Symptoms
- One area of the house is always too hot or cold
- System seems to run based on a temperature that doesn't match most of the house
- Thermostat is near a window, vent, kitchen, or exterior door
Likely causes
- CommonDirect sunlight hitting the thermostatSun exposure heats the sensor directly, making the thermostat think the room is warmer than it is.
- CommonPlacement near a supply vent or returnDirect airflow gives a reading that reflects the vent, not the room.
- PossibleLocation near a heat-generating appliance or exterior doorKitchens, entryways, and rooms with electronics run warmer or draftier than average.
- PossiblePlacement on an exterior wallExterior walls can run cooler in winter and warmer in summer than interior walls.
What to do
- Note the thermostat's current location and any nearby sun, vents, doors, or appliances.
- Compare its reading to a thermometer placed in a central, commonly used room away from those influences.
- If a real discrepancy exists, consider relocating the thermostat to an interior wall in a central hallway or living area, about 5 feet off the floor.
- If relocation isn't practical, use the thermostat's calibration offset to compensate, understanding this is a workaround rather than a true fix.
- For smart thermostats with room sensor support, place a remote sensor in a more representative room and prioritize it in the app.
Tools and parts
- Separate room thermometer
- Screwdriver (if relocating)
Remote room temperature sensorSearch: “smart thermostat remote room sensor”
When to call a pro
Call an HVAC technician or electrician if relocating the thermostat means running new wire through walls.
Safety
Use caution
Turn off power at the breaker before disconnecting wiring if relocating the thermostat.