When does the electric backup heater switch on?
The backup heater helps when the heat pump alone is not enough. Its output is not compressor output.
- Output and electricity use
An electric heater turns each kilowatt-hour of electricity into one kilowatt-hour of heat. With the heat pump it gives more heat but also uses more electricity, so the combined output tells you nothing about how economical the heat pump is. Our calculator recommends a heat pump that copes on its own down to −10 °C and gets no more than 5% of the year's heat from the backup heater.
- When it switches on
The system settings decide it. Check that the house's electrical connection and protection can handle the heater's load. The temperature at which the heater starts helping (the bivalent point) and the priorities are set in the design.
dzese.lv · 25 October 2026. This is general guidance. Where it differs from the chosen model manual or the project calculation, follow those.
