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How Much Does it Cost to Run a Dehumidifier?

We’re often asked how much does it cost to run a dehumidifier. In this article, we’re going to discuss the basic costs of operating one, as well as the factors that can influence them.

The Short Answer

The cost of running a dehumidifier can vary depending on the energy rating of the dehumidifier, your energy tariff, and the number of hours that it is running.

The estimates below are using the average energy tariff of the average rate of 18.54p/kW in December 2019.

Power Rating Per Hour Per Day* Per Week
100W 0.1kW £0.02 0.10kWh £0.22 1.20kWh £1.56 8.40kWh
250W 0.25kW £0.05 0.25kWh £0.56 3.00kWh £3.89 21.00kWh
500W 0.5kW £0.09 0.50kWh £1.11 6.00kWh £7.79 42.00kWh
750W 0.75kW £0.14 0.75kWh £1.67 9.00kWh £11.68 63.00kWh
1000W 1kW £0.19 1.00kWh £2.22 12.00kWh £15.57 84.00kWh
1500W 1.5kW £0.28 1.50kWh £3.34 18.00kWh £23.36 126.00kWh

*data from sust-it.net and based on 12 hours a day using the Average rate of 18.54p/kWh (December 2019 tariff) for a unit of electricity.

How long do dehumidifiers need to run?

The number of hours a dehumidifier is on is an essential factor in cost. Many people believe that dehumidifiers should run for 24 hours a day, which as you can imagine, can be quite expensive.

Unless your home happens to have high levels of humidity or damp, then this is considered to be a waste of electricity. Many good quality dehumidifiers can extract a fair amount of moisture in around a six-hour period.

If you’re worried about the running cost of a dehumidifier, you should look at purchasing an energy-efficient dehumidifier, or a type that uses less power to run, which we will discuss next.

Basic dehumidifier cost calculation

Once that you have found a unit you like, and you can see how much electricity it uses, you can also calculate how much the unit will cost over a specified period.

To do this, you will first need to discover the wattage of the unit. Once you find out what it is, take the wattage and multiply it by the hours you intend to use it and divide it by 1,000.

By doing this, you will have found the kWh measure.

So for example:

(400 watts x 10(hours per day) x 365(days per year)) divided by 1,000

=1460kWh x 7 pence(kWh)

=£102.2/per year

Of course, this can only be a rough estimate of how much a dehumidifier will cost to run, as already explained, there is a range of reasons and factors that come into play.

For example, a very efficient unit that uses more power to remove humidity than a less efficient unit that runs on less power can still be more cost-effective — even if it runs for a more extended amount of time.

Overall, it is thought that the running cost of a typical dehumidifier, depending on the humidity and the size of the area, would be around £10 to £20 per month.

That said, a recent study showed that the average home dehumidifier uses 4.2kWh per day, while direct drain units use 5.6kWh per day, and manually emptied dehumidifiers use 3.7kWh per day.

This calculates to an annual operating cost of around £80 or so per year, which is approximately 9% of the average electricity consumption in a typical home.

Other studies, however, have shown that dehumidifiers can cost up to £25 per month when they are used for extended periods of time.

It’s also worth noting that researchers tend to classify dehumidifiers as “energy-intensive appliances” in domestic settings.

How can you lower dehumidifier costs?

Which dehumidifiers are energy efficient?

The first thing that you should consider when trying to reduce cost is whether the unit you’re purchasing is made with a compressor or desiccant system. This is because compressor dehumidifiers are more cost-effective to run, as desiccant systems use hot air to extract water from the desiccant material.

As a result, desiccant systems use much more energy to do the same job effectively. Depending on the quality, make, and model, a desiccant dehumidifier can use as much as 50% less power.

Saving through lowering the thermostat

Lowering thermostat to save energy

Lower the thermostat to save energy

One of the many benefits of running a dehumidifier in your home is that it will feel warmer.

This is because of the reduced humidity (moisture) in the air, as on a chilly day, condensation can take the heat energy away from our bodies through evaporative cooling.

What’s more, the insulating layers of air trapped between our skin and our clothes are more difficult to heat when more humidity is present.

Once that your home feels warmer due to the addition of a dehumidifier, it is possible to turn the thermostat down without feeling any heat loss.

In fact, by turning your temperature down just one degree, you could look to save between one and three percent of your annual heating bill.

Saving on the bills directly

There’s also a bit of science that is worth considering.

As the heat capacity of water is four times greater than air, it means that water takes over four times the energy to heat. So, at just 20˚C (68˚F) a 35 cubic foot of air can hold 0.63 ounces of water. In this instance, the relative humidity would be recorded at 100%.

At 45% humidity, therefore, which is considered ideal, 35 cubic foot of air would hold just 0.28 ounces of water, which means it would be much easier to heat.

So if a four-bedroom house contained approximately 35,000 cubic metres of air at a humidity of 75%, the house would hold an extra 11.9lbs of water in the air. It would take around 0.0063kWh to heat this excess moisture by one degree.

If the heating came on twice per day and needed to heat the home by just two degrees, then this would equate to an extra usage of 9kWh per year, which depending on your electric company, could cost around £3-£5 pounds.

Save on drafts and mold damage

Man checking ventilation

Check ventilation to reduce costs

We all know that poor ventilation can cause a series of issues in your home, including mold, damp, and of course, condensation.

A dehumidifier combats all these issues and owning one, in the long run, means that you won’t have to worry about ventilation and all the tactics that you previously used to encourage it.

A downside of leaving windows and ventilation flaps open is that they can cause draft issues, which means that your home is less energy-efficient and will in effect cause your bills to be more expensive.

In fact, by merely blocking drafts, you could look to save between 5% and 30% on your heating bills each year.

Due to the fact that the average heating bill in a home using gas is just under £600 per year, this means that if you save only 5% on your bills, you could look to save around £30.

What’s more, damage to walls, windows, and soft furnishings by mold and condensation could cost hundreds of pounds if left untreated.

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