What size Dehumidifier do you need?

Welcome to the complete guide to explain to you just exactly which size dehumidifier you need.

ecoair dc12 dehumidifier

Everyone’s set of circumstances is difference, therefore you shouldn’t assume that a particular size or power of dehumidifier will be sufficient in your home.

Firstly, it is important to actually talk about size and what we mean by this:

What do you mean by size?

When we are talking about what size Dehumidifier you need, we actually mean what capacity and power is required and how many litres of water per day the Dehumidifier will extract.

Certain room sizes, environments and types of house naturally require a more or less powerful dehumidifier than others, this is the question we are going to answer.

Dehumidifier Size Calculator Table

Conditions45 Meters90 Meters135 Meters170 Meters
Wet8.5L Per
13L Per
16.5L Per
20L Per
Severe Damp7.5L Per
11.5L Per
14L Per
17L Per
Moderate Damp6.5L Per Day9.5L Per Day12L Per Day14.5L Per Day
Mild Dampness5.5L Per Day8L Per Day9.5L Per Day12L Per Day

The above table will give you an indication of the kind of extraction power required from your Dehumidifier.
To give further clarification on what each of these rows and columns means, here is a breakdown:

  • Size of Room – Along the top it says 45 Meters, 90 Meters etc. This is the size of the room in cubic square meters. E.g. you measure your bedroom width, length and height then multiply together. 8M x 4M x 3M would be 96 Meters so the closest match is the second column.
  • Wet Conditions – This is a room that has a leak, water seepage or severe dampness on the walls. An example would be an old house with a cellar and your cellar regularly has water penetrate into it through the floor or walls or a room that has significant mould on the walls and are actually wet to the touch.
  • Severe Damp Conditions – Generally always feels damp and musty in the room. You may have damp patches on the walls from penetrating damp or condensation forming on the walls. Condensation appears on your windows, especially when it is colder.
  • Moderate Damp Conditions – You have slight condensation that forms on the windows in cooler weather. You sometimes feel the room feels musty or damp, but not all the time. A bedroom feeling musty and damp after you have had 8 hours sleep.
  • Mild Damp Conditions – No major dampness on the walls, very rare condensation. You wish to dry your clothes washing inside your house without the use of a Tumble Dryer – You need a Dehumidifier to prevent the moisture from escaping into the room with no where to leave.

Now you have seen the table above and established the conditions you are in, you know what kind of litre removal abilities you require from your Dehumidifier.

Scenarios whereby the wrong size is being used

The Unibond Aero 360 is quite a popular “Dehumidifier” despite it not having any electrical components. Sometimes people will experience damp issues in a room within an old house and then purchase one of these to combat the problem.

Not suitable for a damp house or large room!

The problem is, this is simply not enough! A normal low end Dehumidifier would extract hundreds if not thousands of times more water than the Unbond Aero 360 in the time it took for it to fill up.

Another scenario would be having a very small house with a small damp room and buying the all singing, all dancing Dehumidifier – this is not necessary as your room isn’t big enough to require it.

This really is one of those circumstances where if you have a large or severely damp room, you need a more expensive, larger and more powerful dehumidifier.
If you have a smaller, more mildly damp room, you will only require the less expensive, smaller and less powerful dehumidifier.

Examples of Dehumidifiers

We have an in-depth article on the Best Dehumidifiers on our home page, but to help you in deciding which size dehumidifier you need, the information we provide includes the extraction capabilities of the Dehumidifier too.