Which type of dehumidifier in 2024

Understanding Condensing/Refrigerant Dehumidifiers

Condensing dehumidifiers operate by creating a cold surface that attracts moisture from the air. This process uses a refrigeration circuit like that in fridges or AC units. Here's how it works:

Air is drawn in by a fan and directed to a cold coil evaporator.
The air's temperature drops below the dew point, causing moisture to condense on the coil.
Condensed water drips into a drain or water tank.
The cooled air is then warmed by the condenser before being released back into the room, now drier and slightly warmer.

Understanding Desiccant Dehumidifiers

Desiccant dehumidifiers utilize a rotating desiccant wheel to absorb moisture directly from the air. Here's the detailed process:

Air passes through the revolving desiccant wheel, which acts like a sponge.
The desiccant absorbs the moisture, and the dried air is returned to the room.
The wheel moves through a regeneration area where it is heated by a secondary hot airstream, often using an electric heater.
The hot airstream (around 120°C) removes moisture from the desiccant, which is then vented outside.
The regenerated wheel, now carrying residual heat, returns to the process airstream, adding warmth as it dries the air.

Key Differences and Usage

Condensing Dehumidifiers: Suitable for warmer environments, where they efficiently condense moisture. Ideal for general home use, swimming pools, basements, and other indoor areas.

Desiccant Dehumidifiers: Effective in lower temperatures and can provide additional heating. Best for colder environments and applications where temperature control is critical, like warehouses or construction sites.

What size of dehumidifier do you need?

It depends on the specific problem areas and their sizes.
For preventing mould in smaller rooms (under 400 square feet), a dehumidifier with an extraction rate of 10 to 14 litres per day should be sufficient.
For larger rooms between 400 and 800 square feet, such as living rooms or bedrooms, you'll need a more powerful dehumidifier. One that extracts around 20 to 25 litres per day should be effective.