Electrics and gas
Does a home survey test the bathroom extract fan?
No. The surveyor may see a fan, hear it if they switch it, or see that it is painted shut. That is not a flow-rate test and not Approved Document F compliance. Approved Document F is the England ventilation document for building work. A fan that exists is not proof the house is adequately ventilated, and a missing fan is not automatically rising damp.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Condensation and mould in a windowless bathroom often follow a fan that does not extract to outside, or a fan that recirculates. The survey can sometimes see the grille and not the duct. Say so. Do not call the wall a failed damp-proof course because the mirror is wet.
A electrician or a ventilation installer can test or replace a fan. There is no RICS price for that. If the fan was part of a recent bathroom, the competent-person paperwork is the solicitor’s question. The survey does not notify building control.
What should you ask your surveyor?
- Did the fan run, and did you see where it discharges?
- Is there mould, or only a fan that looks old?
- Are you linking this to condensation rather than rising damp?
What are the typical next steps?
- Check the fan discharges outside, not into the loft, once you can do that safely.
- Do not buy a damp-proof course for a wet bathroom mirror.
- Ask an electrician if the fan does not run. Do not expect the survey to have measured litres per second.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Is a trickle vent a substitute for a fan in a windowless room?
Not as a rule this page will invent. A windowless bathroom usually relies on mechanical extract. Ask the person who quotes the fan.
Does a noisy fan mean it passed?
Noise means it made a noise. It does not prove the duct is connected.