Dehumidifier Buying Guide for UK Homes

A dehumidifier pulls moisture out of the air and can meaningfully reduce condensation and the mould that follows it, particularly in homes where ventilation alone isn’t enough — drying rooms, poorly ventilated bathrooms, or homes where opening windows isn’t practical.

What a dehumidifier won’t fix

It manages symptoms, not causes. If your damp is rising damp or penetrating damp, a dehumidifier will do very little — those need the underlying defect fixed (see our guide to telling damp types apart if you’re not sure which you have). It’s specifically a condensation-management tool.

Compressor vs desiccant

• Compressor (refrigerant) dehumidifiers work best in warmer rooms (above around 15–18°C) and are generally more energy-efficient for everyday use in a heated home.
• Desiccant dehumidifiers work well even in cold, unheated spaces like garages or lofts, run quieter in some models, but tend to use more electricity for the same moisture removal in a warm room.

Sizing

Dehumidifiers are usually rated by litres of moisture removed per day, tested under specific lab conditions that don’t always reflect real-world performance. As a rough guide, a small single room needs a smaller-capacity unit than an open-plan space or a whole flat being run continuously — check reviews for real-world performance in a room size similar to yours rather than relying on the rated capacity alone.

Running costs

Dehumidifiers draw a meaningful amount of electricity, especially compressor units run for long periods. Running one constantly in a large space adds up on an energy bill — it’s worth weighing that against fixing the ventilation or insulation issue causing the condensation in the first place, which has no ongoing running cost.

Practical tips

• Empty the water tank regularly, or plumb into a drain if the model supports it and you’re using it continuously.
• Keep doors closed in the room you’re dehumidifying so you’re not trying to dry the whole house through one unit.
• Use it alongside ventilation and heating habits, not instead of them.