Government considers increasing the permitted size of heat pumps

Larger heat pumps may be allowed if UK Government proposals to amend the permitted development right requirement for ground and air source heat pumps are given the green light.

Officials have launched a consultation over whether the allowed volume of ground and air source heat pumps should be raised, as well as changes to where the renewable tech can be placed.

The move follows a recent heat pump DEFRA review, which found that noises generated by the technology found that residents who lived near a heat pump reported few complaints.

 Consultation aims to allow larger, quieter heat pumps 

The government consultation into heat pumps has found that larger heat pumps have the potential to be quieter, as well as being far more energy-efficient.

The official heat pump DEFRA review (Department for Environment, Food and Rural Affairs) into noise problems from heat pumps recommended removing the government's own Microgeneration Certification Scheme (MCS) guidelines for air source heat pumps to be at least one metre away from neighbouring properties.

A study was conducted on a small sample (139) of residents who lived near a heat pump and were asked about the noise from the heat pumps and it was found there were "a low number of complaints" associated with heat pump noise.

It was found that "in quieter areas, noise from ASHPs has the potential to cause relatively more adverse effects" but in areas of higher sound levels "installations may be unduly denied despite higher existing sound levels justifying a higher noise level". It was concluded that the one-metre requirement was "not necessary".

The consultation document states: "The review noted that the existing limitation requiring that an air source heat pump must be installed at least one metre away from the property was a blunt proxy for noise and that, from a noise control perspective, is not necessary as long as there is an upper limit on the noise at the nearby receptor.

"To facilitate innovation in noise reduction, we are considering whether to increase the current volume or size limitation and are interested in your views on a suitable size threshold."

Aims to allow cascade systems with two air source heat pumps in the curtilage of houses 

Permitted development rights for heat pumps could be extended to allow homeowners to have two air source heat pumps instead of one.

Ground and air source heat pump installation is currently limited to one per home without needing planning permission but the government consultation is currently seeking to change this.

The consultation document states: "We are seeking views on whether this limitation could be amended. For example, where the dwellinghouse is detached, it may be appropriate to allow for up to two air source heat pumps to be permitted, to allow for cascade systems.

"We are proposing to allow two air source heat pumps in the curtilage of detached dwellinghouses."

A cascade heat pump system is one that connects more than one heat pump together to meet a home's heating and hot water needs.

Consultation will remove 'arbitrary' planning rules

Bean Beanland, the founding member of the Heat Pump Federation (HPF), commented on the proposed changes claiming they were removing "arbitrary" planning rules surrounding heat pumps.

He stated: "At the moment the stipulation in order to get permitted development says the size of a heat pump has to be less than one-sixth of a cubic metre. That is entirely arbitrary. Nobody can explain where that number came from or what the rationale for it was.

"You could potentially increase the noise insinuation in the device by making the machine a little bit bigger. But you can reduce the fan speed to further reduce the sound and machines are currently getting quieter.

"The 1-metre distance from the boundary was again arbitrary as there was no real science behind it. It could be argued that that has made the problem of noise worse because if the unit is right up against the fence for the sound to go up over the fence the angle for which the noise must go over the fence is more difficult so there was a fundamental lack of understanding of mathematics so having them closer to the boundary is a good thing."

On the increased number of heat pumps he said: “Bigger properties potentially will need more fire power from a heat pump than is provided from a single box. All this is doing is allowing larger homes and leakier homes opportunities to deploy heat pumps under permitted development in a way that is not opening the floodgates to massive abuse and hideous visual impacts. The word cascade is a misnomer as it is unlikely these devices will be deployed in a cascade and will more likely work in parallel to each other.” 

Bean Beanland

Bean, an experienced professional with a background in energy and carbon mitigation, is a founding member of the Heat Pump Federation (HPF). With expertise in technology selection, procurement, and installation, he has overseen numerous heat pump systems for various buildings, including Listed and period buildings, schools, rural estates, and commercial buildings. Active in supporting the development of heat pump technology and government policy, Bean also leads lobbying efforts for the HPF and contributes to membership growth.