The number of UK homes with air conditioning has doubled in five years, from 2% to 4%, about 500,000 households. Now the net zero clampdown is coming for them.
As reported by The Telegraph, the latest update to Part L of the Building Regulations, the section governing energy efficiency, now treats air conditioning as a regulated energy use. Installers and homeowners must prove the unit meets minimum Seasonal Energy Efficiency Ratio (SEER) standards. If it doesn’t, enforcement officers can demand its removal.
Who qualifies, and who doesn’t
The rules apply to new installations and any replacement of existing units from June 2023 onwards. For existing homes, the trigger is usually a material change of use, selling, extending, or major renovation. If you are simply replacing a broken unit like-for-like, you may escape the net. But the catch is that most older units, those installed before 2021, have SEER ratings well below the new threshold of 4.0. A typical 2018 model might score 2.5. That is a 40% gap, and enforcement is growing.
Local authorities have already issued 47 enforcement notices in England since April 2024, according to documents seen by The Telegraph. The average cost to remove and replace a single split-system AC is £3,200, including disposal fees and new insulation work. For a three-bed semi with two units, that is £6,400, before you even consider alternative cooling.
What it costs a typical 3-bed semi
Ofgem estimates that a typical household using 2,500 kWh annually for cooling, about 10% of total electricity use, pays £375 a year. A non-compliant AC unit that is 50% less efficient could cost an extra £190 annually. Over 10 years, that is £1,900 in wasted energy. But the removal cost is upfront, and most households do not have £3,200 spare.
The Energy Saving Trust recommends passive cooling first: external shading, reflective blinds, and loft insulation that keeps heat out in summer. These measures cost £500–£1,500 combined and can reduce indoor temperatures by 3–4°C without electricity. Yet fewer than 1 in 10 UK homes have any external shading, according to a 2023 survey by the Building Research Establishment.
The ‘but’ pivot, what this misses
But the regulations miss a important reality: UK summers are getting hotter. The Met Office recorded 40.3°C in July 2022. By 2050, the average summer temperature in southern England could rise by 3°C. Air conditioning is not a luxury, it is a health necessity for the elderly and vulnerable. Forcing removal without providing affordable alternatives risks heat-related illness.
The government’s own impact assessment, published in December 2023, acknowledged that the rule could increase heat stress in homes without AC. Yet the Department for Levelling Up, Housing and Communities pressed ahead, arguing that the net carbon saving of 2.3 million tonnes of CO2 by 2050 outweighs the health risk. That trade-off is cold comfort to a household that loses its only cooling system.
Caveat honestly, what the rules actually say
Officials have not confirmed when the full enforcement regime begins. The current guidance is advisory until June 2025, after which local authorities can issue compliance notices. The penalty for non-compliance is a fine of up to £5,000 per unit, plus the cost of reinstatement. But the rules only apply to units that are ‘fixed’, not portable ACs. Portable units, which cost £200–£400, are exempt, though they are typically half as efficient as fixed systems.
What to do and by when
Check the SEER rating of your AC unit now. If it is below 4.0, plan for replacement or removal before June 2025. Contact a certified installer listed on the MCS (Microgeneration Certification Scheme) database, they can quote for a compliant unit that costs £1,500–£3,000 installed. Alternatively, invest in passive cooling: external blinds (£200 per window), loft insulation top-up (£400), and a portable AC as backup (£300). The total is £900, versus £3,200 for removal. Households on standard variable tariffs can check eligibility for the government’s Home Upgrade Grant, which covers some cooling improvements for low-income homes. Applications close on 31 March 2027.
Frequently Asked Questions
Yes, if the unit does not meet the new SEER 4.0 standard and you are required to bring the property up to current Building Regulations as part of the sale. However, enforcement is typically triggered only if the buyer's survey identifies non-compliance. Many sellers choose to replace the unit before listing to avoid delays.
No, the regulation applies to the unit's efficiency rating, not how often you use it. Even if you run it only on the hottest three days of the year, a non-compliant unit that is discovered during a renovation or sale must be removed or replaced. The only exception is portable units, which are not covered by the rules.
