For decades, households were told to keep the thermostat at 19°C to save money and energy. Yet modern housing, home working and changing health advice are rewriting the script on what a “good” indoor temperature really is.
Where the 19°c rule came from – and why it no longer fits
The famous recommendation to cap heating at 19°C is not some universal comfort law. It was born in the 1970s oil crisis, when governments pushed households to turn down the heat to spare scarce energy supplies.
At that time, homes were badly insulated, single-glazed and draughty. Heating systems were often inefficient and poorly controlled. The priority was cutting national fuel consumption, not fine‑tuning how people actually felt in their living rooms.
Fast forward to today and the context is completely different. Building regulations now require far stronger thermal performance. Windows are typically double- or triple-glazed. Boilers and heat pumps squeeze more warmth from each unit of energy. Smart thermostats can switch radiators on and off room by room.
Daily life has shifted too. More people work from home, spend long hours sitting in front of screens, and expect their home to double as office, gym and relaxation space. Sitting still in a cool room feels much colder than walking around a shop or commuting.
The old 19°C target was designed for an era of leaky homes and emergency fuel savings, not for modern lifestyles and health standards.
Energy experts increasingly argue that the 19°C figure should be treated as a guideline, not a strict rule. For many households, it simply does not match their real comfort needs, especially for children, elderly people or anyone with health vulnerabilities.
Why 20°c is emerging as the new sweet spot
Across Europe, specialists in building physics and heating systems are converging on a new reference point: around 20°C for main living areas.
That single extra degree above 19°C might sound trivial. In practice, it can transform how a room feels, especially when you are sitting still, working, or relaxing on the sofa.
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Energy cost: the extra degree that stays manageable
Raising the thermostat does come at a price. A widely accepted rule of thumb is:
- Each extra degree above 19°C increases heating energy use by roughly 7%.
Going from 19°C to 20°C is therefore a modest step. Jumping to 22–23°C is another story entirely, with bills rising sharply for every extra notch.
Around 20°C strikes a compromise: warmer and more comfortable than 19°C, but still far from the costly, overheated homes that send bills soaring.
Comfort: why many people feel cold at 19°c
Thermal comfort is not just about a number on the thermostat. It depends on how heat is produced, stored and felt in the room. Three factors matter a lot:
- Insulation: poorly insulated walls and single glazing create cold surfaces. Even at 21°C, you can feel chilly if you are sitting next to a freezing window.
- Humidity: damp air makes cold feel harsher, especially in winter. A home at 19°C and high humidity can feel far less comfortable than 20°C with balanced humidity.
- Activity level: working at a laptop or watching TV generates little body heat. The same person may feel fine at 19°C while cleaning the house, but shiver at that temperature when working from home all day.
This is why many specialists now treat 20°C as a realistic reference, not a luxury. For a lot of people, especially those spending long hours seated, it is simply the point where “a bit fresh” becomes comfortably warm.
Different rooms, different temperatures
One of the biggest shifts in heating advice is the move away from a single temperature for the whole home. Experts now recommend tailoring the setting to how each room is used.
| Room | Recommended temperature | Reason |
|---|---|---|
| Living room / office | Around 20°C | Comfort for sitting, working, relaxing |
| Bedrooms | 16–18°C | Supports better sleep and air quality |
| Bathroom (when used) | Around 22°C | Warmth when undressed and stepping out of the shower |
| Hallways / corridors | Around 17°C | Limited time spent there, less need for full comfort |
This strategy allows households to redirect heat where it genuinely matters. Bedrooms stay slightly cooler, which many sleep specialists favour, while living areas feel cosy without requiring a uniform, higher temperature everywhere.
Simple moves that make 20°c feel warmer
Getting the thermostat to 20°C is only half the story. How you manage your home can make that 20°C feel much warmer – or much colder.
- Use a programmable or smart thermostat: set it to lower the heat at night or when you are out, and to raise it just before you wake up or return home.
- Improve insulation where you can: sealing gaps around windows and doors, insulating loft spaces and adding thick curtains can significantly cut heat loss.
- Let the sun work for you: open shutters and curtains on sunny winter days, then close them as soon as night falls to trap the heat.
- Close doors between zones: keep warmer rooms separated from cooler corridors to avoid losing heat.
- Use rugs and soft furnishings: carpets and rugs reduce cold coming from floors and make rooms feel warmer at the same air temperature.
According to France’s ADEME energy agency, basic efficiency measures can trim heating bills by 10–15% without touching the thermostat setting.
How cold is too cold? the health line you should not cross
In times of high energy prices, some households are tempted to push the thermostat far below 19°C to save money. Health authorities warn that this strategy carries real risks.
The World Health Organization suggests a minimum of 18°C in main living areas for healthy adults, and higher temperatures for older people, infants or anyone with chronic conditions.
- Respiratory problems: prolonged exposure to chilly indoor air can irritate airways, worsen asthma and increase the risk of infections.
- Cardiovascular strain: when the body is cold, blood vessels constrict and the heart works harder to maintain core temperature, which is especially risky for older adults or people with heart disease.
- Poor sleep and fatigue: very cold rooms may make it harder to fall asleep and stay asleep, especially for children or those with existing health issues.
Below that 18°C mark, the potential savings on your bill need to be weighed against the hidden costs for health and wellbeing, which can be far higher in the long run.
The new energy reality: comfort versus climate and cost
Debates about 19°C or 20°C are part of a broader shift in how we think about heating. Households are navigating three pressures at once: keeping energy bills under control, cutting carbon emissions, and staying physically comfortable at home.
Heat pumps, better insulation and rooftop solar are reshaping the technical side of heating. At the same time, public campaigns are nudging people toward “energy sobriety”: using heat where it counts, rather than constantly running radiators at high power in every room.
The real question is no longer “What number should be on the dial?” but “How can I heat smartly, room by room, hour by hour?”
What “ideal temperature” really means in practice
The phrase “ideal temperature” can be misleading. There is no single magic figure that works for every person and every building. Instead, think in terms of a comfort band and personal adjustments.
- For most healthy adults: living areas between 19°C and 21°C usually feel comfortable.
- For young children, elderly people or those with health issues: aiming closer to 20–21°C in main rooms is often safer.
- For people who feel cold easily: adding layers of clothing can allow slightly lower thermostat settings without discomfort.
Imagine two neighbours in identical flats, each set at 20°C. One works from home in a T‑shirt, rarely moves and feels chilly all day. The other wears a jumper, moves around regularly and feels perfectly fine. The number on the wall is the same, but their comfort strategies are not.
Key terms and real-life scenarios
Two technical concepts often mentioned in this debate are worth clarifying.
- Thermal inertia: how slowly a building heats up and cools down. A heavy stone house may hold heat for hours after the boiler stops, while a lightweight flat above a garage cools quickly.
- Setback temperature: the lower temperature you choose at night or when you are away. Dropping from 20°C to 17°C for several hours can deliver notable savings without making the home uncomfortably cold when you return.
Consider a typical winter weekday in a reasonably insulated home:
- 06:00–08:00 – thermostat rises from 17°C to 20°C so the kitchen and living room are warm for breakfast.
- 08:00–17:00 – living areas held at 17–18°C while the house is empty, bedrooms cooler still.
- 17:00–22:30 – living room and home office at 20°C during family time and remote work.
- Night – setback to 17°C in living spaces, 16–18°C in bedrooms.
Over a season, that schedule can keep comfort high while avoiding the heavy costs of holding 21–22°C around the clock. The thermostat number changes, but comfort remains stable because timing, zoning and simple habits work together.
The era of a single nationwide figure is fading. The real “ideal temperature” sits around 20°C for living spaces, adjusted room by room and backed by smart, thoughtful heating habits.