How to choose a dehumidifier

How to Choose a Dehumidifier

Shopping for a dehumidifier can be a pretty confusing, and we enjoy getting loads of questions about them all the time. What should you be looking for? With dehumidifiers it isn’t always clear because many models can often look similar and there are many misconceptions about what dehumidifiers can and are suppose to do.

Sizing is the most important thing to remember when choosing a dehumidifier. Finding the correct dehumidifier size and type to eliminate your humidity or possible moisture problem, while not costing you a fortune to run, is very important. There are many dehumidifier models on the market and the difference in the price will vary based on their extra features, efficiency, their size, and capacity. So, we have come up with our top ten list of questions you should consider to help you choose the best dehumidifier for your situation.

Dehumidifier Sizing: what are the dimensions of the area to be dehumidified?

The first thing you need to know is the size of the area you will be dehumidifying. Remember you need to include the space height in the equation because you will be drying the air in the entire space not just along the floor. So, the cubic feet of space is simply the length of the room times the width, times the height, (L x W x H). You have to remember that manufacturers measure their square foot coverage to how large an area a dehumidifier will dry out based on an average ceiling height of around 8 feet.

For example, say you have a 1,000 square foot area, but it has a 12 foot ceiling. If you were to purchase a dehumidifier with 1,000 square feet rating that means you’re only getting 8,000 feet of coverage and you could be pretty disappointed because in reality you needed coverage of 12,000 square feet which is at minimum of 33% more capacity.

It’s also important when figuring out the size of the area you need to include the entire open area with any adjoining rooms it opens to or floors of the house. The reason is that the moisture in the air will always try to equalize itself by moving from areas of high humidity to areas of low humidity. Therefore, for example, if you plan on dehumidifying a 500 square foot area in your basement and the door opens to another area that is 500 square feet you should plan on a 1000 square foot rated unit unless you regularly close the door shutting off the airflow. Finally, look up when you are sizing it too because if you are running it in your basement and it opens to the first and second floor you will be basically dehumidifying the entire house. Furthermore, if the windows are open on the first and second floors you are dehumidifying the neighborhood.


How does location, where you live, affect dehumidifiers? Like Florida?

Should you live in place like Florida, Texas, or the rest of the United States Gulf region, you might need to dehumidify your home most of the year, especially in the fall, spring, and the summer. The local climate of the country you live in can unfortunately determine, how much moisture will be in the outside air and so will dictate the level of dehumidification you might need inside.

If you’re living on the US West Coast will likely need to dehumidify in the wintertime because (hopefully it’s rainy season) with the summer being dry. Then, there are those who live in the semi-arid and arid parts of the country who may seldom find a need for a dehumidifier except for unseasonal rain and humidity episodes. Therefore, like any appliance planning out how much you intend to use it, will determine how much you would want to spend and the quality you are looking for. Obviously, if you’re only turning it on a few times a year for a few days it might not fit your budget to have. On the other hand, if you live in Florida or Texas where you may be running a large capacity dehumidifier up to 8 to 10 months during the year, you would be looking for something that is well built and designed to last like the WhiteWing SuperDry.


How does air temperature affect a dehumidifier’s operation?

The overall room or space humidity you are trying dehumidify will be greatly affected by temperature. When using a dehumidifier higher air temperature means a dehumidifier, when sized right, it should be able to lower the humidity to the desired level. Unfortunately the opposite is also true, the lower the temperature the less control over humidity you’ll have with a dehumidifier.

What temperature you think you’ll be running your dehumidifier at, is an important factor for determining whether or not you will need a low temperature dehumidifier. Most dehumidifiers work fine when the air temperature is 68 degrees and higher. The issue is when it gets down to 65 degrees and below it becomes more difficult to remove moisture so a low temperature dehumidifier would be needed.


How do you determine the current humidity in the room?

Hygrometers are a great way to measure the humidity of a room. It’s easy to find and read, we offer a hygrometer on our site. They’re basically the same as thermometer for temperature, except they measure humidity. Hygrometers are great for understanding the severity of your humidity problem. Should you find anything 60% or higher, unhealthy mold growth is definitely a problem. Most dehumidifiers have another internal meter called a humidistat, which internally measures the humidity and helps the machine keep the humidity to the desired level.


What is the desired humidity you would like to get down to?

In most cases, if you are in need of a dehumidifier the humidity will be 55+% and the result will be the chance of mold, mildew, increased dust mite population, and possible damage to materials in your home. We like to recommend lowering the humidity to 50% to eliminate these potential hazards; however, every person has different comfort levels so some people prefer 40%, some 50%, and many others somewhere in between. The decision to be made is the cost versus comfort factor. The lower you set your humidistat on your dehumidifier the longer it will operate to maintain it. The only exception to this rule would be if one is protecting a musical instrument like a piano where it is recommended to maintain 45% humidity.


What room in your house are you looking to dehumidify?

This is an important consideration due to the difference in the humidity and temperature of the air depending on the location in your house. If you plan to run a dehumidifier in your bedroom you will probably prefer a quiet operating dehumidifier. If you are purchasing a crawl space dehumidifier it will need to fit in the area due to the low ceiling as well as being powerful enough to remove the moisture, especially, if the floor is a dirt floor and not sealed. If one is planning on running the dehumidifier in their basement the tendency will be for the humidity to be higher and the air temperature to be lower. Therefore, an important consideration is can it operate when the temperature goes below 65 degrees. This is what they call in the industry a low temperature basement dehumidifier.


What is the area mainly used for?

If you are storing tools you will want to make sure you keep the humidity at 50% or below. Some other material such as musical instruments would require further dehumidification demands to 45%. If you just want to prevent mold, mildew, and their odors in a basement 50 to 55 percent should be adequate. If the area is used for entertaining you will want to make sure it is dehumidified to maintain a comfortable environment for your company so 45 to 50 percent would be preferable. If you plan on using it in your bedroom or office it will need to be quiet as well as keep it comfortable for sleeping or working. Other contributing factors are human activity or the presence of any open water. For example, if it is an exercise room one must account for the humidity that will be added to the air by the people sweating and breathing. Also, if there is an indoor pool or spa in the room that is not covered or an open aquarium the humidity will be increased in the room due to the water evaporating into the air.


How do you plan to empty of the dehumidifier water?

Method 1: Manually Emptying the Bucket

Every dehumidifier comes with a bucket where it puts the water it is taking from the air. Most dehumidifiers have an auto shut-off so the water will not overflow the bucket and make a puddle around your dehumidifier. If you are only dehumidifying a small room in your home, with a door that’s usually closed the likelihood of only removing 10 to 15 pints of moisture per day is pretty realistic to assume you can just daily plan to empty the bucket is pretty realistic since you would not need to empty the bucket more than once a day or every other day.

If you plan on emptying the container, it is important to find out how large the bucket is, where it is located, is it easy to remove, is it easy to grip and carry, and how difficult is it to put back. Realistically, as the size of your dehumidification job increases the idea of emptying the bucket becomes more and more of a hassle. The consideration becomes two-fold: how often will I need to empty the container and how heavy will it be when it is full. It is also important to remember that if the bucket is not emptied once it is full all dehumidification stops until it is emptied. Therefore, someone needs to be around the dehumidifier so they can monitor this and some models will beep to let you know it is full and/or have a visible light.

Method 2: Continuous Drainage

The second method is continuous drainage by attaching a hose which simply allows the water to be pulled from the air to drain out through a hose. Most dehumidifiers have a hose hook up, though it depends greatly on the dehumidifier of both it’s shape and size. If there is a floor drain, this method which works great, since the water is flowing out of the bucket through gravity. You can also use a sink and in most cases this option would require you to elevate the dehumidifier since most sinks are located 2 to 3 feet above the floor.

A higher location on the dehumidifier where the hose is connected will provide better gravity for the water flow to come out. Most models come with this option and you will find some are simpler to use than others. Some will provide the hose some will not. Some will accommodate your typical garden hose and some will require a specific size plastic hose that slides over the opening and does not screw on. So, check out what is entailed in connecting the hose, does it come with the hose, and if it does not will I need to buy a specific size hose at my local hardware store or can I simply screw my garden hose onto the opening.

Method 3: Pumping out the water

The third and final method is to pump the water out. This is recommended if you’re needing to dispose of the water a significant distance from the unit or in a higher location like the next floor, up and out a window, or up into a sink. Some of the dehumidifiers like the Friedrich dehumidifiers come with a built in pump which simplifies the entire process. Also provided is the drainage hose so all you have to do is connect the hose and turn on your dehumidifier. If your dehumidifier doesn’t come with a pump you will need to place the continuous drainage hose into the reservoir of an external condensate pump that will sit next to it on the floor. Most pumps will supply you with the discharge hose where the forced water will flow through to the location you have chosen to empty the water. About the only issue you may need to resolve is if the location of where you connect the continuous drainage hose on your dehumidifier is at the ground level. Since some of your external condensate pumps are made where the opening to the reservoir where you will insert the hose may be anywhere from 3 to 6 inches off the floor, you may need to elevate the dehumidifier a few inches off the floor to provide just enough gravity for the water to flow into the reservoir of the pump.


How noisy is the dehumidifier?

This is an important factor especially if you’re planning to operate it when people will be around like a bedroom, office, living room, etc. All dehumidifiers have a fan that will make some noise but it is the sound of the compressor is what will make it tolerable or not. Some compressors vibrate and create an uneven buzzing pitched noise which some people cannot tolerate.


Is it Energy Star Rated?

Most people recognize that dehumidifier efficiency, what good is a dehumidifier that costs a fortune to run? It is important enough to be one of the deciding factors in buying a dehumidifier because they use more electricity than just a fan due mainly to the compressor. Keep in mind that not even the best dehumidifiers might not come with an Energy Star rating. Sadly, Energy Star rating label does not necessarily mean the dehumidifier is electrically efficient or even your best option.

A lot of manufacturers will not spend the money to go through the government approval process to be Energy Star certified and this is more common with the industrial and commercial models. So, even though a dehumidifier has an apparent high wattage rating, if it efficiently removes pints of water per kilowatt of electricity used, that really determines how efficient it is. Therefore, you will want to know this value when shopping for one. Remember, less wattage used per hour does not mean less electricity used in the long run if you need to run it more, it will cost more.