Heat pumps could present a noise problem if rolled out on mass, so the
government is looking at what can be done to fix the issue — with its findings
expected to be released by the end of the summer
The UK government has set a target of 600,000 heat pump installations
per year by 2028 as part of its bid to decarbonise heating.
While there are fewer than 50,000 fitted in British homes every year,
demand is set to skyrocket as eco-conscious consumers demand greener energy
and installers bring prices down.
But the potential noise problem presented by the humming of multiple air
source heat pumps in residential areas has prompted an official government
review by the Department for Environment, Food and Rural Affairs (Defra).
How do heat pumps produce noise?
Heat pumps pump heat from one place to another. They use a compressor
and a circulating structure of liquid or gas refrigerant to extract heat
from outside sources and pump it indoors.
There are two different types – air source heat pumps absorb heat from
the outside air, while ground source heat pumps use pipes buried in the
garden to extract heat from the ground.
The reason air source heat pumps are relatively noisy is the main elements
– compressor, AC condenser, expansion valve, fan, and evaporator – can
all be heard operating when in use, particularly the compressor and the
There is also noise produced by vibrations. The air can produce noise
when passing through the heat exchanger, with a variable intensity depending
on the pressure. This causes buzzing sounds to be emitted and it’s this
constant hum that can disturb homeowners and neighbours, particularly when
there are several heat pumps operating in close proximity.
How much noise do they produce?
To ensure neighbours aren’t disturbed during air source heat pump installation
Permitted Development requires sound levels to not exceed 42 decibels when
measured at a point one metre away from the neighbour’s nearest door or
According to manufacturer Environ Technologies, an air source heat pump
generally produces noise levels of 40-60 decibels from a distance of one
metre away, depending on the model.
However, units get quieter as the technology evolves. For example, the
latest model of Mitsubishi Electric’s latest Ecodan air source heat pump
claims to be quieter than the average gas boiler.
Calls for trials to assess impact of noise pollution
While individual units are quiet, experts fear that multiple heat pumps
in a residential area could cumulatively lead to a noise problem.
The Telegraph reports that issues around noise pollution were reported
by the Department for Environment, Food and Rural Affairs (Defra) and a
review on the issue is being prepared.
Mike Foster, chief executive of utilities lobby group the Energy and Utilities
Alliance, told The Telegraph that heat pumps should undergo a trial before
they are rolled out.
“We are aware of the concerns around noise emitted from heat pumps, he
said. “If the Government really cared about consumers they would order
a large-scale trial, with every home having a heat pump fitted, to test
the cumulative noise levels of mass heat pump installations.”
Meanwhile, Chris Harvey, Heating Specialist from Stelrad, tells Homebuilding
& Renovating “All heating products will make noise, the volume of noise
will depend on how much work the product is doing.
"For heat pumps, the greater the workload, the louder the heat pump will
be. This is due to the speed of the fan that is drawing warm air into the
compressor. But if you stood next to a heat pump, you’d expect the noise
level to be similar to a microwave or a whirring desk-top fan.
"It might be irritating if it was in your bedroom and you wanted peace
and quiet, but the good news is that heat pumps are kept outside, out of
Government orders review into noise from heat pumps
The Department for Energy Security and Net Zero said it expects the review
to be released by summer. It will probe how design enhancements and installation
locations can reduce the volume.
A Defra spokesperson said: “Heat pumps are a proven, scalable option for
decarbonising heat. These are located outside the home and typically have
sound levels similar to a fridge.
“We have seen incredible innovation over the past decade, particularly
in noise reduction, and are reviewing this to ensure planning rules keep
pace with advances in technology.”
How to minimise heat pump noise
Chris Harvey explained that minimising noise pollution from your heat
pump is all about positioning.
"If you are worried about this noise, then the location that you install
them in should be the first thing that you consider. You probably shouldn’t
place a heat pump below any windows, so ensure that proper planning is
conducted before installing and there shouldn’t be an issue," he told Homebuilding
"There are official planning requirements when it comes to air source
heat pumps (which will be noisier than ground source heat pumps), however,
this should not be a problem if planned carefully. They need to be installed
by an expert, and really it all comes down to location and where you are
"It’s understandable that people will be concerned if there is constant
humming in residential areas (if hundreds are placed outside people’s homes).
Research is currently being done regarding the cumulative noise levels
of heat pumps, so perhaps a trial should be undertaken before they are
all rolled out to test the cumulative noise levels of mass heat pump installations.
"Perhaps a better design can reduce the noise volume, as well as how they
are positioned, this is something which the technology and innovations
that we have seen in recent years should be able to help with.”
Taken from an article By Sam Webb