Buying Guide
How to Use a Dehumidifier Effectively — UK Guide
Updated July 2026
Bought a dehumidifier but not sure you're using it right? You're not alone. Most UK owners leave it on maximum in an open-plan room and wonder why their electricity bill rises but the damp doesn't improve. The secret is simple: close the door, set the humidistat, and place it correctly. Here's how to get maximum moisture extraction for the minimum electricity cost.
Quick answer
Our top pick: The 3 golden rules
No cost on Amazon
1) Close all doors and windows in the room. 2) Set humidistat to 50–55% RH. 3) Place in the centre of the room, not against a wall. These 3 changes can double your dehumidifier's effectiveness overnight.
Check Price on Amazon →Where to place your dehumidifier
- In the centre of the room where air can flow around it on all sides.
- At least 30cm away from walls so the intake grille isn't blocked.
- Not behind or under furniture — sofas, beds and curtains all block airflow.
Air needs to flow freely into and out of the dehumidifier. Placing it in a corner or behind furniture blocks airflow and can reduce extraction by up to 50%. If the centre of the room isn't practical, choose an internal wall (not an external one) with clear space in front and above the unit.
Best settings for UK homes
- Humidistat: 50–55% RH for living areas, 45–50% for bedrooms.
- Fan speed: auto or medium — quiet and efficient. High speed only helps in very damp rooms.
- Laundry mode: only when actively drying clothes. Switch back to normal after — laundry mode ignores the humidistat and runs continuously.
- Timer: 6–8 hours a day is enough for most UK homes with the humidistat cycling on/off.
When to run your dehumidifier
| Situation | When to run |
|---|---|
| Bedroom | Overnight OR 2 hours before bed + 2 hours after waking |
| Living room | Evenings — when you produce the most moisture |
| After cooking | 1–2 hours with the kitchen door closed |
| After showering | 1–2 hours with the bathroom door closed |
| Drying clothes | Entire drying cycle with the door closed and laundry mode on |
7 common dehumidifier mistakes
- Running with windows and doors open — moisture pours in from the rest of the house faster than the machine can remove it.
- Never cleaning the filter — reduces extraction 30–50% and increases electricity use.
- Setting the humidistat too low (35–40%) — machine runs constantly, wastes electricity and dries out furniture.
- Placing against a wall or in a corner — starves the intake grille of air.
- Ignoring the full tank warning — the machine stops until you empty it, doing nothing while damp builds up.
- Not using the continuous drainage option — for basements or laundry rooms, run a hose to a drain and never empty a tank again.
- Using a mini Peltier dehumidifier for a full room — they extract 250ml/day, a room needs 6L+/day.
How to clean your dehumidifier filter
- Slide the filter out (usually at the back or top).
- Rinse under a cold tap until the water runs clear.
- Air dry fully before refitting — never use a hair dryer on high heat.
Do this every 2 weeks in normal use, every week if the room is very dusty or you have pets.
Quick reference: get more from any dehumidifier
Close the door
Dehumidifying one room with a closed door is 3× more effective than dehumidifying the whole house with doors open.
Set humidistat to 50%
The sweet spot for UK homes — dry enough to stop mould, not so dry it wastes electricity.
Clean the filter fortnightly
30 seconds under a tap restores full airflow — the single biggest maintenance win.
If the dehumidifier still isn't working
Warning
Check the room temperature
Compressor dehumidifiers struggle below 15°C — the coils frost up and extraction slows to a trickle. For garages, conservatories and unheated spaces, use a desiccant model instead. Desiccant vs compressor guide →
Tip
Undersized is the number one problem
A 6L unit in a 3-bed house will never keep up, no matter how well you use it. Match the machine to the space: sizing guide →
Frequently asked questions
Bundle
The Effective Dehumidifier Setup — Approx. £120
- Devola 12L Dehumidifier£95Amazon →
- ThermoPro hygrometer£10Amazon →
- Smart plug with energy monitor£15Amazon →