A realistic look at performance when temperatures drop.
One of the most common questions about heat pumps is how well they work when it’s cold outside. Since they extract heat from the air, it’s natural to wonder what happens when there’s less heat available.
The short answer is: they still work, but efficiency drops as temperatures fall. Understanding what to expect helps set realistic expectations.
Heat pumps don’t generate heat like a gas boiler — they move it from outside to inside your home. Even when it’s cold outside, there is still some heat energy in the air. The heat pump extracts this and concentrates it to warm your home.
However, the colder it gets, the harder the heat pump has to work. This means:
In most parts of Devon and Cornwall, winter temperatures rarely stay below freezing for long periods. This means heat pumps generally perform well for the majority of the heating season.
During a typical cold spell (around 0°C to -5°C), you can expect:
Very cold snaps (below -5°C) are uncommon in this region, but when they do occur, running costs will be higher than average.
Heat pumps work best when left on at a steady temperature rather than being turned off completely when it’s cold.
Better insulation reduces the amount of heat the system needs to produce, which helps performance in cold weather.
Make sure the weather compensation curve is set correctly so the system automatically adjusts as outdoor temperatures drop.
Make sure the area around the outdoor unit is kept clear of snow, leaves, or debris so it can work efficiently.
Use our Heat Pump Estimator to get a realistic indication based on your property.