Britain’s residential cooling market is moving out of the margins. New government figures show that approximately three million English homes were reported as becoming uncomfortably hot and difficult to cool in 2024, while policy changes now support air-to-air heat pumps that can provide both heating and cooling.
The shift creates a significant opportunity for HVAC contractors, electricians, façade specialists, retrofit designers and building-performance consultants. But it also exposes a deeper problem: much of the existing housing stock was not designed to control summer solar gain, provide secure night ventilation or accommodate widespread mechanical cooling.
For the construction sector, the question is no longer whether more homes will install cooling. It is whether the market responds with coordinated building upgrades or simply adds equipment to properties whose glazing, ventilation, electrical capacity and fabric performance remain unresolved.
Air conditioning can reduce dangerous indoor temperatures, but it cannot correct the building-performance failures that created the overheating load. Britain’s cooling market will only be resilient if passive measures, electrical design, refrigerant compliance and active cooling are treated as one coordinated retrofit system.
Jump to: By the numbers | What the evidence shows | The Part O gap | Passive cooling first | The new cooling market | Electricity demand | Compliance | Project delivery | Three pathways | LCM analysis | FAQ
By the Numbers: England’s Emerging Cooling Market
| Evidence Point | Latest Position | Construction Reading |
|---|---|---|
| Homes reporting overheating | Approximately 3 million English homes in 2024. | Overheating is already a large existing-stock retrofit issue, not only a future climate projection. |
| Five-year change | Reported overheating rose from 7% of occupied homes in 2019 to 12% in 2024. | Cooling demand is emerging faster than much of the housing stock can be comprehensively upgraded. |
| Air-conditioner use | 7% of overheating households reported switching on an air conditioner. | Adoption remains limited, but the official survey notes that self-reported use does not necessarily confirm ownership of a fixed system. |
| Air-to-air heat-pump grant | £2,500 under the Boiler Upgrade Scheme for eligible installations from 28 April 2026. | Public policy now directly supports a technology capable of both heating and cooling homes. |
| Part O coverage | Applies to new residential buildings in England, not the general existing stock. | Millions of older homes sit outside the main overheating-specific building regulation. |
| Commercial inspection threshold | Systems with an effective rated output above 12kW require inspection at intervals no longer than five years. | Multiple small units under single control can create a compliance duty even when each unit is below 12kW. |
What the New Housing Evidence Actually Shows
The English Housing Survey does not show that every overheating home is installing fixed air conditioning. It shows something more important for construction: the number of households reporting an inability to cool their homes has increased materially, while most residents still depend on basic behavioural measures.
Among the three million households reporting overheating, 90% opened windows, 75% closed shutters, curtains or blinds, and 59% used a fan. Only 7% reported using an air conditioner. The survey explicitly warns that selecting “air conditioner” does not necessarily mean the household owns a permanently installed system.
That qualification matters. Britain is not yet a mature residential air-conditioning market on the scale of hotter countries. The construction signal is that a large unmet cooling need now exists, and government policy is removing some of the financial and planning barriers that previously limited active cooling.
The broader climate context is also becoming harder to dismiss. The Met Office issued amber extreme-heat warnings across much of southern England and the Midlands in June 2026, with temperatures forecast to reach 35°C. This follows the wider pattern examined in LCM’s analysis of why UK heatwaves are becoming a construction delivery risk.
Part O Does Not Solve the Existing-Homes Problem
Approved Document O introduced a dedicated overheating requirement for new residential buildings in England. It requires project teams to limit unwanted solar gains and provide a means of removing excess heat, using passive measures as far as reasonably practicable.
The regulation is important, but its scope is narrow when measured against the scale of the existing stock. Government guidance confirms that Part O does not generally apply to extensions added after a home is built or to buildings undergoing a change of use. It therefore cannot operate as a national retrofit strategy for the millions of homes already experiencing summer discomfort.
Even within new-build design, mechanical cooling is not intended to become the automatic route to compliance. Where cooling is installed, project teams should demonstrate that practicable passive measures have already been incorporated. The cooling installation must also be reflected in the building’s energy calculations because solving overheating through mechanical plant can increase regulated energy use.
This creates an important distinction for developers. The move toward electrified heating under the Future Homes Standard and wider low-carbon building transition does not remove the need for a separate summer-performance strategy. A home can be efficient in winter and still become dangerously hot in summer.
Why Passive Cooling Must Come Before Plant
The strongest cooling strategy usually begins outside the air-conditioning specification. Window area, orientation, glazing performance, external shading, internal blinds, thermal mass, cross-ventilation and secure night purge all affect the size and duration of the cooling load.
The 2026 Warm Homes Plan places unusual emphasis on this sequencing. It identifies passive cooling measures such as solar shading, shutters, reflective window coatings and cooler materials as low-regret interventions that can reduce internal temperatures and make any later active-cooling system work more efficiently.
A London case study included in the plan illustrates the potential scale of the problem. A single-aspect Camden flat recorded bedroom temperatures of 47.5°C when the outdoor temperature reached 28°C. In that monitored example, external shading combined with night-time ventilation reduced indoor temperatures by 11°C to 18°C and eliminated the assessed overheating risk. The result should not be treated as a universal performance guarantee, but it demonstrates how dramatically solar control and ventilation can alter the cooling requirement.
For project teams, this means an air-conditioning quotation should not replace a building-performance assessment. A correctly sized system depends on credible information about solar gain, occupancy, ventilation, internal equipment, façade condition and the resident’s ability to operate windows safely.
Air-to-Air Heat Pumps Are Opening a New Retrofit Market
The policy change with the greatest immediate market effect is the addition of air-to-air heat pumps to the Boiler Upgrade Scheme. Eligible systems can now receive a £2,500 grant. Unlike conventional wet heat-pump systems, air-to-air units distribute heated or cooled air directly and can provide reversible operation across the seasons. Planning barriers have also been reduced. Changes to permitted development rights in England that took effect in May 2025 allowed air-source heat pumps capable of cooling as well as heating to benefit from the regime, subject to the relevant conditions. The changes also removed the former one-metre boundary restriction and increased the permitted unit size for houses. This does not mean every split system can be installed without planning scrutiny. Listed status, conservation controls, lease terms, freeholder consent, appearance, noise, siting and the detailed permitted-development conditions can still affect approval. Flats present an additional coordination challenge because external units, façade penetrations and condensate routes often involve common parts of the building.
The market opportunity is therefore wider than selling indoor and outdoor units. It includes thermal assessment, electrical upgrades, builders’ work openings, fire-stopping, brackets and structural support, acoustic control, façade making-good, condensate drainage, controls, commissioning and ongoing maintenance.
Cooling Demand Will Become an Electricity-Network Issue
The Warm Homes Plan acknowledges that increased active cooling could create new costs and additional pressure on the electricity system. This matters because cooling demand is highly correlated: large numbers of systems can start operating at the same time during the hottest afternoon periods.
At an individual property, a small split system may appear to be a modest electrical load. Across a housing estate, apartment block, office portfolio or mixed-use district, the combined demand can affect incoming supplies, distribution boards, landlord systems and local network assumptions.
The design response should not be to treat every cooling unit as an isolated appliance. Load diversity, simultaneous operation, metering, controls, solar generation, demand response and future electrified heating all need to be considered together. A building already adding EV charging, heat pumps and electric hot water can have less spare electrical capacity than its historic records suggest.
Passive cooling is therefore also an infrastructure measure. Reducing the peak cooling load can avoid or reduce electrical reinforcement, plant oversizing and operating costs. For London developments already exposed to connection and substation pressure, that relationship could become commercially significant.
The Compliance Risks Behind Rapid Cooling Installation
The installation market is governed by several overlapping controls, and rapid growth increases the risk that clients focus on the appliance while missing the wider compliance package.
Building regulations: Government guidance identifies the installation of a fixed air-conditioning system as work that can require building-regulations approval. The installation may affect energy efficiency, electrical safety, ventilation, fire separation and the weather resistance of the envelope.
F-gas competence: People and companies working on stationary refrigeration, air-conditioning and heat-pump systems containing fluorinated gases must hold the relevant qualifications and certification. Clients should verify competence rather than assume that general electrical or plumbing experience covers refrigerant work.
Refrigerant selection: Since 2025, new single-split systems containing less than 3kg of refrigerant cannot be placed on the Great Britain market where the F-gas has a global-warming potential above 750, subject to the stated exceptions. Equipment selection must therefore consider both operational efficiency and the refrigerant regime.
Air-conditioning inspections: In England and Wales, systems with an effective rated output above 12kW must be inspected by an accredited energy assessor at intervals no longer than five years. The threshold can be reached through multiple smaller units under single control.
A 2026 government review recorded that industry feedback collected in 2020 estimated compliance with the inspection requirement at below 20% of in-scope systems. That is not a current measured compliance rate, but it shows that the statutory inspection regime has historically been poorly understood or weakly followed.
What This Means for Contractors, Landlords and Developers
Cooling retrofit is an interface-heavy package. It touches the façade, structure, electrical system, fire strategy, drainage, acoustics, resident communication and maintenance plan. Treating it as a late M&E addition increases the risk of rework and underperformance.
| Delivery Question | Evidence Required | Risk if Missed |
|---|---|---|
| What is creating the heat load? | Orientation, glazing, shading, occupancy, equipment and ventilation assessment. | Oversized plant, high running costs or persistent overheating in untreated rooms. |
| Can passive measures reduce demand? | Options appraisal for shading, films, blinds, secure ventilation and fabric measures. | Mechanical cooling becomes the only control and electrical demand remains unnecessarily high. |
| Where will plant and services go? | Façade survey, structural fixing design, pipe routes, condensate strategy and maintenance access. | Leaks, staining, noise complaints, unsafe supports and inaccessible equipment. |
| Is electrical capacity available? | Load assessment, protective-device review, metering and future electrification allowance. | Nuisance tripping, costly reinforcement or conflict with heat pumps, EV charging and other new loads. |
| Who controls compliance? | Planning, building control, F-gas certification, commissioning and inspection responsibilities. | Invalid installation assumptions, missing records and future transaction or enforcement problems. |
Occupied buildings add a further layer of difficulty. External-unit installation, drilling, ceiling access, shutdowns and commissioning must be coordinated around residents or tenants. The same interface problem is already visible in LCM’s analysis of HVAC and façade sequencing in occupied retrofit projects.
Three Ways the UK Cooling Market Could Develop
| Market Pathway | Likely Delivery Model | Construction Consequence |
|---|---|---|
| Passive-led retrofit | Shading, glazing control and ventilation are installed before active cooling is considered. | Lower peak loads and running costs, but greater façade, planning and resident-coordination input. |
| Integrated heating and cooling | Reversible air-to-air heat pumps are designed alongside passive measures, controls and electrical upgrades. | Creates a scalable specialist retrofit market with year-round use and clearer performance accountability. |
| Unplanned air-conditioning rush | Individual units are installed reactively during heatwaves without a whole-building strategy. | Higher grid demand, inconsistent compliance, façade clutter, noise disputes and repeat remedial work. |
The three pathways are not forecasts. In practice, all will exist at the same time across different tenures and building types. The policy challenge is to prevent the reactive pathway from becoming the default for the households and buildings least able to fund comprehensive adaptation.
LCM Analysis: Britain Is Building a Cooling Market Before It Has Built a Cooling Strategy
The construction opportunity is clear. More homes will need shading, ventilation improvements, heat-pump systems, air conditioning, electrical work and ongoing maintenance. The risk is that the market grows appliance by appliance rather than building by building.
That would reproduce a familiar retrofit failure. The immediate symptom would be treated, while the underlying building performance remains unchanged. Residents would receive cooler air in selected rooms, but the façade would continue absorbing excessive solar heat, secure night ventilation would remain unavailable and the property’s peak electrical demand would rise.
The official figures also reveal a regulatory imbalance. New residential buildings have a dedicated overheating requirement, while millions of existing homes rely on fragmented retrofit decisions, landlord investment, household spending and general housing enforcement. The greatest workload is therefore emerging where the regulatory route is least standardised.
For contractors and consultants, the strongest long-term market will not be basic unit installation. It will be evidence-led cooling retrofit: assess the overheating mechanism, reduce the passive load, verify electrical and structural capacity, install compliant plant, commission the controls and retain a clear maintenance record.
Britain’s air-conditioning boom may still be at an early stage, but the building-performance crisis driving it is already measurable. Three million overheating homes is not a niche consumer trend. It is the beginning of a national adaptation workload.
Frequently Asked Questions
How many English homes are reported as overheating?
The English Housing Survey reported that approximately three million occupied homes became uncomfortably hot and could not be cooled down in 2024, equivalent to 12% of occupied dwellings.
The English Housing Survey reported that approximately three million occupied homes became uncomfortably hot and could not be cooled down in 2024, equivalent to 12% of occupied dwellings.
Does Part O apply to existing homes?
Part O applies to new residential buildings in England. Government guidance confirms that it does not generally apply to later extensions or to buildings undergoing a change of use.
Part O applies to new residential buildings in England. Government guidance confirms that it does not generally apply to later extensions or to buildings undergoing a change of use.
Can air-to-air heat pumps provide air conditioning?
Yes. Reversible air-to-air heat pumps can provide heating in winter and cooling in summer. Eligible installations can receive a £2,500 Boiler Upgrade Scheme grant.
Yes. Reversible air-to-air heat pumps can provide heating in winter and cooling in summer. Eligible installations can receive a £2,500 Boiler Upgrade Scheme grant.
Should passive measures be installed before mechanical cooling?
For new homes under Part O, practicable passive measures should be used as far as reasonably practicable. For existing homes, shading and ventilation can reduce the cooling load and improve the efficiency of active systems.
For new homes under Part O, practicable passive measures should be used as far as reasonably practicable. For existing homes, shading and ventilation can reduce the cooling load and improve the efficiency of active systems.
When is an air-conditioning inspection required?
In England and Wales, an air-conditioning system with an effective rated output above 12kW must be inspected by an accredited assessor at intervals no longer than five years. Multiple smaller units under single control can count toward the threshold.
In England and Wales, an air-conditioning system with an effective rated output above 12kW must be inspected by an accredited assessor at intervals no longer than five years. Multiple smaller units under single control can count toward the threshold.
Sources and methodology: This analysis was compiled from the English Housing Survey 2024–25 weather-resilience fact sheet, the government’s 2026 Warm Homes Plan, Approved Document O and its official frequently asked questions, CIBSE TM59, the Boiler Upgrade Scheme grant notice, the government’s permitted-development update for heat pumps, air-conditioning inspection guidance, F-gas qualification guidance, F-gas equipment restrictions and the Met Office’s June 2026 extreme-heat warning. Construction implications and market pathways are identified as LCM analysis rather than confirmed forecasts.
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Expert Verification & Authorship: Mihai Chelmus
Founder, London Construction Magazine | Construction Testing & Investigation Specialist |
