- Temperature of Room – Do you need auto defrost?
- Energy efficiency
- Features and design
1. Room Size and Humidity – Capacity of dehumidifier
The capacity of a dehumidifier is measured by how much water it can remove from the air per day. 30-pint, 40-pint, 50-pint represent the number of pints of water a dehumidifier can remove within a 24 hour period of time.
Always remember that the bucket or tank of the dehumidifier may not accommodate as much water as its capacity, so you might have to empty the bucket several times a day to achieve the maximum capacity.
If you are constantly busy or don’t want to keep on checking the bucket, you can attach the dehumidifier with a hose (which is sometimes included) to direct the water out of the house into a drain.
Here’s a table to let you check how much capacity you need for your dehumidifier:
AHAM Dehumidifier Sizing Guide – Match room or area size to current humidity conditions to find minimum size rating in pints.
|Condition without dehumidification||500 sq. ft.||1000 sq. ft.||1500 sq. ft.||2000 sq. ft.||2500 sq. ft.|
|Moderately damp:Feels damp and has musty odor only in humid weather||10||14||18||22||26|
|Very damp:Always feels damp and has musty odor. Damp spots show on walls and floor.||12||17||22||27||32|
|Wet:Feels and smells wet. Walls or floor “sweat,” or seepage is present.||14||20||26||32||38|
|Extremely wet:Laundry drying, wet floor, high-load conditions.||16||23||30||37||44|
Tip: It’s always better to get a larger capacity dehumidifier than the exact capacity you need because it can remove moisture from the air faster over the same sized area.
That means it doesn’t have to run for a long time and you save electricity charges in the long run. On the other hand, a small-capacity model in a large room might run continuously and still not lower the humidity to an acceptable level.
Example: By referring to the table, let’s say you have a 2000 sq. ft. room which is very damp, you’ll have to remove 27 pints of water per day from the room. If you buy a 30-pint dehumidifier, you might have to leave it running the whole day to accomplish the job. But if you get one with larger capacity, for instance, 50-pint, it will do the job a lot faster.
2. Temperature of Room – Do you need auto defrost?
Standard dehumidifiers only work well when the temperatures is above 60 degrees F. If your room temperature (standard) is above 60-65 degrees F, then you don’t have to worry about the extra feature to take care of the low temperature condition.
If you are looking for a dehumidifier for your basement, it is better to get a “low temperature” dehumidifier or basement dehumidifier.
“Low temperature” dehumidifiers usually have the “frost guard” or “auto defrost” design to let the fan blow warm air to the coil when low temperature is detected. This is to avoid frosting on the coils which can prevent air from going through. If you have a basement that is below 33 degrees F, you may have to consider a dehumidifier that uses a process called “hot gas” to heat the coil.
You can of course buy a machine with frost guard or auto defrost and use it in all the rooms that needed dehumidifying to save money, rather than buying a separate dehumidifier for your basement. But please note that low temperature dehumidifiers are generally noisier than the regular machines that are designed to work above 65 degrees F.
3. Energy efficiency
If you are concerned about electrical costs or the environment, get an Energy Star rated dehumidifier which is 10 to 20 percent more power efficient.
You’ll definitely want your dehumidifier to be very quiet if you’re going to put it in an occupied bedroom to run at night. If that is so, get a model that is praised for its quietness.
But when you read reviews, be aware that “quiet” to one owner may seem “noisy” to another, as we all have different tolerance for noise. It could also be that your house is so quiet even the quietest dehumidifier sounds like a boiling pot.
Who knows how long an electrical appliance can last? Despite all the negative feedback we can see written by irate owners who don’t get their money’s worth, there could be a chance either way.
But just in case, do find a model which has longer warranty period and remember that warranty may not include return shipping costs.
Don’t rely on the manufacturer totally for durability, because durability also depends on the owner to take good care of the machine. You must of course, use it in the proper way and clean it regularly.
To read more about how to maintain your dehumidifier, click here to read my guide on How To Keep Your Dehumidifier Working.
6. Features and design
Before you decide to buy any model, check its features and design as I listed out below. These may not seem very important but you really wouldn’t want to be disappointed because your dehumidifier lacked that one convenient feature.
Bucket or Hose
- – If it is possible to place your dehumidifier so that a hose can be connected to drain the water out of the house, I would strongly recommend you to do so. This will save you a lot of time and energy to empty and clean the bucket regularly, and it will avoid spills. One reviewer pointed out that this is also more convenient for senior citizens.
Otherwise you’ll need the bucket of the dehumidifier to be designed for easy removal, carrying and cleaning. Look at the handle(s) of the bucket. Can you carry it with one or two hands? Is it easy to take out when it’s full?
Most dehumidifiers have indicator light or sound warning when the bucket is full, and will automatically shut off when the bucket is full, tipped or not properly attached.
- – Some models have a pump to pump the water out of the room through the window. This is handy for using the dehumidifier upstairs.
- – You will want controls that are user-friendly. Some dehumidifiers have electronic controls, while some have digital controls. They come with various options such as fan speed, humidistat to control the humidity level, and timer.With a humidistat you can set the humidity level you want the room to achieve, and this should be around 30% to 50%.
The dehumidifier will automatically turn off when the level is reached. This will prevent over-dehumidifying the room (which may also cause problems such as dry skin, itchiness, and cracked furniture), and is power saving.
Check the accuracy of the humidistat with a hygrometer which you can get inexpensively ($20 – $40).
Built-in wheels or casters
- – Not up to carrying the heavy thing around? Remember to have this feature then. Usually only mini or compact dehumidifiers don’t have casters.
- – Check to see which direction the air is going in and out so that you don’t block the dehumidifying process by putting it too near walls or furniture. Some models draw in air through slits in the front which is great if you have to put it right next to some furniture.