Heater turns on but does not reach temperature
Quick checks (heat-up time, door seal, vent position, stone air gaps), then deeper causes if it runs 45+ minutes without reaching set temperature.
Check first
- How long has it been running? Heat-up takes 30 minutes from a cold start. In extreme cold (below -20°F / -29°C), expect 35 to 40 minutes.
- Is the door fully closed and the window seal tight?
- Are the airflow vents in their correct positions (not fully open during heat-up)?
- Are the stones loaded properly with air gaps for circulation?
If the heater runs for 45 minutes or more without reaching the set temperature, possible causes:
- Voltage drop on the circuit (have your electrician verify)
- Heating element failure on the heater (rare; covered under Harvia warranty, see Section 13.4)
- Controller calibration drift (the cabin may actually be at temperature even though the display shows lower)
- Excessive air leakage from the cabin (uncommon; usually a sign of an installation issue)
Contact our team with the model, the controller setting, the actual temperature you're seeing, and the heat-up time.