Part O of the Building Regulations is concerned with limiting overheating risk in new homes. Air conditioning should not be presented as a standalone route to approval, but it can form part of the wider overheating strategy where the project assessor or design team supports active cooling. We provide cooling specifications and installation documentation for review by the responsible project team.
Part O came into force in June 2022 for new dwellings in England. The assessment is normally led by the project SAP assessor, energy assessor, architect or design team, using either the simplified method or dynamic thermal modelling where required. Our role is to provide suitable air conditioning design information when active cooling is being considered as part of that wider assessment.
Properties with large areas of south or west-facing glazing, upper-floor rooms, open-plan layouts and limited external shading may need closer overheating review. Passive measures should be considered first by the design team. Where active cooling is appropriate, specifying air conditioning at first fix is usually cleaner and easier than retrofitting after completion.
We coordinate directly with your SAP or energy assessor to provide the cooling system specification they need for their Part O calculations. We can advise early in the design process on cooling capacity for your assessor to consider before construction begins.
If your design team is considering active cooling, we can advise on a suitable air conditioning specification and provide documentation for assessor review.
Get a Free QuoteAir conditioning can support a Part O overheating strategy efficiently when it is specified early in a new build.
Active cooling can be considered as part of an overheating strategy, subject to assessment by the project team.
Installed at first fix in a new build, air conditioning can be simpler to integrate than a later retrofit or late-stage design change.
Modern inverter AC systems can provide efficient cooling when correctly specified for the property and expected usage.
Many air conditioning systems can also provide heating, giving useful year-round comfort when specified correctly.
A new build with well-planned comfort cooling can be more attractive to buyers, especially where overheating risk has been considered carefully.
When planned at design stage and installed at first fix, air conditioning can usually be coordinated cleanly within the build programme.
We specify and install air conditioning to support the agreed Part O overheating strategy for new build homes.
Bedrooms are often a key part of overheating assessments. Air conditioning can help manage comfort where the project assessment supports active cooling.
Multi-split systems can form part of a whole-dwelling overheating strategy where the assessment supports active cooling.
Fully concealed ducted AC is ideal for new builds — invisible in the finished property while providing whole-house cooling.
High-wall split units are the most cost-effective Part O solution for individual rooms — quiet, efficient and quick to install.
View all our new build HVAC services — from first fix through to developer packages.
First fix installation during construction means cooling can be planned into the wider Part O strategy early.
Inverter technology delivers efficient, precise temperature control — supporting stable room temperatures in warm weather.
R32 refrigerant systems with lower GWP than older R410A systems.
A clear process from initial review through to assessor and Project documentation.
We review your drawings, identify rooms at overheating risk and advise on cooling capacity for your assessor to consider within the Part O strategy.
We produce a system specification confirming cooling capacities by room — your SAP assessor can use this for the Part O calculation.
We install at first fix and second fix within your construction programme — systems are commissioned and tested before handover.
We provide installed equipment schedules and commissioning records for your project team, ready for assessor review.
Part O of the Building Regulations applies to all new dwellings in England where planning permission was applied for on or after 15 June 2022. It requires the project team to assess and limit overheating risk. It applies to houses and flats of all sizes and types.
Not automatically. Active cooling can help address overheating where passive measures are insufficient, but it needs to be incorporated into the formal Part O assessment by your SAP assessor or design team. We can provide a system specification to your SAP assessor that they can incorporate into the calculation.
Bedrooms, particularly on upper floors and in rooms with south or west-facing windows, are most likely to fail Part O criteria. Open-plan living areas with large glazed areas or limited external shading are also at high risk. We assess each room individually and specify the appropriate cooling capacity.
We provide an equipment schedule listing installed units and their cooling capacities, commissioning records confirming the systems are operational, and F-Gas documentation. These can be supplied to your SAP assessor or design team alongside the Part O calculation.
Request a free survey or ask a technical question. We'll confirm the right next step for your property.
Get a Free Quote