Heat Pump Constant vs Setback Heating
Running your heat pump continuously at a low flow temperature can actually cost less than running it for shorter periods at a higher temperature. The COP gains from lower flow temperatures offset the longer running time — a fundamentally different approach from gas boiler schedules.
How you schedule your heat pump directly affects running costs. Connects to flow temperature optimisation and control settings. Pillar: radiators and heat pumps.
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Why Heat Pumps Are Different From Boilers
A gas boiler is either on or off — turning it off saves gas. A heat pump modulates its output with an inverter compressor. Running gently at 35°C for 16 hours may use less electricity than running hard at 50°C for 8 hours to recover from a deep temperature setback.
The Optimal Approach
Use weather compensation with a small night setback (2-3°C). Let the heat pump run for long periods at the lowest effective flow temperature. Avoid large temperature drops that force recovery at higher flow temperatures.
Using Setback Correctly
- 2-3°C night setback: Sensible — minimal recovery energy needed
- 5°C+ setback: May cost more in recovery than it saves overnight
- Complete off overnight: Usually inefficient — high flow temperature needed to recover
With solar panels, schedule any boost heating for daylight hours when solar generation offsets electricity cost.
Frequently Asked Questions
Should I run my heat pump 24/7?
Not necessarily 24/7, but long running periods at low output. A small 2-3°C setback is fine.
Does running constantly cost more?
Often not. Higher COP at lower temperatures offsets longer running time.
Heat pump scheduling differs fundamentally from boiler operation. Connects to flow temperature, radiator sizing, and running costs. Solar panels enable smart scheduling around peak generation.