Dehumidifier running cost

The Running Cost of a Dehumidifier can depend largely on two crucial factors, namely the actual energy rating of the Dehumidifier and the number of hours in which the Dehumidifier is actually operating.

Suffice to say that Dehumidifiers have become more popular in households over the years, probably as a result of the increase in rental properties, which usually tend to be poorly heated, and ventilated and the widespread use of double glazing which limits natural room ventilation, causing moist air to get trapped in rooms, increasing humidity to a level which causes condensation to form on cold surfaces such as outside walls.

This has been further complicated by the increase in drying washing indoors, due to escalating energy costs. Drying washing on radiators and clothes airers can result in several litres of moisture evaporating into plaster and the building fabric, eventually resulting in damp and possibly black mould issues. If you dry washing indoors without ventilation, then a dehumidifier with a drying laundry function should be at the top of your list.

Dehumidifiers will not, by themselves, completely substitute the requirement for a heating system, they can be a perfect partner to any existing heating system, as damp and levels of high humidity can often cause even a warm room to feel much colder than it is, and also require more energy input from any domestic heating system in order to combat the effects of damp, humid air and so the use of a dehumidifier can effectively reduce heating costs. The energy rating of most Dehumidifiers is measured in watts, and often the wattage figure is far less than an average sized electric heater, however Dehumidifiers are designed to be left running for much longer periods in order to maximise their effect.

Many people believe that they should leave their Dehumidifiers running 24 hours a day, which can work out quite expensive. Most good quality modern Dehumidifiers are very efficient and choosing a model with a built in humidistat will result in the unit only switching on when humidity levels reach problematic levels.

There are two types of De-humidifier available. The most common type uses a rotary compressor, to cool metal coils which then draw the trapped moisture out of the air, these tend to be very noisy in operation and are slower at starting to remove moisture, however they do have the lowest electricity consumption of the two types.

The newer type of dehumidifier is called a Desiccant De-humidifier these are virtually silent and also much more effective in removing moisture compared to conventional dehumidifiers, however they also consume more power, around two to three more times Electricity than compressor types, but using a Desiccant De-humidifier for a few hours can also raise the room temperature by as much as 7c to 12c in a well insulated room which is often enough to reduce the demand on your main heating, thus effectively paying for its own use through a commensurate reduction in heating bills.

Desiccant Dehumidifiers also have the ability to dry laundry much quicker than room airing alone, whilst preventing damp and condensation.

Desiccant Dehumidifiers are also more effective than compressor types when working at lower ambient temperatures, and so are more suitable for use in porches, conservatories, outhouses, cellars and conservatories or poorly insulated homes and flats. Older buildings especially, will benefit from the use of a desiccant based appliance.

I have listed below the hourly running cost of the most popular Desiccant Dehumidifier – Meaco DD8L. All running cost have been calculated using an example figure of 30p per KW/H as an Electricity cost (Which is the average UK electricity kw/h cost – updated as of Oct 2023)

Meaco DD8L – Low (330 watts) – 10p per hour / High (650 watts) – 19.5p per hour

Don’t forget that the Meaco DD8L has a built in humidistat which means once the humidity has been reduced to the desired level, the unit will only operate when the humidity levels increase and so it won’t be consuming power continuously.

If your model of dehumidifier is not the one above, you can work out the cost of running it yourself by using the following formula.

(1000 watts = 1kw and so 250 watts would equal 0.25kw)

So you would work out your dehumidifier running cost by using the following equation:-

KW X Electricity cost in pence X number of hours run

So a 150 watt dehumidifier running for 12 hours with an Electricity cost of 30p per unit can be worked out as:-

0.15(kw) x 12 (hours) x 0.30 (kwh cost) = 54 = 54 pence

1 Response to Dehumidifier running cost

  1. simon says:

    a factor that is normally missed in these cost calculations is that every litre of water that is condensed releases 0.6kWh of heat energy ( latent heat of vaporisation).

    If the air is very damp this will be easier for the dehumidifier to extract (i.e. cheaper) and the use of a dehumidifier is very cost effective.

    In addition to this it appears that damp plaster is a much better conductor of heat than when it is dry further improving the efficiency of using dehumidifiers.

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