Why does my house feel cold even with the heating on?
Radiator balance, draughts, humidity and cold surfaces — the reasons a warm thermostat reading still feels cold.
- Difficulty
- beginner
- Time
- 45 min
- Read
- 3 min
Short answer
Air temperature is only part of how warm a room feels. Cold surfaces, moving air and damp all make a room at 21°C feel several degrees colder, and all three are more fixable than the heating.
If the thermostat says 21°C and you are cold, the thermostat is not lying — it measures air temperature, and comfort depends on radiant heat from surfaces, air movement and humidity as much as on air temperature.
Step by step
- Check the radiators are heating evenly.Feel each one top and bottom. Cold at the top means air — bleed it. Cold at the bottom means sludge. Radiators near the boiler getting hot while distant ones stay cool means the system needs balancing.
- Find the draughts.Moving air removes heat from skin directly. A room at 21°C with a draught feels markedly colder. Check doors, windows, letterbox, floorboards and unused chimneys.
- Check where the thermostat is.In a hallway, near a draught, above a radiator or in direct sun, it reads the wrong temperature and shuts the heating off too early. This is a common and invisible cause.
- Deal with cold surfaces.A cold external wall or a large window radiates heat away from you regardless of air temperature. Curtains closed at dusk, and furniture arranged away from cold walls, both make a real difference.
- Check the humidity.Damp air feels colder and carries heat away faster. Above about 60% humidity a warm room still feels chilly. Ventilation and reducing moisture help more than more heat.
- Check the radiators are not obstructed.A sofa in front, a shelf above, or long curtains over one all stop the convection the radiator depends on. Nothing should sit against the front.
- Check the flow temperature and the timer.A boiler flow temperature set low takes much longer to warm a room. And heating that comes on an hour before you need it never quite catches up in a cold house.
- Then look at insulation.If the heat goes in and straight out, everything else is a workaround. Loft insulation and draught-proofing are the underlying fix.
Tips
- Balancing radiators costs nothing and is the most commonly skipped heating job. If the far end of the house is always cold, this is usually why.
- Thermostatic radiator valves let you heat the rooms you use and turn down the ones you do not. Setting them all to maximum defeats the point.
- A cheap hygrometer and a thermometer in the actual room you sit in tell you more than the boiler's display does.
If it doesn't work
Some radiators hot, others cold
Cause: System needs balancing — Fix: Balance the radiators — throttle the ones nearest the boiler so flow reaches the far ones.
Radiator cold at the top
Cause: Air in the system — Fix: Bleed it, then top the boiler pressure back up.
Thermostat says warm, room feels cold
Cause: Thermostat badly positioned, or cold surfaces and draughts — Fix: Check where the thermostat is, close curtains at dusk, and deal with draughts.
Whole house slow to warm
Cause: Low boiler flow temperature, or poor insulation — Fix: Check the flow temperature setting; then insulation and draught-proofing.
Questions people ask
Why does my house feel cold at 21 degrees?
Air temperature is only part of comfort. Cold wall and window surfaces, moving air and high humidity all make a room feel several degrees colder than the thermostat reads.
Should I leave the heating on low all day?
For most homes it is cheaper to heat only when needed, though a very poorly insulated house that never warms up can be an exception. Insulation changes this answer more than the schedule does.