Before the first hot week, take 10 minutes to clean the filters, clear around the outdoor unit, test the cooling, check the drain and set a sensible temperature. If it still isn’t cooling properly, or it smells musty or leaks, book a service before the summer rush.
In this article6 sections
Most heat pumps spend winter on heat and then get switched to cool on the first hot day of summer. Problems that built up over winter show up then, usually just as everyone else is calling for a service. These five checks take about 10 minutes and catch most of them early.
1. Clean the filters
Switch the heat pump off, lift the front cover and slide out the filters. Vacuum them or rinse them in lukewarm water, let them dry fully, and slide them back in. Clogged filters are the most common reason a heat pump cools poorly, smells musty or costs more to run.
2. Clear around the outdoor unit
Pull back plants, leaves and anything stored against the outdoor unit so air can flow freely around it. Leave about half a metre clear on all sides and don’t cover it. A blocked outdoor unit has to work much harder on a hot day.
3. Test the cooling
Switch to cool, set it to around 23°C and give it 10 to 15 minutes. The air from the indoor unit should feel noticeably cooler than the room, and the outdoor fan should be running. If it’s blowing room-temperature air, it needs a look.
4. Check the drain and for leaks
In cooling mode a heat pump takes water out of the air, and that water drains away through a small pipe. After it has run for a while, check there’s no water dripping from the indoor unit and that the drain outside is clear and running.
5. Set it up for summer
Check the remote batteries, the clock and any timers. Around 23 to 25°C is comfortable and keeps running costs down, and the dry mode is useful on muggy days. Closing curtains on sunny windows helps too. See heat pump running costs.
When to book a service
Book a service if the heat pump still cools poorly after cleaning the filters, smells musty, drips water, makes new rattling or humming noises, or hasn’t been serviced in the last year. A service cleans the coils and drain and checks the system is working as it should. See heat pump servicing or, if it isn’t working at all, heat pump repairs.
Frequently asked questions
What temperature should I set my heat pump to in summer?
Around 23 to 25°C is comfortable for most people and keeps running costs down. Setting it much lower makes it work harder without cooling the room faster.
Why is my heat pump not cooling?
The most common reasons are dirty filters, a blocked outdoor unit or the wrong mode. If it still isn’t cooling after the checks in this guide, book a service.
How often should I clean the filters?
Every few weeks while you’re using it a lot, and always before summer and winter.
Is it normal for water to drip outside in cooling mode?
Yes. In cooling mode a heat pump removes moisture from the air, and that water drains outside. Water dripping inside, from the indoor unit, is not normal.
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Ready for a comfortable home all year?
Not cooling like it should? Book a heat pump service before the summer rush.