Heating: The 19°C rule is outdated; here is the new expert recommendation.

Winter may have arrived, but energy experts say one long-standing piece of advice about keeping warm at home is overdue for an update: the “19°C rule” is no longer seen as the best balance between comfort and energy use. Newer studies and the way people now live and work indoors are driving a shift towards a more flexible, room-by-room approach - with 20°C increasingly treated as the benchmark for living spaces.

For decades, setting the thermostat to 19°C has been widely promoted as a sensible standard. However, specialists in energy efficiency now argue that a single fixed temperature cannot suit every home or every room, and that better-insulated properties and smarter heating controls make more tailored settings both practical and cost-effective.

Why the long-standing 19°C guideline is being challenged

The 19°C recommendation emerged in the aftermath of the 1970s oil crisis, when cutting fuel consumption was an urgent priority and many homes were far less energy-efficient than they are today. Properties often had poorer insulation, heating systems were less responsive, and household routines looked very different.

Nick Barber, an energy management expert, says the figure was intended primarily as an economic compromise rather than a true “comfort optimum”. In other words, it was a rule of thumb designed to curb costs, not a one-size-fits-all standard for modern living.

With improvements in building standards and the growth of home energy retrofits, experts say households can now manage indoor temperatures more precisely - and that the old target no longer reflects what most people need for day-to-day comfort.

20°C becomes the reference point for main living areas

Although the change sounds small, specialists say moving from 19°C to 20°C can make a noticeable difference, particularly for people spending long periods sitting still - for example while working from home, reading, or watching television.

Brad Roberson, a heating systems specialist, notes that thermal comfort depends on far more than the number on the thermostat. Factors such as humidity, draughts and air movement, activity levels, and clothing all shape how warm a room feels.

Recent research suggests that at around 20°C, the body can more easily maintain its core temperature of 37°C, especially during sedentary activities. Experts also point to another practical benefit: keeping homes too cool can increase the likelihood of condensation and mould, problems commonly associated with underheated rooms.

A “zoned” strategy: setting temperatures by room and use

Rather than chasing a single ideal number for the whole house, energy professionals are increasingly advocating heating that reflects how each room is used:

• Living rooms and main occupied spaces: around 20°C for everyday comfort
  
• Bedrooms: typically 16–18°C, a range often considered better for restful sleep
  
• Bathrooms: about 22°C to reduce the discomfort of stepping out of a shower into cold air
  
• Hallways and other transitional areas: roughly 17°C is often sufficient
  

Experts say this approach can improve comfort where it matters most while avoiding unnecessary heating in less-used spaces.

Smart controls can cut bills while improving comfort

Modern heating technology is making this more targeted approach easier to achieve. Connected thermostats and smart radiator controls allow households to schedule different temperatures for different rooms and times of day, helping ensure heat is delivered where and when it is needed.

According to the experts cited, such systems can deliver up to 15% savings on annual heating costs, while maintaining a comfortable indoor environment.

The financial impact, however, is not as simple as assuming higher settings always mean sharply higher bills. While the rule of thumb remains that each additional degree can increase heating demand by around 7%, specialists say more appropriate temperatures may reduce expensive workarounds - such as relying on portable heaters or over-ventilating rooms because heat is unevenly distributed.