What Temperature Should Your Thermostat Be Set To?

18–21°C is the sweet spot for most Northampton homes. Here's how to choose the right setting room-by-room.

By Jordan Lamb · Gas Safe Engineer · Northampton

The science: 18–21°C is the sweet spot

The World Health Organisation recommends a minimum of 18°C in occupied rooms, and Energy Saving Trust research shows that 18–21°C is comfortable for most UK adults. Every 1°C you turn the thermostat down saves around 10% on your annual heating bill — for a typical Northampton home, that's £100–£140 a year per degree.

Living areas: 20–21°C

Lounges and dining rooms should sit around 20–21°C in winter. Babies, elderly residents and anyone with circulation issues benefit from 21°C; healthy adults are perfectly comfortable at 19–20°C with a jumper. Pair this with TRVs on every radiator so you only heat the rooms you're using.

Bedrooms: 16–18°C

Sleep science is clear: 16–18°C is the ideal sleeping temperature. Bedrooms also benefit from being slightly cooler to reduce overnight condensation on cold external walls — a major cause of black mould around windows in older Northampton terraces.

Empty homes & holidays: never below 12°C

If you're away in winter, set the thermostat to 12°C as a frost-protection minimum. This costs pennies a day and prevents pipes freezing — which is the single most common claim on home insurance after burst pipes.

Smart controls — worth fitting?

A Glow-worm Climapro 2, Hive, Nest or Tado fitted to your existing system pays back within 2–3 years through smarter scheduling, geofencing (turning down when you leave the house) and per-room control. I fit and commission smart controls across Northampton — typical job is £180–£280 fitted.

Frequently asked

Is it cheaper to leave heating on low all day?

No — for most homes, heating only when you need it (with a good schedule) is significantly cheaper than constant low heat.

What boiler flow temperature should I run?

60°C flow temperature on a combi gives the best efficiency for most Northampton homes — counterintuitively, lower than the factory default of 75–80°C.

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