UK homeowners installing air conditioning units this summer may be unknowingly breaching planning rules, as such installations do not fall under permitted development rights, according to an expert.
Planning Permission Required for Air Con Units
John Van-Eker, principal planning consultant with Planning Portal's Planning Guidance Service, a joint venture between the Ministry of Housing, Communities and Local Government and TerraQuest, warned that widespread misinformation online has led many to believe air con units can be installed without permission.
“Because of widespread misinformation online, homeowners may not realise that they actually need to submit an application for planning permission to install an air con unit – potentially landing them in hot water if they didn’t receive approval,” Van-Eker said.
While certain home improvements are allowed under permitted development rights, air conditioning units are explicitly excluded. Homeowners must apply to their local authority and wait up to eight weeks for approval, which can feel lengthy during a heatwave.
Consequences of Installing Without Permission
Installing a permanent air con unit without authorisation can lead to significant repercussions. Homeowners may be forced to submit a retrospective planning application. If rejected, the council can issue an enforcement notice requiring removal. Ignoring such a notice is illegal and could result in prosecution.
Additionally, selling a property with an unauthorised air con unit can complicate transactions. Sellers must demonstrate that necessary approvals were secured; otherwise, they may need to submit a retrospective application or remove the unit entirely.
Replacement and Upgrades
Van-Eker clarified that replacing an existing air con unit with a like-for-like model does not require planning permission. However, upgrading to a larger or more powerful unit necessitates a new application via the Planning Portal website.
“If your home already has a permanent aircon unit installed and you need to replace it, if you’ve chosen a like-for-like model then you don’t need to apply. However, if you’re looking to upgrade to a larger, more powerful unit, you will need to submit an application,” he said.
Alternative Cooling Solutions
Recent changes to permitted development rights in May 2025 have made it easier to install heat pumps, which can both heat and cool homes year-round. Van-Eker suggested this as a viable alternative for homeowners seeking to stay comfortable without the planning hurdles associated with air conditioning.
“Misinformation online can easily mislead homeowners into thinking a project is covered by permitted development, when it actually requires an application for planning permission,” Van-Eker added. He advised consulting an expert or using a verified planning provider like Planning Portal's Planning Guidance Service to proceed with confidence.
“Even though UK summers are getting warmer each year, making sure that you have the necessary permissions to install an aircon unit is vital to prevent you from being scorched by the consequences,” he concluded.
