Ventilation is one of the least glamorous parts of a home, but it is also one of the most important.
Most people only think about ventilation when something has already gone wrong. Mould appears around the bathroom ceiling. Black spotting forms behind furniture. Paint peels near a window reveal. A kitchen fan sounds like it is working, but condensation still runs down the glass. A downstairs WC has no extract fan at all. A bathroom fan switches on, but nobody knows where the duct actually goes.
Ventilation defects rarely sound dramatic in a property report. They are not as eye-catching as cracks, damp or roof leaks. But poor bathroom and kitchen ventilation can make an otherwise ordinary home feel damp, stale and unhealthy. It can also make buyers nervous because mould and condensation are often misunderstood.
That is why Survey Shack has included ventilation and basic checks within the new Services category.
We do not expect owners or buyers to become ventilation designers. We do think they can understand the basics: whether extraction is present, whether it appears to work, whether moisture is being controlled and whether the air is actually being taken outside.
Ventilation Is Not Just Opening a Window
Opening a window can help purge stale or moist air, but it is not the same as proper extract ventilation in moisture-producing rooms.
Bathrooms, kitchens, utility rooms and WCs create moisture, odours and airborne pollutants. Building Regulations guidance in England is contained in Approved Document F, which deals with ventilation.
For dwellings, Approved Document F gives minimum extract rates for rooms such as kitchens, utility rooms, bathrooms and sanitary accommodation. The current 2021 edition, which came into force in 2022, gives intermittent extract rates including 30 litres per second for a cooker hood extracting to outside, 60 litres per second for a kitchen extract fan elsewhere, 15 litres per second for a bathroom, 30 litres per second for a utility room and 6 litres per second for a sanitary room.
Those figures are useful because they show the principle: wet and odour-producing rooms need proper extraction.
But Survey Shack is careful with this. A visual assessment does not prove that a fan meets Approved Document F. Seeing a fan on a wall is not the same as measuring performance, checking the duct route, confirming compliance or verifying how the system was designed.
That is exactly the gap our app is built to explain.
What Can a Surveyor Actually Check?
A surveyor can see whether a fan is present. They can identify visible mould, staining, condensation, blocked vents, sealed trickle vents, missing extract fans or obvious poor discharge arrangements. They may also be able to hear a fan running.
But they are not usually carrying out a ventilation performance test. They are not normally calculating airflow rates or opening ceilings to trace duct routes. Nor are they confirming whether a fan discharges outside unless this is visible or otherwise evidenced.
For a wider look at what a surveyor typically assesses during a property inspection, read our guide to What Does a Surveyor Look For During a House Survey?
So when a survey report says ventilation needs improvement, the real question is: what was actually seen?
Was there no fan? Was the fan not working? Was there visible mould? Was the fan noisy or weak? Was the duct route unknown? Was the fan discharging into a loft or ceiling void? Were vents blocked or painted shut? Or was the surveyor simply unable to confirm performance from a visual inspection?
Those are different concerns.
A missing fan in a windowless bathroom is not the same as a fan that appears to work but has no visible external grille. Visible black mould around the ceiling is not the same as a lack of paperwork for a recently installed extractor.
Understanding that difference matters.
What Homeowners and Sellers Can Check Before Marketing
For owners and sellers, ventilation is one of the easiest service areas to check before a sale.
Look at the bathrooms, kitchen, utility room and WCs. Does each moisture or odour-producing room have a sensible means of ventilation? Does the fan switch on? Is it noisy, weak or clogged with dust? Does it continue running on an overrun timer where expected? Is there obvious mould or condensation staining? Can you see an external grille or roof terminal showing that the fan discharges outside?
Clean dirty fans and vents. Replace broken or weak fans where appropriate. Check whether trickle vents have been sealed, painted shut or blocked. Make sure extractor grilles are not choked with dust. If a fan has been installed recently, keep the invoice, specification, installation record or electrician’s paperwork.
If a bathroom fan discharges into a roof void rather than outside, that should be dealt with. Warm, moist air pushed into a cold roof space can create condensation and increase the risk of timber decay.
Planning Portal guidance for kitchens and bathrooms says any new kitchen, bathroom, shower room, utility room or toilet should have extract ventilation to reduce condensation and remove smells. It also says that when refurbishing a kitchen or bathroom, existing extract ventilation should be retained or replaced.
For sellers, good ventilation evidence helps. If a buyer’s survey notes visible mould, a missing fan or an uncertain discharge route, it may cause avoidable concern.
If the fan is clean, working and properly ducted, and there is no visible moisture problem, the buyer starts from a much better position.
Understanding your property’s condition before it reaches this stage can also help you prepare for other questions a buyer may raise. Read Should You Check Your Property’s Condition Before Selling?
What Buyers Should Check About Ventilation
For buyers, ventilation concerns should be read carefully.
A survey report may say “ventilation inadequate” or “improve ventilation”, but that phrase can cover several different issues.
Ask what was actually recorded. Was there visible mould? Was mechanical extraction missing? Was the fan not working? Was the discharge route not visible? Were trickle vents blocked? Was condensation present on the day of inspection?
Then ask for evidence. If extractor fans have been installed recently, is there an invoice or specification? If a bathroom or kitchen has been refurbished, was ventilation retained or upgraded? If there is a windowless bathroom, how is moisture extracted? If there is a cooker hood, does it extract outside or simply recirculate through a filter?
A recirculating cooker hood may help with grease and odour, but it does not remove moisture from the building in the same way as external extraction. That distinction can matter in small kitchens, flats and homes that already show condensation issues.
Buyers should also remember that mould is not always caused by one thing. It can involve ventilation, heating, insulation, cold bridges, leaks, occupation patterns and furniture placement.
Poor ventilation may be part of the story, but it is not always the whole story.
Ventilation is just one part of understanding a home before committing to a purchase. Our guide to How to Check a Property’s Condition Before Buying explains what else buyers can start looking at earlier.
How Survey Shack Helps You Check Ventilation
Survey Shack does not certify ventilation systems or replace a ventilation specialist.
Instead, it helps owners and buyers record the visible and practical evidence that usually matters first.
That includes whether a fan is present, whether it appears to switch on, whether the room has a window, whether there is visible mould or condensation staining, whether trickle vents are present or blocked, whether an external discharge point can be seen, and whether there is evidence of recent installation or maintenance.
It also helps identify where the answer is simply unknown.
For example, a bathroom fan may switch on, but the route of the duct may not be visible. That does not prove the fan is defective, but it does mean the discharge route has not been confirmed.
A kitchen hood may be present, but it may recirculate rather than extract to outside. That does not make it useless, but it changes what it can do.
This is where simple guided questions can be more useful than vague wording. The aim is to separate a visible defect, missing evidence, an access limitation and something that genuinely requires specialist testing.
Why Survey Shack Uses Purple for Ventilation
Ventilation is a good example of why Survey Shack uses Green, Yellow, Purple and Red.
Green may be appropriate where suitable ventilation is present, appears functional, no obvious mould or condensation concern is recorded, and the discharge arrangement is reasonably evidenced.
Yellow may be appropriate where maintenance is needed, such as a noisy fan, dirty grille, blocked vent or minor condensation issue.
Purple is useful where something appears to be present but cannot be properly confirmed. A fan may switch on, but the outlet is not visible. A bathroom may have an extractor, but no one knows where it discharges. A kitchen may have a hood, but it is unclear whether it extracts externally or recirculates.
The visible condition may not justify panic, but more evidence is needed before treating it as low risk.
Red is more appropriate where ventilation is missing in a high-moisture room, there is significant visible mould, the fan appears non-functional, or there is evidence that moist air may be discharging into a concealed space.
This is not about making ventilation sound more complicated than it is. It is about explaining uncertainty properly.
When Specialist Ventilation Advice May Be Needed
Where ventilation concerns need specialist input, Survey Shack can point users towards relevant partners such as Fanshawe Group.
That may be helpful where fans need replacement, duct routes need checking, extract systems need improvement, or where ventilation concerns overlap with electrical, heating or above-ground service issues.
The purpose is not to send every owner or buyer to a contractor. It is to help them understand whether they are dealing with a simple maintenance issue, missing evidence, poor installation or something that needs proper specialist assessment.
Good Ventilation Starts With Understanding What Is There
Ventilation problems are often small at the start, but they can create bigger problems if moisture is not controlled.
Owners can reduce concern before marketing by checking fans, cleaning vents, dealing with obvious mould, confirming external discharge where possible and keeping evidence of recent works.
Buyers can make better decisions by asking what a ventilation concern is actually based on: a missing fan, weak fan, visible mould, blocked vents, uncertain duct route or lack of specialist confirmation.
Survey Shack helps both sides understand the visible evidence before a specialist is needed.
A fan on the wall is not proof of good ventilation. A bit of mould is not proof that the whole house is defective. The important thing is to record what is visible, understand what is missing and get the right person involved when the evidence justifies it
