Here at Meaco, we have great conversations with our customers all the time. We’re commonly asked questions about desiccant dehumidifiers, so we thought we’d put this handy guide together.
How Does A Desiccant Dehumidifier Work?
A desiccant based dehumidifier draws the air in from the room over a filter and passes it over a rotating wheel. This wheel is full of a material called Zeolite which absorbs the excess water out of the air. When the wheel is saturated it needs to be regenerated. A heater in the base of the dehumidifier blows warm, dry air over the Zeolite to force the moisture out of the wheel. The Zeolite is now ready to dry again and the warm, wet air from the wheel hits a metal surface which ensures the excess moisture condenses and the water drips into the internal tank. The heat used during the drying process is mixed with the dry air to ensure that the air that comes out of the dehumidifier is not just drier but 10-12°C warmer than the air that came in.
My Dehumidifier Has Stopped Collecting Water
Desiccant dehumidifiers like the Meaco DD8L and the Meaco DD8L Junior have a pre-set humidistat so in Minimum mode they dry down to 60%rh, in Normal they dry down to 50%rh and in Maximum they dry down to 40%rh. Once they reach that level they turn themselves off and then check the relative humidity once every 30 minutes to see if the relative humidity has increased.
I Have Laundry Out And No Water Is Being Collected
If the relative humidity is below 40%rh then the dehumidifier will not collect any water. The moisture from the washing will evaporate into the air and increase the moisture content of the air but this increase might not be enough to increase the relative humidity above 40%. This is a very common issue in winter when there are temperatures below freezing outside and we have our heating on in the house.
I Have Condensation On My Windows And Still No Water Is Being Collected
Condensation forms when a surface is at the appropriate cold temperature, so if you have a room temperature of say 20°C and a relative humidity of 35%rh then there is nothing more for the dehumidifier to do because the air is cold enough.
If the surface temperature of the windows drops to just under 5°C or colder overnight then you will get condensation. The dehumidifier is not to blame; it is all down to the quality of the glazing.
How Can I Be Sure If The Relative Humidity Has Dropped And The Machine Is Not Just Faulty?
After a bath or a shower, leave the window closed in the bathroom and put your desiccant dehumidifier in the bathroom in its Laundry mode. Shut the door the best you can and turn off the extractor fan, come back in two or three hours time. If water is collected then the machine is fine, if no water is collected then let us know as the dehumidifier is faulty and we need to sort it out for you.
A desiccant dehumidifier is a cost-effective way to manage condensation in your home.
How can I prolong the life of my machine and keep running costs down?
Keep the filter clean. The more dirt on the filter, the more strain on the fan and the greater the risk of the fan or the heater failing. This will also prevent the dehumidifier from become nosier than necessary.
Does running a desiccant dehumidifier cost a lot of money?
Desiccant dehumidifiers are very energy efficient – all energy that is consumed returned to the room as heat. This is a good thing as it replaces the heat generated by your central heating. Desiccant dehumidifiers also dry the air very quickly, so they are in dehumidification mode for much less time than compressor based dehumidifiers. Southampton University tests show that this is around 3.5 times faster. This means that they can actually be cheaper to run than compressor dehumidifiers.
Remember that whatever dehumidifier you use, you are reducing your heating bill by making the air dryer. Dry air is much easier to heat than damp air because there are fewer water molecules in the air. The money you save on the heating bill will outweigh the money that you spend on the dehumidifier.
In fact the best way to waste money is to not run the dehumidifier and let the level of moisture build back up in the house!
The air feels cold coming out of the desiccant dehumidifier
It might but it is not! When the desiccant dehumidifier is drying, the air coming out is 10-12C warmer than the air that came in. This is because the energy used in drying is being returned to the room. When the dehumidifier stops drying and goes into fan only mode to sample the air it does nothing to the air, the air just passes through the machine, nothing more. When it comes out it is exactly the same temperature as when it came in, nothing has happened to it. Moving air feels cooler than still air (like a fan in summer), but it is not cooler and the room temperature will not drop.
How does damp air affect my health?
We are keen to steer clear of claims here that we are not qualified to make, so we will keep it simple.
- Dust mites reproduce in damp environments
- People who suffer from asthma, eczema and other allergies find that inhaling dust mite droppings can make their condition worse.
- Mould grows in damp environments.
- Mould gives off mould spores (seeds)
- Inhaling these spores can make conditions worse.
A dehumidifier keeps conditions dry and therefore stops dust mites from reproducing and mould from growing. Therefore a dehumidifier helps people who suffer from allergies, asthma and eczema.
Find out more about dust mites here.
Does the desiccant need to be changed?
No the machine automatically regenerates the desiccant internally and you will never have to replace it.
Are there are replaceable parts?
No
What about the filter?
Just maintain the filter as per the manual and it will be good for the life of the machine.
My desiccant dehumidifier smells
When you first use the dehumidifier and periodically afterwards you might notice a smell coming from the dehumidifier. This is caused by the Zeolite desiccant material and is not a sign that the dehumidifier is faulty, nor is it harmful to humans or pets. The smell occurs because the Zeolite absorbs odours from items like cigarettes, cosmetics, hair sprays, building materials and new furniture and then when the desiccant is heated the smell is discharged into the room. This smell has been described as being like a burning smell or a sour smell. It is normal, will not last long and is not a sign of a fault. If you prefer you can put the dehumidifier in the garage and run it on Laundry mode there to get rid of the smell outside of the house.
The fan light is flashing
If one of the following events happens then the control panel will lock up and the fan light will flash.
- Temperature below freezing
- Temperature above 40°C
- Relative humidity below 40%rh
- Machine has been working hard and needs to cool down internally
If you find that this happens and you none of the buttons on the control respond then do not worry, this is normal and the dehumidifier will start to work again when the conditions allow.
What can I do about the check light on the DD8L?
The alarm light on the dehumidifier could mean that it is being used at too low a temperature (below freezing), too high a temperature (above 40°C) or that the air flow is being blocked. If the temperature is ok then make sure that the filter is clean and that it is far enough away from the wall to allow the air to flow through (at least 30/40cm).
If it becomes a regular issue then call the office on 01483 234900 for further help.
73 Responses
What setting cost more to run on the Meaco deccadent dehumidifier junior high 4 stars or laundry mode ?
Angela
Thank you for your enquiry, laundry mode will be use more energy as it looks to achieve drier air than the other modes.
For more information on running cots, please visit the technical overview tab on the product page.
I hope this helps.
Omar@Meaco