Five things to do before the first heatwave hits

Every year the phones light up on the first 28°C day. Here is how to make sure you are not one of those calls.

1. Pull and wash your filters. Ten minutes with warm water and a soft brush restores airflow and can cut running costs noticeably. Let them dry fully before refitting.

2. Clear the outdoor unit. Give it 30cm of free space on all sides and remove leaves, cobwebs and anything stacked against it over winter.

3. Run it in cooling for twenty minutes. Better to discover a fault in March than during a heatwave when every engineer in Surrey is booked out.

4. Check the condensate drain. A slow drip or a musty smell usually means a partially blocked drain that will overflow at the worst possible moment.

5. Book your annual service. It protects the manufacturer warranty, keeps efficiency up and catches worn parts before they strand you.