What Temperature Should Your Home Be? Thermostat Settings That Save Money

One degree on the thermostat can be worth around £90 a year, so the temperature you choose matters more than almost any other energy decision. But what should you actually set it to? The answer, according to the Energy Saving Trust, is that most homes can be comfortably warm between 18°C and 21°C — and within that range, every degree lower saves money. This guide explains the recommended settings for different rooms, for different people, and for the times when heat matters most to health.

The short answer: 18°C to 21°C for living areas

The Energy Saving Trust’s heating guidance is clear: aim for 18°C to 21°C in the rooms you use most, with around 18°C being perfectly comfortable for many healthy adults in everyday clothing. MoneySavingExpert puts it similarly, noting that your heating bill rises by roughly 10% for every degree you turn the thermostat up — which is why turning down by just 1°C, if you are currently above 21°C, is estimated to save around £90 a year in a typical home in Great Britain.

The World Health Organization (WHO) takes a health-led view that lines up with those figures. Its housing and health guidance sets 18°C as a safe and well-balanced indoor temperature for healthy, appropriately dressed people in cold seasons, and its review found little evidence of health risk for most healthy adults in that population between 18°C and 24°C. The WHO instead fixes 18°C as a strong recommendation — a minimum for the general population — and notes there may be no risk or benefit in keeping homes between 18°C and 24°C, even though warmer settings cost more.

So: if you are a healthy adult, treat 18°C as your starting point and nudge up only if you feel cold. If you are used to 22°C or 23°C, come down in half-degree steps over a few days rather than all at once — you will barely notice, and your boiler will.

What temperature for each room?

Heating every room to the same temperature wastes money. Using thermostatic radiator valves (TRVs) where you have them, a sensible pattern looks like this:

• Living room: 18–21°C. The room you sit in stillest needs to feel warmest; this is also where most main thermostats sit.
• Bedrooms: around 18°C, and cooler is fine for many adults. MoneySavingExpert notes that sleeping in a cooler room is generally better for sleep, and the WHO’s 18°C minimum is about occupied, waking hours, not a target for under the duvet.
• Bathroom: slightly warmer is pleasant and helps dry the room out — use the extractor fan and short bursts of heat rather than keeping it hot all day.
• Hallways and unused rooms: turn TRVs down low, but not off. The Energy Saving Trust warns that a completely off radiator all winter can cause damp and condensation in that room.
• Home office: 18–20°C. If you work from home, warming the room you sit in — and the person, with layers — beats heating the whole house, as in our 20 ways to cut your energy bill this winter.

If your only thermostat is in the hallway, be aware that hallways are often cooler than living rooms, so a setting of 18°C there may mean 19–20°C where you sit. Room thermometers cost a few pounds and settle a lot of arguments.

What if someone in the home is vulnerable?

The 18°C guidance comes with an important caveat: it applies to healthy adults. The Energy Saving Trust notes that there is guidance on minimum temperatures for different groups, and that the main room should be warmer for the elderly and for people who are ill or have limited mobility — bodies that generate less heat and move less need warmer air. Babies need the opposite care: their rooms should not be overheated, and a room thermometer helps keep them in a safe, comfortable range.

NHS winter guidance encourages people who are older or have health conditions that are worsened by cold to keep their homes warm, to seek help early if they feel unwell in cold weather, and to check the benefits and grants they may be entitled to. If in doubt for a specific condition, ask a health professional rather than an energy guide.

How cold is too cold for the building?

People are not the only consideration. Mould and condensation thrive in cold, damp homes: the government guidance on damp and mould in rented homes from Awaab’s Law explains that everyday activities like showering and cooking produce large amounts of moisture, and that when condensation forms on cold surfaces it can quickly lead to mould. Ventilation matters too — extracting moist air while showering and cooking, and airing rooms, protects both health and the property.

For pipes, the simplest protection is never letting the house get truly cold: when you go away in winter, leave the heating on low or use your thermostat’s frost-protection setting (often around 5–7°C) so pipes do not freeze, rather than switching the boiler off completely.

Night-time and when you are out

There is little benefit to heating an empty or sleeping house to daytime temperatures. Use your programmer or a smart thermostat schedule so the heating comes on shortly before you wake or return, and goes off a while before bed — radiators and rooms hold heat, so homes stay comfortable as the system winds down. At night, most adults sleep better in a cooler bedroom, so a setback to around 16–18°C, or simply off with a morning warm-up timed, works well for many households. Do experiment: homes differ in how fast they cool, and an older, leakier property may need gentler setbacks than a well-insulated one. Insulation itself slows the cooldown — see our guides to loft insulation and cavity wall insulation for the two biggest upgrades.

Thermostat myths worth dropping

“Turning the thermostat up high heats the house faster.” It does not. A thermostat is a limiter, not an accelerator: set to 25°C, your boiler heats at the same rate, then overshoots to a temperature you did not need and will pay for.

“Leaving the heating on low all day is cheaper than switching it on and off.” For most homes, no — you end up heating an empty house for hours. The exception is some heat pump systems, which run more efficiently at low, steady output; follow your installer’s advice there.

“One degree makes no difference.” At roughly £90 a year and around 9–10% of a typical heating bill per degree, one degree is the single best-value change most households can make without spending anything.

Frequently Asked Questions

What is the best temperature to save money but stay comfortable?

For most healthy adults, 18°C is the sweet spot the Energy Saving Trust, MoneySavingExpert and WHO guidance converges on; anywhere in the 18–21°C range is reasonable, and each degree lower saves money.

Is 18°C too cold for elderly people?

It can be. Guidance suggests the main living room should be warmer for older people and those who are ill or less mobile. NHS winter advice is to keep homes warm and check for support; do not apply the 18°C target to vulnerable household members without considering their needs.

What temperature should a baby’s room be?

Comfortable and not overheated — treat 18°C as a guide and use a room thermometer, adjusting bedding and clothing rather than cranking up the heating.

Should I turn the heating off completely on holiday?

No. Use frost protection or a low setting around 5–7°C so pipes do not freeze and burst, which would cost far more than the heating you saved.