While most people will appreciate that de-humidifiers reduce humidity relatively few will know that they are also very efficient heaters.
Measured in real life experiments consumer de-humidifiers have a heat gain of 2 – or more formally CoP of 2.

In lay terms that means for 1Kw of electricity in the de-humidifier gives out 2Kw of heat – so runs at half the cost of an electric heater or radiator.

Using a de-humidifier to generate heat can save about £25-40 per month in a typical house.

One may question how this happens. It’s actually quite simple. When you boil a pan and leave it boiling you need to add energy to make the water evaporate. A de-humidifier reverses this by condensing water – releasing about 1Kw of energy for each 1.65 litres of water extracted. This is known as the latent heat of condensation

The latent heat of condensation for water is approximately 2.26×1062.26×106 J/kg or J/L. This translates to 0.627 kWh for every litre of water condensed.

To delve into this, we’ll take a closer look at the Meaco Arete Dehumidifier 25L as a case study.

This experiment was done in a typical two bed flat with the humidistat set to 55%.

• Power was measured using a plug based power meter – in kWH
• The water extracted was weighed to calculate the latent heat of condensation

Meaco Arete Dehumidifier 25L: This dehumidifier consumed 1 kWh of electricity in our test scenario and was able to extract 1.65kg (or 1.65L) of water from the environment.

From the water it condensed: Heat energy from condensation=1.65×0.627kWh=1.03kWh

Taking into account the energy it consumed, which also contributes to heating the environment: Total heat produced by the dehumidifier=1kWh (from electricity)+1.03kWh (from condensation)=2.03kWhTotal heat produced by the dehumidif

Thus, for every 1 kWh of electricity consumed, the Meaco Arete Dehumidifier 25L releases a combined heat of 2.03 kWh from both its electrical operation and the condensation process.

In contrast, a standard electric heater, for every 1 kWh of electricity consumed, produces a straightforward 1 kWh of heat.