Best Humidity Monitors
A humidity monitor is a small, cheap device that tells you how damp the air in a room really is. Keeping an eye on it lets you act early — ventilate, run a dehumidifier, or change how you dry laundry — before condensation and mould get a foothold.
For a flat prone to damp, a smart monitor that logs humidity over time and alerts you when it climbs is especially useful, because problems often build up gradually before you notice them.
QUICK ANSWER
A humidity monitor shows your room’s relative humidity so you can act before condensation and mould appear — aim for 40–60%. A basic digital monitor is fine for spot checks; a smart Bluetooth model logs trends and alerts you when humidity climbs.
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Who this guide is for
Anyone in a damp-prone flat who wants to track humidity and catch problems early, especially across several rooms.
Our picks at a glance
| Pick | Best for |
|---|---|
| Govee Bluetooth Hygrometer | Tracking humidity trends and getting alerts |
| SwitchBot Meter | Monitoring several rooms from one app |
| ThermoPro TP49 Digital Hygrometer | A simple, cheap humidity readout |
Our picks in detail
BEST SMART — Govee Bluetooth Hygrometer
Best for: Tracking humidity trends and getting alerts
Connects to your phone to log humidity over time and alerts you when it rises too high — ideal for spotting a damp problem before you can see it.
Pros: App logging, high/low alerts, accurate.
Cons: Needs the app for the full benefit.
BEST FOR MULTIPLE ROOMS — SwitchBot Meter
Best for: Monitoring several rooms from one app
Small smart sensors you can place around the flat and read from a single app — handy when damp shows up in more than one room.
Pros: Cheap per unit, app view, expandable.
Cons: Best value bought as a set.
BEST BASIC — ThermoPro TP49 Digital Hygrometer
Best for: A simple, cheap humidity readout
A tiny display showing temperature and humidity with a comfort indicator — cheap enough to put one in every room.
Pros: Very cheap, clear display, tiny.
Cons: No logging or phone alerts.
Prices and availability on Amazon are accurate as of the date of publication and are subject to change.
How to choose
- Healthy target: keep rooms around 40–60% relative humidity.
- Logging vs spot check: a smart monitor shows how humidity changes through the day.
- Alerts: useful to catch a rising damp problem early.
- Placement: away from windows, radiators and the kitchen for a fair reading.
- Multiple rooms: monitor the bedroom and bathroom area, which get dampest.
- Act on it: a monitor only helps if you ventilate or dehumidify when it reads high.
Common questions
What humidity should a flat be?
Around 40–60% relative humidity is a healthy target. Above 60% for long periods encourages condensation and mould, so a monitor helps you know when to ventilate or dehumidify.
What is the difference between a humidity monitor and a hygrometer?
They are the same thing — a hygrometer is simply a device that measures humidity. Smart versions add logging and phone alerts on top of the basic reading.
Are cheap humidity monitors accurate enough?
For spotting trends and knowing when a room is too damp, yes. They are not lab instruments, but they are more than accurate enough to guide ventilation and dehumidifier use.
How many do I need?
One in each room that tends to get damp is ideal — usually the bedroom and bathroom area. They are cheap, so monitoring a few rooms is easy.
Our recommendation
For most flats a smart Bluetooth monitor like the Govee is worth the small extra over a basic unit, thanks to logging and alerts. For several rooms, SwitchBot sensors are handy; a ThermoPro TP49 covers basic spot checks.