Why is my heat pump making that noise?

Some noises are completely normal. Others are your heat pump asking for help.

A guide to observations, not a diagnosis by sound.

What does yours sound like?

Pick the closest description.

• Hum — A steady hum can accompany normal operation. A new, much louder or changing hum deserves attention.
• Whoosh — Air moving through the fan can sound like a whoosh. Note whether it changes during a short operating cycle.
• Click — A brief click can accompany switching. Repeated clicking, an error code or lost heating needs investigation.
• Rattle — A new rattle could involve vibration or a loose part. Observe from outside; do not remove covers.
• Buzz — Buzzing can have several causes. A recording and the timing may help an engineer; sound alone is not a diagnosis.
• Grinding — A new grinding sound warrants prompt professional assessment. Avoid touching the fan or opening the casing.

Listen for the pattern.

Notice when the sound begins, how long it lasts, and whether the rooms and hot water still feel as expected. A new sound is more useful to describe than a sound in isolation.

Weather changes things.

In cold weather, a heat pump can run a defrost cycle. Daikin’s homeowner guidance describes temporary vapour and melting ice during this process.

Keep your distance.

Listen from outside the unit. Don’t remove guards or try to stop a fan. If there is smoke, a burning smell or another immediate danger, stop using the system if safe and seek urgent help.

A useful note for your engineer.

• The manufacturer and full model number.
• The sound, its timing and any displayed code.
• Whether heating or hot water has changed.
• A short recording, taken from a safe distance.

The sound descriptions are general observation prompts, not manufacturer fault classifications.