Why is my heat pump noisier than usual?

Q: Why is my heat pump noisier than usual?

It works harder, and sounds louder, on the first cold days of the year. Rushing or ticking in the pipes is often air, fixed by bleeding the radiators. Grinding, squealing or loud gurgling needs a professional.

Updated 29 September 2026

Short answer: it works harder, and sounds louder, on the first cold days of the year. Rushing or ticking in the pipes is often air, fixed by bleeding the radiators. Grinding, squealing or loud gurgling needs a professional.

A heat pump's circulating pump runs a little faster than a boiler's, so some sound in the pipes is normal. If it has got louder, air in the system is the usual cause. Bleeding the radiators — letting the trapped air out through the small valve at the top — means the heat pump won't have to work so hard.

Get used to how yours normally sounds. A new grinding, squealing or loud gurgling noise from the outdoor unit usually means something needs fixing, so don't ignore it.

If none of this helps, Octopus has a Cosy support page with its aftercare contacts. Snugdays is independent and can't fix the heat pump itself.