Is Air Conditioning Banned In New Builds?

For anyone worried that air conditioning is being banned, the good news is simple: it’s not true.

But new residential buildings in England must now address the risk of overheating under Part O of the Building Regulations.

Developers are expected to design homes that stay cool naturally before relying on mechanical cooling, such as air conditioning.

So, while AC is allowed in new builds, it should not be the first or only way to deal with overheating.

Why Do People Think Air Conditioning Is Banned In New Builds?

People often get confused because modern building regulations now focus more closely on overheating.

That shift makes sense. According to the Met Office, 2025 was the UK’s warmest year on record, while four of the UK’s five warmest years have now occurred since 2020. The UK has also been warming at around 0.25°C per decade since the 1980s.

As a result, summer comfort is becoming a bigger issue for homeowners, especially in modern properties.

That is where Part O comes in.

Part O was created to lower the risk of overheating in new homes. It does not ban air conditioning.

Instead, it asks developers to plan for overheating from the start, instead of using AC as a quick fix after the home gets too hot.

This is where things can get confusing.

Since the rules focus on limiting heat gain, improving ventilation, and using passive cooling first, some people think mechanical cooling is not allowed.

However, these regulations now require that new homes be designed to passively manage heat build-up.

Another reason for confusion is the focus on energy efficiency.

The UK has a legal target to reach net-zero greenhouse gas emissions by 2050. As a result, new homes are expected to use less energy and produce fewer carbon emissions.

There is also a difference between the rules for building new homes and the rules for what homeowners can do after they move in. Developers must comply with the Building Regulations when the home is built, and can install AC units in the home by following them.

Homeowners are allowed to add air conditioning later, as long as the system is suitable and any planning, lease, noise, or building rules are followed.

Part O focuses on making design choices that keep homes comfortable without relying on mechanical cooling right away.

What Is Part O?

Part O is the section of the Building Regulations that deals with overheating in new residential buildings.

It applies to new homes and certain residential buildings where people sleep, such as flats, care homes and student accommodation.

However, Part O should not be viewed in isolation. It forms part of a wider move toward better, lower-carbon homes in the UK.

For years, building rules have focused heavily on keeping homes warm and reducing heat loss.

That made sense in a country where heating has traditionally been the biggest comfort and energy concern.

As a result, modern homes are now built with better insulation, improved airtightness and stronger energy performance standards.

However, as homes become better at keeping heat in, overheating becomes a bigger design risk.

Add warmer summers, larger windows, dense developments and limited natural ventilation, and some new homes can become uncomfortable during hot weather.

That is where Part O fits in.

The goal is not to stop people from cooling their homes. Instead, it encourages better design from the beginning.

It asks developers to think about summer comfort before the home is built, rather than treating overheating as something to fix later.

Part O sits alongside the UK’s broader environmental goals, including the move toward net zero emissions by 2050 and the push for more energy-efficient housing.

In simple terms, new homes need to perform well in winter and summer.

They should use less energy, produce fewer emissions and still remain comfortable to live in.

Part O checks how likely a building is to overheat and how that risk can be reduced.

Depending on the project, this can be done using a simplified method or more detailed modelling.

This may involve looking at:

• window size and orientation;
• glazing choices;
• solar gain;
• shading;
• ventilation;
• noise and security limitations;
• whether windows can realistically be opened;
• how heat escapes from the building.

For homeowners, the main takeaway is simple:

Part O does not ban air conditioning. It aims to ensure new homes do not rely on AC due to poor design.

In other words, it is not anti-cooling. It is anti-bad planning.

Part O: What Homeowners Need To Know

Part O can sound technical, but the basic idea is simple.

It is part of the Building Regulations that focus on reducing the risk of overheating in new residential buildings.

The official GOV.UK Part O FAQ explains how the rules work in practice, including where Part O applies, how overheating can be assessed, and what happens if mechanical cooling is used.

An Engineer’s View

Part O is not about restricting your choices; it is about ensuring new homes are built smartly to prevent them from becoming saunas in the summer. A properly specified air-to-air heat pump acts as the perfect modern solution to this, handling both extreme summer heatwaves and winter chills.

– Rhys Powell, F-Gas Engineer

For homeowners, the main point is this:

Part O does not ban air conditioning. It asks developers to reduce the risk of overheating through good design first.

Does Part O Apply To All Homes?

No. Part O applies to new residential buildings in England.

Part O does not apply to extensions or conservatories added to homes after construction.

It also does not apply to buildings undergoing a change of use.

However, conservatories on new residential buildings must meet Part O requirements.

So, if you are buying a newly built home, Part O may be relevant.

If you are adding an extension to an existing home, it usually will not apply in the same way.

What Does “Passive Means” Actually Mean?

Passive means are design features that help keep a home cooler without relying on powered cooling equipment.

These can include:

• limiting unwanted solar gain
• using suitable glazing
• adding shading
• designing windows that can open safely
• improving natural ventilation
• helping excess heat escape from the building

Part O wants your home’s design to do some cooling work before an air conditioner is called in.

Can Mechanical Cooling Still Be Used To Pass Part O?

Yes, but it affects the wider building assessment.

However, if mechanical cooling is installed, the SAP calculations must reflect that it is there.

Jargon Buster: SAP (Standard Assessment Procedure)
The government-approved method for assessing and comparing the energy and environmental performance of residential dwellings in the UK.

SAP stands for Standard Assessment Procedure. It is the government-approved method for assessing the energy performance of new homes in the UK.

It looks at how much energy a home is likely to use for heating, hot water, ventilation, lighting, and cooling.

So, if a new home includes mechanical cooling, such as air conditioning, that needs to be included in the assessment.

That matters because adding cooling may affect the building’s compliance with the energy-efficiency requirements of the Building Regulations.

Why Does Part O Focus So Much On Windows?

Windows play a big role in overheating.

Large areas of glazing can let in a lot of solar heat, especially when they face certain directions.

At the same time, openable windows can help remove excess heat, especially at cooler times of day.

This is why Part O looks at things such as glazing area, window orientation, shading and free area for ventilation.

However, it is not just about having windows that open.

The design also needs to consider whether windows can be used realistically.

For example, ground-floor windows, balcony doors or patio doors may not always be suitable to leave open at night for security reasons.

What About Noise, Safety And Security?

Part O also considers how people actually live in their homes.

A ventilation strategy may look good on paper, but it needs to work in the real world.

If windows need to stay open for long periods, designers may need to consider noise, security, and the risk of falls.

In other words, Part O is not just asking, “Can the window open?”

It is asking, “Can someone safely and realistically use this window to help cool the home?”

Why Does This Matter For New Build Homeowners?

Part O matters because new homes are being designed for a warmer climate.

Modern new builds are usually much more energy efficient than older homes.

According to the Office for National Statistics, new dwellings in England and Wales had a median EPC score of 84, which is a band B rating, in the five years to March 2024.

Government figures also show that 85% of new dwellings in England received an EPC rating of A or B between July and September 2024.

That is good news for winter comfort, running costs and carbon emissions.

However, it also means summer comfort needs more attention.

Better insulation, improved airtightness and higher energy standards help keep heat inside during colder months.

But if overheating has not been properly planned for, some homes may also retain unwanted heat during summer.

Overheating is not just a theoretical problem either. An Arup report for the Climate Change Committee found that, under current weather conditions, around 55% of the UK housing stock, or 15.7 million homes, failed the bedroom overheating criterion.

That is why a well-designed new build should reduce heat gain, allow excess heat to escape and stay comfortable without relying too heavily on mechanical cooling.

However, that does not mean every home will stay cool enough in every situation.

Some properties may still benefit from a properly sized fixed AC system, especially bedrooms, home offices, loft rooms or south-facing spaces.

Does Air Conditioning Count As A Heat Pump?

Yes, in many cases.

A modern split air conditioning system is usually an air-to-air heat pump.

This means it does not create heat in the same way as a traditional electric heater.

Instead, it moves heat from one place to another.

In summer, it removes heat from inside your home and moves it outside.

In winter, many systems can reverse the process and bring heat into the room.

That is why modern air conditioning is becoming more important for UK homes.

It can help solve two problems at once.

First, it can provide cooling during warmer summers, especially in bedrooms, loft rooms, home offices and south-facing spaces that hold heat.

Second, it can provide efficient room-by-room heating during colder months.

This can be useful in homes where one room needs extra warmth without turning up the heating across the whole property.

This is where air-to-air heat pumps become particularly relevant. They give homeowners more control over individual rooms rather than treating the whole house as a single temperature zone.

For example, a home office may need cooling during the day due to sunlight, laptops, and screens.

A bedroom may need cooling at night during summer. Then, in winter, those same rooms may benefit from quick, efficient heating without relying entirely on the main central heating system.

However, air-to-air heat pumps do have limits.

They do not usually provide domestic hot water. So, they are not always a direct replacement for a boiler or a full wet central heating system.

Instead, they often work best as part of a wider home comfort setup.

For many homeowners, that makes modern AC less of a summer luxury and more of a flexible heating-and-cooling system.

It can help manage overheating, improve room comfort and support more efficient energy use when chosen and installed correctly.

What About The Future Homes Standard?

The Future Homes Standard is expected to push new homes toward lower-carbon heating and higher energy performance.

This is part of a broader shift away from fossil-fuel heating in new homes.

As homes become more efficient and use more electricity, cooling may also become a bigger topic.

That does not mean every new home will automatically come with air conditioning.

However, it does mean homeowners may start to think differently about heating and cooling.

Modern AC is not just about staying cool during a heatwave.

Many fixed air conditioning systems are air-to-air heat pumps, which means they can cool rooms in summer and provide efficient heating in colder months.

That makes them useful for homeowners who want more control over specific rooms, such as bedrooms, home offices, loft spaces and south-facing living areas.

There is also a timing point to consider. The current 0% VAT relief on the installation of certain energy-saving materials is due to end on 31 March 2027. After that, installations are expected to return to the reduced VAT rate of 5%.

So, if you are already considering installing a modern air conditioning system, it may be worth exploring your options before the VAT window closes.

WarmZilla Makes Finding The Perfect AC Unit, Easy!

We make it easier to compare fixed air conditioning systems, understand what your home actually needs and get a professional installation from qualified engineers.

Whether you want to cool a bedroom, make a home office more comfortable, or add heating and cooling to several rooms, WarmZilla can help you find a system that suits your property via our easy-to-complete survey.

Get your free online air conditioning quote today and see how much it could cost to make your home more comfortable before the 0% VAT window comes to an end.

Frequently Asked Questions

Is Air Conditioning Banned In New Build Homes?

No. Air conditioning is not banned in new-build homes.

However, new residential buildings in England must address overheating risk under Part O of the Building Regulations.

This means developers should consider passive cooling, ventilation, shading and solar gain before relying on mechanical cooling.

Can A New Build Still Have Air Conditioning Under Part O?

Yes. A new build can still include air conditioning.

However, if mechanical cooling is used as part of the overheating strategy, it must be reflected in the building’s SAP calculations.

This can affect the home’s wider energy-efficiency assessment.

Does Modern Air Conditioning Also Work As Heating?

Yes, many modern fixed split air conditioning systems are air-to-air heat pumps.

They can cool a room in summer and provide heating in winter by moving heat rather than generating it directly.

However, they usually do not provide domestic hot water, so they are not always a full replacement for a boiler or wet central heating system.