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Calculating the capacity of the dehumidifier you need for your basement involves considering several factors, including the size of the space, the level of dampness, and the conditions that contribute to the humidity. Here's a step-by-step guide to help you choosing the right dehumidifier.

1. Measure the Area:

  • Square Metres: Measure the length and width of the basement and multiply them to get the area in square metres (m²).

  • Cubic Metres: For a more accurate calculation, also measure the height of the basement and multiply length × width × height to get the volume in cubic metres (m³).

2. Assess the Dampness Level:

  • Moderately Damp: If the basement occasionally feels damp and has a musty odour in humid weather.

  • Very Damp: If the space always feels damp and moist, and the odour is persistent.

  • Wet: If there are visible signs of moisture, like water stains, and the space feels wet.

  • Extremely Wet or Wet Year-Round: If there is standing water or the basement is subject to flooding.

3. Refer to Dehumidifier Capacity Charts:

Dehumidifier capacity is measured in litres of water removed per day. Refer to capacity charts provided by manufacturers, which typically recommend capacities based on the square metres and dampness level of the space.

Example Chart:

Moderately Damp:

  • 46 m²: 4.7 litres

  • 93 m²: 6.6 litres

  • 139 m²: 8.5 litres

Very Damp:

  • 46 m²: 5.7 litres

  • 93 m²: 8 litres

  • 139 m²: 10.4 litres


  • 46 m²: 6.6 litres

  • 93 m²: 9.5 litres

  • 139 m²: 12.3 litres

Extremely Wet:

  • 46 m²: 7.6 litres

  • 93 m²: 10.9 litres

  • 139 m²: 14.2 litres

4. Consider Additional Factors:

  • Temperature: If the basement is cooler, consider a dehumidifier designed for lower temperatures.

  • Airflow: Assess the airflow within the basement, as stagnant air can impact the dehumidifier’s efficiency.

  • Location: If the basement is divided or has multiple rooms, consider a dehumidifier with higher capacity or using multiple units.

5. Add a Buffer:

  • To ensure effectiveness, it’s prudent to purchase a dehumidifier with a slightly higher capacity than calculated. This also allows the unit to operate more efficiently and with less strain.

6. Energy Efficiency:

  • Finally, consider the energy efficiency of the dehumidifier, as more efficient units can save on energy costs in the long run.

By taking the time to assess your specific needs and referring to the guidelines above, it will be easier choosing the right dehumidifier with the appropriate capacity to effectively manage the moisture levels in your basement.

Here are some links for reliable dehumidifiers.


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