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Aipedia: Building services engineers
AI can speed up Part O overheating studies for new homes, but the engineer must own the assumptions on occupancy, ventilation and window opening. Overheating affects occupant health, and failures found late can force costly redesign of facades and ventilation.
Part of: AI in building services engineering
In short
Part O of the Building Regulations covers overheating in new residential buildings in England. Engineers increasingly use AI to set up thermal models, choose weather files and occupancy profiles, and draft overheating reports. The risk lies in assumptions: windows that cannot really be opened, unrealistic shading, missing noise or security limits. Part 2A regulation 11K requires the design to comply if built, and CIBSE Code clause 4.2 requires competence. Overheating claims tend to bring redesign and remedial costs. PI usually responds to negligent design claims, subject to the policy terms.
Approved Document O gives guidance on the overheating mitigation requirements in Part O of Schedule 1 to the Building Regulations, which applies to new residential buildings in England. AI tools are now used to build thermal models from drawings, assign occupancy and internal gains, set window opening and shading, choose weather data, iterate glazing and ventilation options until the scheme passes and write the report for building control.
Overheating work often sits with the MEP engineer because ventilation strategy, mechanical cooling and services heat gains all feed the result.
On higher-risk residential buildings, regulation 38 of SI 2023/909 lists overheating protection among the information handed over on completion.
AI tools tend to optimise towards a pass. That can mean assuming windows open further or more often than noise, security or fall protection allow, applying shading that the architect has not drawn, or using internal gains that ignore communal heating pipework in corridors. The report reads well and the scheme passes, but the building as built may not.
Illustrative scenario: an AI-assisted study for a block of flats passes on the basis of large openable windows. Late in design, acoustic constraints from a nearby road mean windows must stay closed at night. The study is not re-run. Building control queries the assessment near completion, mechanical ventilation and facade changes are needed, and the developer claims redesign and delay costs from the engineer.
A reviewer should look past the pass or fail result to the model itself. Check that the geometry matches the latest drawings, that the worst-case dwellings and orientations have been modelled, that corridor and communal heat gains are included where there is communal heating, and that ventilation and window opening match what the architect and acoustic consultant have agreed. Ask what the tool changed during iteration: if it added shading, reduced glazing or increased ventilation to reach a pass, each change has to be something the design team has actually adopted. A study that passes only because the tool changed the building is not a study of the building being built.
Overheating claims usually allege that the design or assessment was negligent, and PI commonly responds subject to the policy terms. Where residents complain of health effects, claims may also involve other parties and insurance. The M&E specification scenario shows how performance-related design claims develop, and our guide to fitness for purpose versus reasonable skill and care helps you see where your appointment's wording widens your liability. Keeping the assumptions and the version history of each study is often decisive in defending a claim.
Related: AI Part L modelling, AI load calculations and AI and the golden thread. Back to AI in building services engineering.
Apex arranges PI for building services engineers. A broker reviews your cover and how your policy treats AI-assisted overheating and ventilation studies.
No. Approved Document O gives guidance on Part O, which applies to new residential buildings in England. Other building types may still raise overheating questions under contracts or other guidance.
It can propose them, but the designer must check they are realistic once noise, security and fall protection are considered. Assumptions the building cannot meet in use can cause later problems.
The assumptions the pass relies on, especially any limits on window opening, shading or ventilation. Part 2A regulation 11K requires sufficient design information for others to build and operate the design as intended.
PI usually responds to claims alleging negligent design or assessment, subject to the wording. Claims by residents may involve several parties and insurers, so early notification to your insurer matters.
Tell us about your firm and the work you do. A broker will review how your current PI treats AI-assisted work, or arrange new cover. No fee for a quote. Or call 0117 325 0027.
Start a PI quote Request a callbackApex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority. Registered in England and Wales, company number 07014570. This page is general information about how AI is used in the profession and how insurance may respond. It is not legal, regulatory or insurance advice on your circumstances, and it does not guarantee that cover will be available or on what terms.
