Do I need an overheating assessment?
If you are building new homes, yes — Approved Document O applies to all new residential buildings, and many councils (led by the London boroughs) now ask for an overheating risk assessment at planning stage too. Conversions are generally outside Part O, but a planning condition can still require an assessment.
What is the GHA early-stage tool?
A recognised screening tool from the Good Homes Alliance that scores a scheme’s overheating risk factors — location, glazing, orientation, ventilation, communal heat — into a published Low, Medium or High banding. It is designed exactly for planning stage, before detailed design is fixed, and is what many validation lists mean by an “overheating risk assessment”.
What is the difference between the simplified method and TM59?
The Approved Document O simplified method is a table-based check on glazing areas and opening free areas — quick, and sufficient for many houses and dual-aspect flats. CIBSE TM59 is full dynamic thermal modelling, required where the simplified method cannot apply (many flats, high glazing, noise-restricted windows). Our report runs the simplified route and tells you honestly if your scheme needs the dynamic one.
What is a “high-risk location”?
Approved Document O classifies certain postcode areas — significant parts of central and inner London — as higher overheating risk. Schemes there face tighter glazing limits and an explicit duty to consider shading. We screen your exact postcode as part of the assessment.
What if my scheme fails the check?
Failing the simplified method is a design prompt, not a dead end: reduced or reoriented glazing, external shading, solar-control glass or improved cross-ventilation usually recover compliance — and are far cheaper on paper than after a refusal. The report sets out the options in the order the cooling hierarchy expects.
Which areas do you cover?
Every UK local authority — the methods are national, with the location classification built in.
