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 on a dehumidifier will allow them to control when the unit turns on each day and this will be the best way to use their dehumidifier – but that is a myth.
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. It is the humidistat, coupled with the setting that you have selected, that decides whether the dehumidifier needs to work or not.
If you restrict the dehumidifier by having it turned off for several hours per day then the humidistat will not be able to do its job. So the unit will not spot that you have had a bath or a shower, or cooked a meal - 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 such as your wardrobe, clothes, sofa and plaster.
This is exactly what you do not want to happen - and presumably the reason why you bought the dehumidifier in the first place was to stop this sort of thing from happening.
Let the dehumidifier decide
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 want to use the timer on a dehumidifier to restrict the hours that the dehumidifier runs is because they are worried about the running costs. This is unnecessary. In the UK, dehumidifiers are mostly used 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.
By removing moisture from the air, the dehumidifier is helping to reduce your overall energy bills. That's because there will be less moisture in the air and therefore less work for the heating system to do.
So why is there a timer on a dehumidifier unit?
Good question! The timer is mainly useful for drying washing at minimal cost. Dehumidifiers are great at drying washing. Just 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 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!