When Is the Best Time to Install a Heat Pump in the UK?

The timing of your heat pump installation affects waiting times, installation quality, and your ability to test the system before you rely on it for winter heating. Here is what the data shows about when to plan.

Spring (March-May) is the best time to install. Installers are less busy than in autumn and winter, meaning shorter waiting times (typically 4-8 weeks vs 8-16 weeks in November), more choice of installer, and more competitive quotes. Crucially, you can test the system fully during the mild spring weather before the first winter test.

Summer (June-August) is also good for installation, though some installers take holidays in August. The main advantage is testing the hot water and cooling functions (if your system has active cooling) before winter. The main disadvantage is that you won't get a realistic test of winter heating performance until October or November.

Autumn (September-October) sees a significant surge in demand as homeowners realise their old boiler is struggling and want to be sorted before winter. Waiting times extend sharply - 10-16 weeks is common in October, meaning a November booking may not be installed until January or February. If you are planning an autumn installation, contact installers in August.

Winter (November-February) installations are possible but not ideal. Installers are at peak demand, outdoor unit installation is more disruptive in cold weather, and there is pressure to commission quickly. That said, many excellent installations happen in winter - it is just worth knowing the constraints.

One practical tip: if you get quotes in spring or summer, many installers will hold a slot for you 2-3 months in advance. This gives you the benefit of careful planning while securing good autumn availability. The BUS grant voucher, once issued, is valid for 12 months - so you have flexibility on timing once the process has started.