degree lower than habit if you can manage it with a jumper. Every degree you turn it down trims a noticeable chunk off the heating cost. Our guide to what temperature to set your thermostat walks through finding that point, and thermostat settings covers the controls in detail.

Then programme the heating around your actual day: on shortly before you wake and before you get home, off or set back while you are out and asleep. Turn down the radiator valves in rooms you rarely use so you are not paying to warm empty space, but leave them ticking over low rather than stone cold to avoid damp. This single afternoon of setting the controls properly is the biggest saving on the whole list, and it costs nothing.

Tune the heating system

Before the system works hard all winter, get more heat out of every unit of gas.

Bleed the radiators so they fill with hot water right to the top and warm evenly. Cold patches at the top mean trapped air. Our guide to bleeding radiators shows how.
Clear the radiators. Move furniture and long curtains off them so the heat reaches the room instead of the wall or the back of a sofa. A reflector panel behind a radiator on an outside wall is a cheap extra.
Drop the boiler flow temperature to the low fifties so a condensing boiler runs in its efficient condensing mode. This is one of the cheapest efficiency wins there is, and our boiler flow temperature guide explains exactly how.
Service the boiler if it has not been done in a while. Autumn is the time, both for efficiency and to catch a fault before it leaves you cold in January.

Stop the heat escaping

Now seal the leaks, because there is no point making heat if it walks straight out of the building.

Walk the house on a windy day and feel for draughts around the doors, windows, letterbox, loft hatch, and the gaps around pipes and skirting boards. Seal them with the cheap measures in our draught-proofing guide, leaving the deliberate ventilation alone so you do not trap moisture.

Check the loft insulation is at full depth and top it up if the joists are showing, since the loft is where most heat is lost in an under-insulated house. The loft insulation guide covers the recommended depth. Finally, hang or close heavy lined curtains at dusk to keep the day's warmth in. Together these make the house feel warmer at a lower thermostat setting, which is where the heating saving actually comes from.

Protect against the freeze

A cold snap can cost far more than a high bill if a pipe bursts, so spend a little time on resilience.

Lag exposed water pipes in unheated lofts, garages and outbuildings with cheap foam tube. The pipe lagging guide covers what to buy.
Insulate the boiler's external condensate pipe. This thin plastic pipe can freeze on the coldest mornings and lock the boiler out just when you need it most. A length of foam lagging prevents the most common winter breakdown there is.
Know where your stopcock is and that it turns, so you can shut the water off fast if a pipe does go.
If you are away, leave the heating ticking over on a low frost-protection setting rather than off entirely, so the house never drops to the point where pipes freeze.

The maths here is one-sided. Frost-protection heating for a week away might cost a few pounds in gas. A burst pipe in a freeze can flood ceilings and floors and run to thousands, on top of the disruption of putting it right. This is the one item on the list where the saving is not the point: you are buying insurance against a much larger bill, and the premium is tiny.

Sort the hot water and the smaller stuff

With the big items done, tidy up the rest.

If you have a hot-water tank, fit or check the cylinder jacket and lag the nearby pipes so stored hot water stays hot for longer. Turn the cylinder thermostat to around 60C, hot enough to be safe against bacteria but no hotter than needed. Our hot water savings guide has the detail.

Swap any remaining old bulbs for LEDs, which matters more in winter when the lights are on far longer. Check the seals on the fridge and freezer while you are at it. And if you dry washing indoors over winter, the drying without a tumble dryer guide helps you do it without running up condensation and damp.

One winter habit worth breaking is reaching for a plug-in electric heater to take the chill off. At 26.11p per kWh a 2kW heater costs about 52p an hour, well over double the gas it would take to warm the same space, so it is a false economy in any home with working central heating. Heat the person instead, with a jumper, a hot-water bottle or an electric blanket at a few pence an hour, and let the gas do the room.

What it all adds up to

Here is roughly what each job costs to do and what it tends to be worth over a winter, so you can see why the order above is what it is.

Job	Cost to do	Typical winter saving
Set and time the heating, turn down 1C	£0	£60 to £100
Drop boiler flow temperature	£0	£50 to £110
Bleed and clear radiators	£0	worth it, varies
Draught-proofing	£10 to £40	£30 to £60
Top up loft insulation	varies	£40 to £120
Lag pipes and condensate	under £20	avoids a burst pipe

At 26.11p/kWh electricity and 7.33p/kWh gas, Ofgem cap July to September 2026. Savings are typical ranges and depend on your house, habits and how cold the winter is.

Almost everything here is free or under a tenner, and the only one that pays back over years rather than weeks is insulation. Work down the list once in autumn and the house holds heat all winter for almost nothing. For the year-round version, see the summer energy checklist, and for the single best small buys, our quick wins under a tenner. The main home heating hub ties the heating jobs together.