Do Heat Pumps Generate Noise?

‘How noisy are heat pumps’ is a question regularly put to our team when discussing an installation with clients. It’s a valid question – no matter how energy efficient or environmentally friendly the heat pump, if it’s going to cause a nuisance then something has to be done to make it acceptable.

The truth is, the noise generated by a heat pump can vary significantly. Everything from the design of the heat pump, the components used, the installation and the demand profile all affect noise. Of course a heat pump only reaches the loudest levels during peak demand and so variations over time must also be considered.

Overall, though, a high quality, modern heat pump from a reputable manufacturer on a well designed scheme will not produce noise that becomes a nuisance.

How Noisy Are Air Source Heat Pumps?

Air source heat pumps have four main working components, as we discuss in our video about how heat pumps work. There is a compressor, a condenser, an expansion valve and an evaporator.

The components that make the most noise are the fans and the compressor.

The fan’s noise output depends on a few things: the type of fan, the airflow, and the speed. Air generates noise when passing through the fan, and the amount of noise generated depends on the quality of the design and the velocity of the blades and air. When the heat pump is working harder, the air velocity will need to be higher and therefore the noise will be higher.

However, again it’s a question of design and calibration. A modern, well-built heat pump should not run into these issues often enough for it to be a problem. At Clade all our compressor stations come in acoustic housing which reduces compressor noise to a whisper, leaving the fans for which Clade offer 3 types of noise abatement; fan attenuators, increased numbers of fans to reduce the speed, and noise shielding which encloses the whole heat pump. All three are effective but have different characteristics that should be considered by the design team.

How noisy are ground source heat pumps?

Ground source heat pumps make less noise because they don’t need fans and so it’s only the compressors that make noise.

However, there are higher installation costs to consider with ground source heat pumps. If you’d like to know more about the pros and cons, read our blog comparing air source and ground source heat pumps.

Noise Regulations For Heat Pumps

When a heat pump is installed, the installer has to consider noise effects. .

Regulations state that if a heat pump produces 45db or more of noise it can’t be within 1m of a neighbouring residential property. If the heat pump produces 42db or more of noise for your neighbours, planning permission is required for installation.

BS 8233 provides guidance on acceptable internal ambient noise levels in dwellings and
BS4142 is the relevant standard for calculating noise from commercial sized heat pumps.

Here are our tips to reduce the impact on noise before mitigation measures are considered:

-Ensure the heat pump unit has acoustic housings for compressors and inverters etc.
-Ensure the heat pump is installed as far as is practically possible away from neighbouring properties.
-Ensure the heat pump is mounted on vibration absorbing mounts or pads
-Use a thermal store to shorten and move peak generation times to a more acceptable time of day.
-Specify low noise at the outset as it is easier to deal with in the factory than on site.

With all that taken into account, no one should ever be bothered by the noise your heat pump makes, whether it’s air source or ground source.

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