Do You Need a Dehumidifier?

Signs you do: condensation on windows, musty smells, visible mould or mildew, damp walls or floors, excess moisture in bathrooms or basements that does not clear with ventilation. Ideal indoor humidity is 40–60% — above 60% encourages mould growth and dust mites.

Choosing the Right Capacity

Dehumidifier capacity is rated in litres per day — how much moisture they can remove. Match to your room size and humidity level.

  • Small room (up to 25m², slightly damp): 10–16 litres/day
  • Medium room (25–50m²): 16–25 litres/day
  • Large space or very damp conditions: 25–50+ litres/day
  • Whole house or basement: 40–70 litres/day
Bigger is usually betterA dehumidifier running at partial capacity uses less energy and cycles less frequently than a smaller unit running continuously at maximum. Buying slightly larger than you think you need is worth it.

Key Features to Look For

  1. 1

    Built-in humidistat

    A humidistat automatically turns the unit on and off to maintain your target humidity level. Without one, you have to monitor and switch manually. This is the most important feature for efficient operation — do not buy without it.

  2. 2

    Tank size and continuous drain option

    Water collects in a tank that must be emptied regularly — smaller tanks need emptying more often. Look for a continuous drain option (a hose connection that drains directly to a sink or outside) for basements or heavy-use situations where you do not want to empty manually.

  3. 3

    Noise level

    Dehumidifiers range from about 38–55 decibels. For bedrooms, look for models under 45dB. For utility rooms and basements, noise is less critical. Compressor-based models are noisier than desiccant models.

  4. 4

    Energy rating

    Dehumidifiers run for extended periods — energy efficiency matters. Check the energy star rating. More efficient models cost more upfront but save money over years of operation.

  5. 5

    Compressor vs desiccant

    Compressor models (most common) work best above 15°C and are more energy efficient in warm conditions. Desiccant models work better in cooler temperatures (garages, unheated basements in winter) and are quieter but use more energy. For a heated living space, compressor is usually the right choice.

Recommended Placement

Place in the centre of the room for best air circulation. Keep doors and windows closed while running. Empty or drain the tank before it fills — a full tank stops the unit. Clean the filter monthly.

Frequently Asked Questions

In the most problematic area first — typically a bathroom, basement, laundry or bedroom showing signs of damp. For whole-home use, place in a central location with doors open. On lower floors rather than upper floors, as moisture rises. Ensure at least 30cm clearance around the unit for air circulation.
For a moderately damp room, expect 24–48 hours of continuous running to bring humidity down to comfortable levels. Very damp spaces (after a flood or leak) may take several days. Once target humidity is reached, the unit cycles on and off automatically to maintain it.