One of the most common questions we’re asked about heat pumps is simple:
“Are they noisy?”
It’s a fair concern. Nobody wants to spend money on a new heating system only to feel like they’ve installed a constant background hum in their garden or upset the neighbours.
The good news is this: modern heat pumps are far quieter than most people expect. In this post, we’ll explain how loud they actually are, what the rules are in the UK, and what really makes the difference when it comes to noise.
How loud is a heat pump?
Most modern air source heat pumps produce around 40–50 decibels (dB) during normal operation. Even when working harder, such as during very cold weather or a defrost cycle, they typically peak at 55–60 dB.
To put that into context:
- 30 dB – a quiet library
- 40 dB – a quiet room or fridge humming
- 50 dB – light rainfall
- 60 dB – normal conversation
- 70 dB – vacuum cleaner
In real terms, a properly installed heat pump is usually closer to background noise than anything intrusive.
UK noise regulations explained
In the UK, heat pumps are covered by strict planning and noise rules.
Most domestic installations fall under Permitted Development, but they must comply with MCS 020 noise standards. The key requirement is that the heat pump must not exceed 42 dB at the nearest neighbour’s boundary.
This limit is assessed at the quietest time of night, when background noise levels are lowest. If a heat pump meets this requirement at night, it will be even less noticeable during the day.
These rules exist specifically to protect neighbours and ensure heat pumps don’t become a nuisance.
Why do some people think heat pumps are noisy?
When noise complaints do happen, it’s rarely because of the heat pump itself. It’s almost always down to poor design or installation.
Common causes include:
- Poor placement, such as being too close to bedroom windows
- Installing units in corners or tight spaces that reflect sound
- Lack of anti-vibration mounts
- Systems that are undersized and forced to run flat-out
- Older or low-quality units
A well-designed system should run smoothly and steadily, not constantly ramping up and down.