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Often when people are buying a dehumidifier for the first time one of the features that they look for is a timer.  They think that the timer will allow them to control when the dehumidifier turns on each day and this will be the best way to use their dehumidifier – they are wrong!

A dehumidifier has something called a humidistat that measures the relative humidity of the air (the amount of moisture in the air that could potentially cause condensation) and it is the humidistat, couple with the setting that you have selected, that decides whether the dehumidifier needs to work or not.  Now if you restrict the dehumidifier by having it turn off for several hours per day then the humidistat will not be able to do its job and the dehumidifier will not spot that you have had a bath or a shower, boiled vegetables and as a
consequence the relative humidity has increased.  This new moisture in your home will be free to do as it pleases and will move around the house until it is absorbed by organic materials, which is a posh way of saying your wardrobe, clothes, sofa and plaster will absorb the moisture. This is exactly what you do not want to happen and presumably the whole reason why you bought the dehumidifier in the first place was to stop this sort of thing from happening.

It is much wiser to let the humidistat make the decisions about the level of moisture in the air rather than try and guess yourself.

One of the reasons why people try and restrict the hours that the dehumidifier runs is because they are worried about the cost of running the dehumidifier.  This is unnecessary.  A dehumidifier is mostly used in Great Britain as a winter product, all of the energy it uses is returned to the room as heat and heat in winter is a good thing.  Secondly by removing moisture from the air the dehumidifier is helping to reduce your overall energy bills because there will be less moisture in the air and therefore less work for the heating system to do.  This is because the heating system has to heat every single water molecule in the air and if the dehumidifier has removed a whole load of them then there will be less work for the heating to do to make you warm.

People talk about a damp chill; this is because excess moisture in the air cools the air, by removing the excess moisture the dehumidifier is contributing towards a warmer home.

So what is the timer there for on a dehumidifier if you are meant to run them 24/7?  The timer is useful for drying washing at minimal cost.

Dehumidifiers are great at drying washing, pop them next to a clothes horse in a confined space and use the Laundry mode to dry the washing in a couple of hours.  The clothes will feel softer than they do when you use the tumble dryer because the dehumidifier does
not use heat to dry the clothes, just dry air.

Once you get used to how long it takes to dry your washing you can leave the timer on for say an hour or two and you can go off to work knowing that the dehumidifier will work at maximum capacity for a couple of hours and will then switch itself off.  Your washing will be dry when you get back in and the timer will have ensured that you have used as little energy as possible to dry that load.

That is what a timer is for!


Author: Chris Michael

Chris Michael has been in the humidity business since 1989 and founded Meaco in 1991. Much of his knowledge comes from the numerous years spent working with museums and art galleries across Europe controlling and measuring relative humidity to protect the works of art. He is a regular guest speaker on relative humidity at the British Library and is always happy to pass on his knowledge in a practical way to his customers. Outside of Meaco Chris is married with four children and is very active in the local community, especially through youth sport. Further thoughts can be found on Google+ and Twitter