How to choose a dehumidifier or size a dehumidifier?

How to Choose a Dehumidifier?

Choosing which dehumidifier to purchase can be a very confusing decision because they all look alike and there are many misconceptions on what a dehumidifier is and what it is suppose to do.

When choosing a dehumidifier you want to purchase the correct dehumidifier size and type to eliminate your moisture and humidity issues. There are many dehumidifier models on the market and the difference in the price will vary based on the extra features they come with plus 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 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. You have to remember that when a manufacturer makes a claim as to how large an area a dehumidifier will dry out they will state it in square feet and it will be based on an average ceiling height of around 8 feet. Therefore, if you have a 1000 square foot area with a 12 foot ceiling and purchase one that claims coverage for 1000 square feet you could be in for a disappointment because in reality you needed one with 50% more capacity or one rated for 1500 square feet. Furthermore, when figuring out the size of the area you need to include the entire open area including 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 close the door to shut 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.


What part of the country do you live in?

The part of the country you live in will dictate how much moisture will be in the outside air and so will dictate how much dehumidification will be necessary. Also, if you live in Florida, Texas, and the gulf regions of the United States you will find a need to dehumidify most of the year, especially in the fall, spring, and the summer. People living on the west coast will find the need to dehumidify in the wintertime because this is the rainy season with the summer being hot and 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 you plan on purchasing how much you intend on using it will dictate how much you would want to spend and the quality you are looking for. Obviously, if one intends to turn it on a few times a year for a few days it is not imperative they have the top of the line unit. On the other hand, if you live in Florida or Texas where you may be running a large capacity dehumidifer 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 Fral FDK54 dehumidifier.


What is the air temperature in the room?

This is an important factor from the standpoint of determining whether or not you will need a low temperature dehumidifier. Most dehumidifiers work fine when the air temperature is 68 degrees and higher. Once it gets down to 65 degrees and below it becomes more difficult to remove more moisture so a specialty low temperature model will be needed.


What is the current humidity in the room?

This is important to know to determine the severity of your moisture issues. Anything 60% or higher is considered a potential mold issue.


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 above 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 45%, and some 50%. 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 area 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. If you plan to run it 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. For these 2 situations we recommend you call our product specialists for advice at 1-888-236-7231 Enter 1.


How do you plan to dispose of the water?

Method 1: Manually Emptying the Bucket
This is an important consideration because if you are dehumidifying a small room in your house where the door will be kept closed with the likelihood of removing no more than 10 to 15 pints of moisture per day planning to empty the container is 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 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. Also, one must 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: Connecting a hose and let it drain out continuously
The second method is continuous drainage, which simply is allowing the water that is pulled from the air to drain out through a hose. Most of the time this is a floor drain which works best since the water is flowing with gravity but this can be a sink and in most cases will require you to elevate the dehumidifier due to the sink location being 2 to 3 feet above the floor. The higher the location on the dehumidifier where the hose is connected the better since it 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 find this important as it is one of the deciding factors in making a buying decision for a dehumidifier because they use more electricity than just a fan due to the compressor. Keep in mind that just because a dehumidifier does not come with the Energy Star rating label does not necessarily mean that it is not electrically efficient. The reason is that not all manufacturers will spend the money to go through the approval process and get  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.