Humidity monitoring means placing small sensors in the rooms most at risk of mould and recording humidity and temperature over days or weeks. The readings show when and where condensation risk peaks, whether ventilation is working, and whether a repair has made a difference. It helps residents, landlords and housing providers choose the right fix and check it afterwards.
Why monitor humidity at all?
A single visit gives a snapshot. Condensation is a pattern: humidity rises after showers, cooking and overnight in bedrooms, and surfaces cool when heating goes off. Mould grows where the two meet often enough. Monitoring records that pattern over time, which turns “it always seems damp in here” into evidence that can guide a decision.
Persistently high indoor relative humidity, often quoted as staying above around 60–70%, encourages condensation and mould. The figure that matters most is how long a room stays humid and how cold its walls and windows are. Sensors that log both humidity and temperature let us estimate when surfaces are likely to reach the dew point.
Who is monitoring useful for?
- ResidentsSee whether a bedroom or bathroom is staying humid for hours, and what difference opening trickle vents or running the fan longer actually makes.
- Private landlordsGet clear readings before and after work, alongside written notes and photos. Our landlord damp and mould page covers the wider picture.
- Housing providersCheck that remedial work has worked when re-inspecting, which the 2023 Government guidance on damp and mould encourages. See social housing and Awaab’s Law.
- Homes after treatmentConfirm that new ventilation, such as a fan or PIV unit, is bringing humidity down in the rooms that had mould.
What monitoring is not
Monitoring is a way to understand a problem, not a way to judge the people living in a home. Moisture comes from everyday life – cooking, washing, bathing, drying clothes and breathing – and the job of a home’s ventilation and heating is to cope with it. Readings are never used to blame residents. UK Government guidance published in September 2023 tells landlords not to put mould down to tenants’ “lifestyle” and to deal with the underlying causes. We use data to find which room, which time of day and which part of the building needs attention.
How our humidity monitoring works
- Initial conversation. We ask where mould has appeared, how long for, whether it is worse in winter, who lives in the home (including anyone vulnerable), and whether it is owned or rented.
- Visit and placement. We look at the affected rooms, take spot readings and check fans, trickle vents and heating. Sensors go in the rooms that matter, usually a bedroom, bathroom and kitchen, plus one in a drier room for comparison.
- Recording period. Sensors usually stay for a week or more so the readings cover a normal routine. Longer periods help in colder months or where there is a before-and-after comparison.
- Reading the results. We look at peaks, how quickly rooms recover after showers or cooking, overnight levels in bedrooms and how temperatures fall when heating is off.
- Plain-English findings. You receive written findings with simple charts and photos, the likely cause, and what we recommend.
- Re-check after work. Where work is done, a second recording period shows whether humidity has come down.
What can the results lead to?
Monitoring often points clearly to one of a handful of fixes. A bathroom that stays humid for an hour after a shower may need a better fan, a longer overrun or a door undercut; our extractor fan installation page explains Part F extract rates. Bedrooms that climb overnight across the whole house often suit whole-house background ventilation such as positive input ventilation. Rooms where windows have no background vents may need trickle vents fitted. If readings are normal but a wall stays wet, the problem is likely a leak or penetrating damp rather than condensation, and we change course.
| Pattern in the data | What it often suggests |
|---|---|
| Sharp peaks after showers that fall slowly | Bathroom extract too weak, short overrun or no air path in |
| Bedroom humidity rising steadily overnight | Low background ventilation; closed or missing trickle vents |
| High humidity across the whole home | Whole-house ventilation shortfall; drying clothes with nowhere for moisture to go |
| Normal humidity but a wet, cold wall | Penetrating damp, a leak or a cold spot rather than general condensation |
Monitoring in Liverpool homes
Different housing gives different patterns. Post-war houses and maisonettes in Kirkby and council-built estates in Huyton often have small kitchens and bathrooms where moisture builds up quickly. Victorian terraces and older flats in Bootle combine solid, cold walls with back-extension bathrooms. Monitoring helps separate a room that needs better extraction from a wall that needs repair. It sits alongside our wider mould removal in Liverpool and condensation control work.
What affects the cost of humidity monitoring?
Cost depends on how many rooms and sensors are needed, how long the recording period runs, whether a second, post-work period is needed, and how detailed a written report a landlord, agent or housing provider wants. If mould removal or ventilation work follows, that is quoted separately. See our damp and mould cost guide for the factors behind those jobs.
If anyone in the home has asthma, other breathing problems or a weakened immune system, do not wait for monitoring results to deal with visible mould. Speak to your GP or NHS 111 about symptoms, and ask a local damp and mould specialist to look at the mould itself straight away.
Want to know why one room keeps getting mould?
Call 07777 659786 or leave your details. Tell us which rooms are affected and whether the home is rented, and we will call you back to talk through monitoring and next steps.
Frequently asked questions
What humidity level causes mould?
There is no single number, because mould depends on how cold surfaces are and how long they stay damp. Indoor humidity that stays above around 60–70% for long periods often goes with condensation and mould, especially on cold external walls and windows. Short peaks after a shower are normal; what matters is whether the room recovers quickly.
Can I monitor humidity myself?
Yes. An inexpensive hygrometer or a smart sensor in a bedroom and bathroom can show useful patterns. Note the reading in the morning and after showers or cooking. Professional monitoring adds surface temperature checks, a look at the fans, vents and heating, and written findings that a landlord or housing provider can act on.
Do the sensors record conversations or video?
No. Humidity monitoring sensors record humidity and temperature only; they do not need cameras or microphones. We explain where each one is placed and how long it will stay, and residents are told before any monitoring starts in a rented home.
Will a dehumidifier fix the problem?
A dehumidifier can help a single room, especially when drying clothes indoors, and may be a useful short-term measure. It does not fix weak extraction, missing background ventilation or a leak. Monitoring shows whether a longer-term fix is needed, such as a better fan, trickle vents or whole-house ventilation.
How long should humidity be monitored?
Usually a week or more, so the readings cover a normal routine of cooking, washing and sleeping. In colder months, or when comparing before and after a repair, a longer period gives a clearer picture. We agree the period with you, your landlord or your housing provider before sensors go in.