Damp and moisture meters
A positive-input fan sits in the hall ceiling. Has the home survey tested that unit, or only recorded that it is fitted?
The home survey has only recorded that a positive-input fan is fitted in the hall ceiling. It has not tested the unit. A box or grille on the ceiling is not a trial of the fan, the filter, the loft intake or the controls. The visit did not measure the air being pushed into the hall, did not run a cycle, and did not decide whether this is the right way to ventilate the house. What is known is that the equipment is there. What is not known is whether it works.
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?
A positive-input unit draws air, usually from the loft or from outside, and blows it into the circulation space so rooms are slightly pressurised. That only happens if the fan runs, the filter is clear and the intake is open. Seeing a ceiling diffuser confirms the hardware. It does not confirm the motor, the duct in the loft or the control setting. The survey should keep the sentence as fitted equipment. It should not upgrade a glance into a working system.
If you need to know whether the unit performs, that is a separate check by someone who will switch it on, listen to it and look at the intake. Pass any seller claim that the system cures condensation to that person, not back to the survey. The solicitor does not need a ventilation redesign. They need to know the survey has not certified the fan, so a reply that it was recently serviced can be asked for as a paper, not assumed.
What should you ask your surveyor?
- Did you only see the ceiling unit, or did you see it running?
- Was the loft intake, filter or control inspected?
- Have you left performance untested rather than implied by the fitting?
What are the typical next steps?
- Record the hall unit as fitted, not as tested.
- Do not treat a ceiling grille as proof the fan works.
- Commission a separate check if you need the unit run.
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
If the fan was humming on the day, does the hum count as a test?
A hum shows the motor made a noise while you were there. It does not measure how much air moved, whether the filter was blocked, or whether the intake in the loft was clear. The survey still has not tested performance.
Does this hall fan replace the need for extract fans in wet rooms?
The survey has not decided that. A unit in the hall is one arrangement. Extract from a bathroom or kitchen is another. Seeing the hall fan does not show those extracts are unnecessary, and it does not show they were tested either.