Heating curve
The heating curve determines how warm the heating water should be at a given outdoor temperature. Correctly adjusted, it saves electricity while maintaining the same level of comfort.
- Flat curve, typical for underfloor or wall heating: low flow temperature even in frosty conditions.
- Steep curve, typical for radiators: when it is cold, a significantly higher flow temperature is required.
- The flatter and lower the curve, the more efficiently the heat pump runs.
A heat pump usually operates in a weather-compensated manner: a sensor measures the outdoor temperature, and the control system uses this to select the appropriate flow temperature. The heating curve is this mapping. It has two adjustment parameters:
- Base point (level): shifts the entire curve up or down.
- Slope (steepness): determines how much the flow temperature increases when it gets colder outside.
Why this is important for your house
If the curve is set too high, the heat pump heats with unnecessarily warm water. This reduces efficiency. klimaaktiv writes that simply adjusting the heating curve can lower the flow temperature by a few degrees and permanently save operating costs.
How to recognise a heating curve that is too high
The klimaaktiv guide to hydraulic balancing suggests a simple test: on a very cold day, turn all radiators fully open. If it gets too warm, the curve is too high. Another sign: the entire flat can be heated using only some of the radiators.
Rules of thumb for readjustment
- Always too cold: raise the base point. Always too warm: lower the base point.
- Too cold only on very cold days: increase the slope slightly.
- Too warm during the transitional period, but fine in winter: lower the level, increase the slope.
Always make changes in small steps and wait a few hours. Have the setting explained to you during handover, see after installation.
Related terms
Flow temperatureHydraulic balancingSurface heating (underfloor and wall heating)Seasonal performance factor (SPF)
Sources