For decades, the old 19°C rule has been wheeled out as the “right” temperature. Today, energy specialists say that one-size-fits-all target no longer matches how we live, work and heat our homes.
The 19°C rule belongs to another era
The 19°C benchmark did not come from medical research or comfort science. It was born during the oil crises of the 1970s, when governments and energy providers were desperate to curb consumption. At the time, most homes were poorly insulated, often draughty, and equipped with basic boilers or electric heaters.
In that context, 19°C looked like a pragmatic compromise between comfort and savings. But the housing stock has changed. Double and triple glazing, insulated walls and roofs, heat pumps, underfloor heating and smart thermostats have rewritten the rules of indoor climate.
A single “ideal” temperature no longer makes sense in modern, better-insulated homes with very different uses from room to room.
Energy experts now say clinging to 19°C as a universal rule can leave people feeling cold, especially during long sedentary periods such as working from home. That discomfort often leads to inefficient habits: plugging in electric space heaters, covering radiators with drying racks, or opening windows wide because one room overheats while others stay chilly.
Why 20°C is becoming the new reference
The new consensus forming in Europe’s energy circles is simple: for main living areas, 20°C is a more realistic reference temperature than 19°C.
At 20°C, most people feel comfortable when sitting, reading, watching TV or working on a laptop. The body maintains its core temperature more easily, and people tend to move less just to stay warm. That matters in winter when many of us spend hours motionless in front of screens.
Humidity and air movement also shift the balance. A dry, slightly draughty room at 19°C can feel unpleasantly cold. A well-sealed room at 20°C with balanced humidity feels noticeably more comfortable, even if the number on the thermostat is only one degree higher.
For most households, 20°C in living spaces offers a better balance between comfort, health and controlled energy use.
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There is a building-health angle too. Homes kept too cool for long periods can suffer from condensation on windows and cold surfaces. That moisture then feeds mould growth, especially in corners and behind furniture. A slightly higher and more stable temperature, combined with regular ventilation, helps limit that risk.
The end of one temperature for the whole home
Experts no longer talk about “the” right temperature for a flat or house. Instead, they promote a room-by-room strategy based on how each space is used and at what time of day.
Recommended temperatures by room
| Room | Recommended range | Main benefit |
|---|---|---|
| Living room / home office | 20°C | Comfort for sedentary activities |
| Bedrooms | 16–18°C | Better sleep quality |
| Bathroom | Around 22°C when in use | Less thermal shock when showering |
| Hallways and corridors | About 17°C | Limits heat loss while saving energy |
Living rooms and open-plan kitchen areas tend to be where people spend the most waking hours. That is where the 20°C reference applies. Bedrooms, on the other hand, generally benefit from cooler air. Many sleep studies suggest people fall asleep more quickly and wake less often when room temperatures sit below 19°C.
The bathroom is the exception. A warm space – around 22°C during use – reduces the unpleasant shock of stepping out of a hot shower into cold air. Keeping that warmth limited to the times when the bathroom is in use avoids unnecessary energy waste.
Think of your home as a series of microclimates, each tailored to what you actually do in that space.
How smart heating tech changes the game
The shift away from a single temperature rule is closely linked to technology. Older systems often had one thermostat in a hallway controlling every radiator. Today, smart thermostats and connected valves allow much finer control.
- Digital thermostats set different targets by room and time of day.
- Smart radiator valves reduce heat in empty rooms automatically.
- Apps show real-time use, nudging households towards more efficient patterns.
Manufacturers claim that such systems can cut heating bills by up to around 15% when used correctly. The maths is not entirely straightforward, though. Raising the temperature in a living room by one degree can, in theory, increase consumption by about 7%. Yet better comfort may mean fewer people resort to energy-hungry electric heaters or leave windows wide open because a single thermostat overheats part of the home.
In other words, a slightly warmer but well-managed home can cost less to run than a cooler home heated in a crude, all-or-nothing way.
Balancing energy bills, comfort and climate goals
Households across Europe and North America are torn between two pressures: rising energy prices and calls to cut emissions. The 20°C guideline does not mean turning homes into saunas. It means aiming for realistic, stable comfort while using technology and behaviour to remove waste.
Several strategies help square that circle:
- Lower temperatures at night in living rooms, while keeping bedrooms cool but not freezing.
- Reduce heating in unused rooms instead of the whole property.
- Use timers so the bathroom is warm only when people are likely to shower.
- Combine modest clothing layers with stable indoor temperatures rather than jumping between extremes.
Small changes in building fabric also have strong effects. Sealing draughts around windows and doors, adding thick curtains, or fitting reflective panels behind radiators can all improve the perceived warmth without touching the thermostat.
What “thermal comfort” really means
Experts talk less about temperature and more about “thermal comfort”. The term brings together several factors: air temperature, humidity, radiant heat from walls and windows, air movement and clothing.
A classic example: a person sitting near a single-glazed window may feel chilly at 20°C because the cold glass radiates heat away from their body. In a well-insulated room with warm walls and no draughts, the same 20°C feels far more pleasant. That is why two homes, both set to the same number, can feel completely different.
Activity level plays a role too. Someone cooking, cleaning or exercising produces their own heat and can tolerate cooler air. Someone sitting still at a laptop in a poorly heated home needs a slightly higher room temperature or more clothing to feel the same comfort.
Real-life scenarios: what changing from 19°C to 20°C looks like
Take a medium-sized flat heated mainly in the evening and weekend. The thermostat is currently set to 19°C across the board. The occupants often complain of feeling cold in the living room and use a small electric heater during film nights.
They switch to a smarter strategy: 20°C in the living room between 5 pm and 10 pm, 17°C in the hallway, 16–17°C in bedrooms at night, and 22°C in the bathroom only for two short morning and evening time slots. They remove the electric heater and stop opening windows just to cool an overheated corridor.
The gas or central heating boiler runs slightly more for the living room, but less for other rooms. The electric heater disappears from the bill. Comfort rises, humidity stabilises, and the overall cost difference narrows more than the simple “+7% per extra degree” rule would suggest.
Risks of underheating and overheating
Sticking dogmatically to 19°C can cause its own problems. Very cool homes can push vulnerable people, such as the elderly or those with respiratory illnesses, into unsafe territory. Prolonged damp and cold increases the risk of mould and exacerbates conditions like asthma.
The other extreme brings costs and climate impacts. Keeping a home at 22–23°C all winter burns energy and drives up emissions, especially in properties still heated with gas or oil. The new guidance tries to chart a realistic middle path: a touch warmer than the 1970s target in key spaces, cooler where warmth is less crucial, and smarter control across the board.
For households, the question shifts from “Should I stick to 19°C?” to “Where does 20°C make sense, and where can I go lower without losing comfort or health?” That more nuanced approach matches modern housing, modern tech, and the way people actually live in their homes today.