Dehumidifiers are wonderful pieces of equipment that improve our quality of life. Most of us are guilty of turning ours on and walking away; safe in the knowledge that it will continue to draw unwanted moisture and humidity from the air.

It is only when we come to empty the collection tank or notice that the air seems unusually thick and sticky, that we think to check if the machine is working.

Even if the power light is on and you can hear the motor running, how do you know if your dehumidifier is working efficiently?

There are several methods to check if your dehumidifier is working, the most reliable one is using a hygrometer.

They are small sensors that give accurate readings of room temperature and humidity levels. Hygrometers are inexpensive and readily available.

Set the humidistat at the appropriate level; usually, we recommend around 35% relative humidity. After the dehumidifier has run for around an hour, check the reading on the hygrometer. If the unit is functioning the display should tally with the setting.

If the two settings are different; your dehumidifier isn’t working as it should.

Things that cause a dehumidifier to stop working

Blocked filter – Dust mites and dirt that collect on the filter prevent it from functioning. It results in a change to the water level, creating an atmosphere that is more humid or drier than required.

Cleaning or replacing the filter should rectify the issue.

Motor problems – The system employs a fan to expel the clean air; you can feel it blow when up close to the dehumidifier.

If there is no air, the fan motor may have burnt out.

Call in a professional to replace the motor, to prevent it from reoccurring, clean the fan each time you empty the tank.

Frost on the coils – At the rear of the dehumidifier is an evaporator, similar to that of a fridge. Comprised of a system of coils, if the moisture in the air becomes too cold, the condensation freezes on them.

Heat the room and let the unit defrost slowly. If this doesn’t work, it is probably time to invest in a new machine as coils are expensive to replace.

Broken sensor/switch – A sensor inside the drainage system of a dehumidifier automatically cuts the power when it senses a full collection tank.

If the tank is only half full, adjust its position and reset the switch.

If the unit still doesn’t function, you will need to replace the sensor.

Final thoughts

To extend the life of a dehumidifier, change the filter annually, and keep it clean. It is important to wipe the fan and vents regularly to prevent dust build-up.

To find out if your dehumidifier is working properly, start by getting a cheap hygrometer.

Then, operate it at the manufacturer’s recommended setting and use it in room temperature above 16°c.

Follow all of these guidelines and you should have optimal air-quality for a long time, and avoid expensive repair costs along the way.