Property Ventilation Audit Checklist
Twenty minutes, room by room: test what extracts, what vents, and what's sealed shut — and find exactly where this winter's condensation will come from before it arrives.
How do I audit my home's ventilation? Room by room, testing rather than assuming: wet rooms (does extraction actually pull — the paper test — and duct outside?), habitable rooms (trickle vents present, openable and open? airflow behind furniture on external walls?), circulation (door undercuts letting air move?), and the building itself (airbricks clear along suspended floors, loft ventilation unblocked, PIV unit filters clean if fitted). Most North London homes fail in two or three predictable places — sealed bedrooms, token extraction, buried airbricks — and each failure maps to a fix from £20 (trickle vent) to £800–£1,500 (PIV).
Use the checklist
Walk the home with your phone or a printout. The paper test: a sheet of paper held to a running extractor grille should stick firmly.
Bathroom & kitchen (the moisture sources)
Habitable rooms
The building itself
Score and act
Related services and guides
Ventilation Solutions (PIV)
The service this tool points toward — diagnosis-first, independent qualified providers.
View the serviceSubfloor Ventilation
The service this tool points toward — diagnosis-first, independent qualified providers.
View the serviceVentilation Guide: PIV, Extractors and Condensation Control
The in-depth guide behind this tool's logic.
Read the guideThe Complete Guide to Condensation and Mould
The in-depth guide behind this tool's logic.
Read the guideProperty Ventilation Audit Checklist FAQs
Hold a sheet of paper flat against the running extractor grille: working extraction pins it firmly; paper that flutters or falls means the fan is decorative — blocked duct, dead motor or hopeless flow rate. It's the single most revealing 10-second test in this audit.
Very much: you're exporting the bathroom's moisture into a cold void where it condenses on the roof timbers — trading bathroom mould for loft condensation and eventual timber trouble. Re-ducting to outside is a modest job that prevents an expensive one.
Find them (low on external walls with suspended floors), confirm they're unobstructed by paving, soil, render or paint, and check air genuinely passes (a tissue held close should stir). Buried airbricks are North London's commonest ventilation defect — restoration runs £150–£900.
Cheapest-per-impact first: open/fit trickle vents, fix extraction in the wet rooms, clear airbricks — then reassess. If mould persists whole-home after those, that's the PIV signature; the ventilation guide takes it from there.
Want a professional answer, not just an estimate?
Call today or book a survey — the right independent qualified specialist, matched to your property.