The Biggest Dehumidifier is the Greenest Dehumidifier?

by Tom Warren (Preston, UK)

If you have tried everything else to solve a moisture problem in your home you may consider buying a dehumidifier. You are a responsible person and you want to take care of the environment. Which type of dehumidifier is kindest to the planet?Dehumidifiers come in different sizes; portable home dehumidifiers in the USA, for example, range from 25 to 74 US pints (12L-35L) per day and commercial quality units from around 50 to 150 pints (24L-70L).Smaller dehumidifiers use less energy don’t they??Yes.So, a smaller dehumidifier causes less damage to the environment, right??No, its not quite that simple.Larger dehumidifiers are more energy efficient than smaller models. The best way to explain this is using the Energy Factor (EF) concept applied by the US Energy Star Program when certifying dehumidifiers as “energy efficient”. The EF is a measure of the volume of water (litres) removed by a dehumidifier for every energy unit (kilowatt hour) consumed.Because smaller dehumidifiers are always less efficient than larger ones the EF they must achieve for certification is lower. A 25 pint unit, for example must have an EF of at least 1.2 L/kwh whereas a 70 pint dehumidifier must achieve at least 1.8. Thus a 70 pint dehumidifier removes 50% more water per energy dollar

spent than a 25 pint unit.A dehumidifier is controlled by a humidistat; like a thermostat but for maintaining a pre-set level of humidity rather than temperature. The humidistat ensures that the dehumidifier only runs when the moisture content of the air is higher than the programmed level.The 70 pint dehumidifier uses more energy while its running but runs for a much shorter time to reduce humidity, using less energy overall. Therefore the carbon emissions caused by generating the energy used to run the larger dehumidifier are less than those caused by the smaller unit.This is good for the environment and good for your pocket as energy costs over the life time of a dehumidifier are far greater than its initial purchase price.What is more, because a 70 pint dehumidifier runs for fewer hours per day than a 25 pint unit it will last longer. That means you need fewer replacements over your life time, reducing the environmental damage caused by manufacturing dehumidifiers and saving even more of your money.So, although it seems to deny common sense, the greenest dehumidifier is the biggest dehumidifier. It’s also the best dehumidifier if you want to save money, which can’t be bad for anyone.


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