How Loud is a Heat Pump? Noise Levels Explained

The Vaillant aroTHERM Plus produces 48 dB(A) at 3 metres at full load. For context:

• A whisper: 30 dB(A) • A refrigerator humming: 40 dB(A) • Vaillant aroTHERM Plus: 48 dB(A) at 3m • Normal conversation: 60 dB(A) • A washing machine: 70 dB(A)

At the nearest neighbour’s window (typically 5–10 metres away), the sound level drops further to around 35–42 dB(A) — quieter than a fridge.

Most of the time, your heat pump will not be running at full load. At partial load, noise levels drop significantly — often below 40 dB(A) at 3 metres.

As MCS-certified installers, we carry out a formal noise assessment for every installation (using the MCS 020 planning standard). This calculates the sound level at the nearest noise-sensitive point (typically a neighbour’s window or bedroom).

The permitted development limit requires the noise level not to exceed 42 dB(A) at 1 metre from a neighbour’s habitable room. We model this during the design phase and position the unit accordingly. If a particular location does not meet the noise criteria, we find an alternative position before any work begins.

Good placement makes a big difference:

• Distance from boundaries — Every doubling of distance reduces noise by about 6 dB(A). • Avoid reflective surfaces — Placing a unit between two walls can amplify noise. Open positions are quieter. • Soft ground — A unit on grass or gravel is quieter than one on concrete, which can reflect sound. • Anti-vibration mounts — We always install rubber anti-vibration feet to prevent structure-borne noise. • Acoustic barriers — In tight spaces, a simple fence or planted hedge can reduce perceived noise significantly.