This is the most common question that we are getting at the moment. Phone call after phone call telling us that their dehumidifier never seems to turn off and it is collecting lots and lots of water. Is this normal people ask us?
The answer is yes.
The Explanation – Why it’s normal.
The dehumidifiers have a built in humidistat that measures the temperature and relative humidity of the room and tells the dehumidifier whether to sleep or dehumidify. If you have a house that has never had a dehumidifier in it before then the dehumidifier will be running flat out for around two to four weeks while it dries out all of the air in the house and then the organic material in the house (wood, clothing, furniture, paper, books etc.) releases all of the moisture into the air that they have been holding on to, giving the dehumidifier more work to do.
As well as the above you are also putting moisture into the air each day (bathing, showering, cooking, breathing etc.) and this slows down the process of getting to a point whereby the humidity is low enough for the dehumidifier to turn off for a rest.
Then there is the weather, if it is raining a lot then the dehumidifier will run for longer. When it has caught up and brought things under control you will find that your dehumidifier turns off and then you will settle into a cycle of on/off/on/off as required.
After all you bought the dehumidifier to dry your house and that is exactly what it is doing for you. So don’t be too hard on your poor old dehumidifier!
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240 responses
Thanks for replying. That does help ease my mind. Thankyou. Also the defrost setting comes on quite often but I wouldn’t say my house was especially cold. And would you recommend the high or low setting?
Susan,
Just ignore the defrost, as long as the machine is collecting water then all is fine. Dehumidifiers have to defrost internally from room temperatures of about 18°C.
High setting will extract more water and low setting is useful when you want to reduce the noise level.
Chris
I recently purchased a Meacodry ABC 12l dehumidifier. I have never owned one before and am feeling somewhat confused. It never switches off. I keep reading about warm air being expelled but I wouldn’t call the air coming from this one warm. Is this size large enough for a 3bed house. Should I have the setting in high of low. The fact that it is running constantly makes me feel concerned about the electricity bill.
Susan,
Thank you for your purchase. As this is a low energy dehumidifier heat is not generated by the process because where there is heat there is cost. The air coming out is around 1C-2C warmer than the air that went into the dehumidifier. You will find that the dehumidifier will work hard whilst it dries the house out, this will take a month or so, after that it will slow down.
The running costs are similar to leaving a few light bulbs on.
Hope this helps.
Chris
Hi Chris. Similar to others. I bought a DD8L yesterday. Set on one fan and thumbs up it started and blows out warm air. After about 4 hours the air flow changed to cool. Stayed cool for 45 mins until I turned up the setting to laundry then warm air came out. Back on thumbs its still running warm. Has gone cool again occasionally but not turned off. Help
Paul,
Thank you for your purchase. What you describe is not a fault and is just part of the normal running of the machine. Just let it do it’s own thing. If it has a fault then the warning light will come on.
Chris
I have mound growing on my clothes and furniture in the lower ground of my house. One side of the building is underground. There is a musty stench in the rooms. Would a dehumidifier help.? It feels cold down there too. What would you recommend and why is this happening
Siobhan,
A dehumidifier will defintely help and the Meaco 20L or Meaco 25L would be best.
Chris
Hi, I have a meaco 12l low energy dehumidifier. I have set the %humidity to 50%, however even when the reading is around 43% the dehumidifier is not turning off as it should do. Do you know why?
can you confirm if this is the reading on the dehumidifier or a third party device please? Feel free to call the office on 01483 234900 if that is easier for you or email us via service AT meaco.com
Thank you for replying. If I persist with what I am doing, is this something that will resolve?
Depends on where the water is coming from, we once had a client who has a burst pipe outside from a garden fountain and the problem did not stop until that was resolved. Another client had a garden that sloped down to the house so all rainwater just kept on coming down into the house. Problems like that cause battles that a dehumidifier will never win.
In your house I would try and keep doors and windows closed for longer whilst the weather is mild (in winter it can help, please read the two ventilation articles from 24th Feb 2015 – https://www.meaco.com/blog/?s=ventilation), opening when it turns cold could help.
Leave any internal doors open and just have the one or two dehumidifiers running in the one spot 24/7. Keep emptying them and see where you are in 8 weeks time.
We have house 1840 period. Stone walls. Regularly get mouldy wooden furniture. We do not place anything close to walls so there’s plenty of circulation room
We bought hydrometers for each room to try and deal with issue. One room downstairs can be closed off but the rest of downstairs is openplan. All Windows are opened every morning for an hour and backdoor is open pretty well all day
We have three dehumidifiers and move them round the house all day. They run approx 12 hours each and electric bill is huge
We have been running them for four weeks (when doors and Windows closed) and get below 60 in few hours. My question is, as soon as dehumidifier is off the humidity levels in all rooms moves to 69/70 really quickly. Every morning all through the house is 80.
I can run to 54 but it still rises quickly as soon as I move machine to another room
I’ve even tried leaving one on the landing. One in hall and one in open plan area and this can lower levels all through to around 65
Am I doing right? So frustrated
Pat,
This is because the walls are acting like a sponge and releasing moisture into the house as soon as the dehumidifiers have dried the space. Having doors and windows open will also attract lots of extra moisture in from outside as the damp air from outside is attracted to the dry space inside.
Chris
Our dehumidifier runs constantly, but doesn’t fill the reservoir that often. Is there a way to determine whether the unit is low on refrigerant?
James,
When a machine is low on gas you will start to see excessive amounts of frost build up on the coils behind the filter, usually in the bottom third only.
Chris
Hi Chris,
This is a great article. But I still feel that there’s something wrong with my humidifier.
I’m from Lisbon, Portugal. The RH here this time of year is around 60-70%. The temperature is around 80F. If you could give me some advice, it would help me a lot.
I was having lots of mold on walls and on an old wooden wardbore in my room, so I’ve decided to get a dehumidifier.
My room is 10m² (100 square feet) in area. I got a Becken 20liter (42 pint) and it’s been running for 72 hous non-stop now. I get that the room might be releasing some extra moisture but something is not adding up to me.
I’ve noticed that it’s running on the following cycle: 15 to 18min with compressor on, then around 3 minutes with fan only (compressor off), then it shuts off completely for 20 seconds, and it restarts with full compressor and fan to cycle again. And it does that kind of cycle even during the day, when there’s no one inside the room.
I’m setting it to 50%. It reaches that level on the first 5-10 minutes with the compressor on. Then it remains at 50% until the compressor turns off. And then, during the 3 minutes with fan only, the humidity goes to 52%. Then, during the 20 seconds of full shut off (without fan) I can see it going back to 53, 54 and 55%. At 55%, the compressor gets triggered again and the cycle restarts.
It’s collecting aproximately 3 liters of water / 24 hours running. Which I think is too little, for a room that is in theory building up from 50 to 55% humidity in a matter of 3 and a half minutes. What do you think? Thanks a lot.
It’s collecting around 3 liters of water every 24 hour, which I’m guessing.
Caue,
It sounds like you have a dehumidifier that does not benefit from a nice control logic and the dehumidifier is struggling when it is turned off with differentiating between room humidity and it’s own internal relative humidity hence the readings bouncing around and the machine turning on and off on a regular basis. That explains it’s behaviour. Rooms can take several weeks to dry out so I am afraid you will have to be patient on that one.
Chris
Had to run a de-humidifier ever since we bought our house new 15 years ago. Between Spring and Fall we run it constantly even in dryer weather the humidity will rise above 60% so the de-humidifier keeps it at 50% or so. In our area the sub level ground in moist and seeps moisture through concrete to a point where if you did not de humidify you would be dealing with mold and mildew. You can chase after this seepage by sealing the concrete and applying a vapor barrier outside on basement walls which can help. But that’s costly and you still may need a de-humidifier.