Heat Pump Noise Levels

Modern air source heat pumps (ASHPs) are designed to run quietly and efficiently, but like any outdoor mechanical equipment, they do produce some sound. Understanding heat pump noise levels — and how UK regulations control them — is important for correct installation, neighbour considerations, and long-term satisfaction.

This UK-focused guide explains how loud heat pumps actually are, how noise is measured, how placement affects sound levels, and how to ensure compliance with UK planning rules.

Typical Noise Levels of Modern Air Source Heat Pumps

Most air source heat pumps operate within:

📌 40–60 dB, measured 1 metre from the outdoor unit.

This range is similar to other everyday sounds:

Sound Source	Approx. dB Level
Whisper	30 dB
Quiet conversation	40–50 dB
Modern heat pump (avg.)	40–55 dB
Electric shower	70 dB
Vacuum cleaner	70–80 dB

Even at the higher end of their operating range, heat pumps remain on the quieter side of household noise. Many premium models operate at 35–45 dB, making them barely noticeable from a short distance away.

Why Heat Pumps Are Quiet in Real-World UK Use

Heat pump technology has advanced significantly in recent years. Features that contribute to quieter operation include:

• Variable-speed (inverter) compressors

  Older systems switched on and off at full power, causing noticeable noise. Modern ASHPs modulate smoothly and spend most of their time at low output levels.

• Aerodynamically optimised fans

  Fan blade shape and motor control reduce turbulence, the main source of fan noise.

• Vibration-reduction engineering

  Rubber isolation mounts, smoother motor balancing, and better chassis design help prevent humming or rattling.

  Sound-insulated casings

Acoustic panels and weatherproof shells keep internal noise contained.

Real-world experience:

Most homeowners describe the noise as similar to a quiet fridge humming, especially once the unit is a few metres away or partially shielded by landscaping.

What Causes Noise from a Heat Pump?

While heat pumps are quiet, slight operational sounds are normal. The main sources include:

1. The Fan

Draws air across the heat exchanger. Usually the quietest component, especially at lower speeds.

2. The Compressor

Generates a soft hum when running. Modern rotary and scroll compressors are highly refined and quiet.

3. Airflow Obstruction

If the unit is placed too close to walls, fences, or corners, airflow becomes turbulent, increasing noise.

4. Defrost Cycles (winter)

In the UK’s damp, cold climate, heat pumps periodically defrost to maintain efficiency. During this stage:

• Fan speed may increase briefly

• A soft whoosh or gurgle may be heard

• Noise remains temporary and within expected levels.

How Noise Levels Change Throughout the Day

Heat pumps do not remain at a constant volume. Their sound output reflects the heating demand:

Early morning & evening

When the system replenishes heat or hot water, it may run slightly louder.

Daytime

Often extremely quiet, low output means the compressor and fan operate slowly.

Night-time

Many units reduce noise automatically:

• “Quiet mode” limits fan speed

• Some models shift running cycles to earlier hours

• UK planning rules incentivise night-time noise reduction

This ensures compliance even in densely populated areas.

UK Planning Rules and Noise Regulations

Heat pump installations in England and Wales generally fall under Permitted Development, meaning no planning permission is needed if they meet the following standards.

MCS 020 Noise Assessment

Every MCS-certified installer must conduct an acoustic assessment ensuring:

• ✔Noise does not exceed 42 dB at the nearest neighbour’s window

• The outdoor unit is at least 1 metre from property boundaries

• Sound reflections and amplifying surfaces are minimised

If these criteria are met, the installation meets national regulations.

When planning permission may be required

• Listed buildings

• Conservation areas, national parks, Areas of Outstanding Natural Beauty

• Installing more than one outdoor unit

• Certain flats or commercial setups

Scotland and Northern Ireland follow similar but slightly adapted rules.

Best Locations to Minimise Noise

Where the heat pump is placed has a big impact on perceived loudness.

Recommended placement:

• Ground-level installation in the garden

• On a solid concrete pad with anti-vibration feet

• Away from bedroom windows

• Avoiding narrow passages or corners that cause echo

• Ensuring free airflow on all sides

• Positioned so it is not directly facing a neighbour’s home

  
  

Good placement alone can reduce perceived noise by up to 50%.

How Installers Reduce Noise in UK Installations

Professional, MCS-certified installers apply a variety of techniques:

•  Anti-vibration mounts

  Stop mechanical vibrations travelling into walls or the ground.

•  Flexible pipework

  Prevents resonance noises where pipes enter the home.

• Sound-optimised placement

  Installers choose positions to minimise reflective surfaces and neighbour impact.

• Correct airflow clearances

  Ensures efficient and quiet fan operation.

• Night-mode options

Many systems include programmable low-noise settings, essential for urban or suburban environments.

Do Heat Pumps Disturb Neighbours?

Noise complaints about modern heat pumps are rare when systems are installed correctly.

Why?

• They run quietly for the majority of the time

• Planning rules safeguard neighbouring properties

• Units are often placed behind houses, away from streets and boundaries

• They are quieter than alternatives

• Oil boilers, generators, and older air-con units are all significantly noisier.

Studies show that with proper siting, a heat pump becomes almost inaudible at a few metres away, particularly in outdoor British ambient noise (wind, birds, traffic, etc.).

Can You Make a Heat Pump Even Quieter?

Yes, several enhancements can reduce noise further:

Acoustic fencing or barriers

Useful if the pump must be near a boundary. Must allow adequate airflow to avoid overheating.

Rubber isolation feet

Prevent vibration transfer into decking, patios, or brackets.

Choose an ultra-low-noise model

Some advanced systems achieve 35–40 dB — quieter than a modern fridge.

Regular cleaning

Removing leaves, dirt, or debris improves airflow and reduces turbulence noise.

These steps are optional but beneficial in sensitive locations.

Air source heat pumps are one of the quietest heating technologies available for UK homes. With:

• Typical sound levels of 40–60 dB (often less in practice)

• Strict UK planning rules that cap noise at neighbours’ properties

• Modern low-noise engineering and smart controls

• Professional installation ensuring optimal positioning

A heat pump should operate quietly and blend seamlessly into everyday life. Most homeowners quickly forget it’s even running. If you want to swich to an air source heat pump then contact our team at Newpower today.