Guidance on Approved Document O and CIBSE TM59, product updates, and what’s changing in the way we assess overheating risk.
TM59 is the methodology Approved Document O points to for dynamic overheating assessment. It has two tests, and most developments fail the second one. Here is what each measures and what a failure is telling you.
Read articleApproved Document O gives you two routes to compliance. Picking the wrong one costs money twice. Here is how to decide early, and the dwelling types where the simple route almost never works.
Read articleThey sound interchangeable and they are not. One is for homes, one is for everything else, and only one has a night-time bedroom test. A short answer and the reasoning behind it.
Read articleA failed assessment is a diagnosis, not a verdict. Work through the fixes in order of cost and you will usually find one that passes without shrinking a single window.
Read articlePart O made overheating a pass-or-fail gate on new homes in England. What it applies to, what it asks for, and the details that catch people out.
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