Choosing a Dehumidifier

So what does one look for in a dehumidifier? Let’s take a look at some critical features and basic considerations when choosing a dehumidifier to get the most out of your purchase  – with the least headache!

Identify the Proper Humidity to be Achieved

When looking for a good unit, it’s helpful to understand the desired end-goal.  Most sources recommend that you achieve a relative humidity level of between 30 and 50%.

While most people are aware that dank, excessively humid conditions can promote irritating or hazardous fungi, molds and other organisms – as well as simply make a house musty and potentially damage furniture and other interior surfaces – the effects of a home “too dry” are less known.

If you err on making your home’s air too dry by “over-dehumidifying,” then you can create a whole host of other issues that are less than desirable.  For example, very dry air can irritate airways, exacerbate asthma and result in cracked, painful skin conditions.  It can also dry out mucous membranes and create problems for restful sleeping.  Consequently, it’s best to stay withing the 30-50% relative humidity range to avoid problems associated with either extreme.

Energy Efficiency

Although many aspects of dehumidifiers are often featured in product ads, energy efficiency is overlooked or not considered in the buying process.  This is unfortunate, since the savings that can accrue over time with some proper selection based on efficiency scores can be quite considerable.

Probably the easiest, most fool-proof way to ensure that you’ve found a dehumidifier that’s not an energy hog is by looking to see whether its Energy Star Rated (also referred to as Energy Star “Certified” or “Qualified”).  Such models usually come with a tag to this effect. The Energy Star Label was developed by the US Department of Energy (“DOE”) precisely to allow consumers to determine an appliance’s efficiency at a glance.  In order to be adorned with a coveted Energy Star Rating, an appliance must be made to work as well as any other model, but much more efficiently, based on empirically-derived standards set forth by the DOE.  And while you may think this is just another way of crafty marketing, some reports conservatively estimate that buying an Energy Star rated model over a “regular” model can save you in the ballpark of $20 a year, which over the 10-year lifespan of a unit can let you keep an extra $200 of your hard-earned cash – in your pocket where it belongs!

Key Features to Look For

1) Humidistat Control

A humidistat (which functions much like a thermostat) simply allows you to set the unit to a certain relative humidity level so that the unit can cycle on and off as necessary to reach and maintain the desired humidity.  This type of set-it-and-forget-it operation is not only better for you, since you don’t need to manually turn on and off the unit, but it also saves electricity because it means that the dehumidifier only operates the compressor (the heart of the system) when it’s needed, and shuts it down as soon as the proper humidity level is reached.  Without such a control, most models would result in over-drying the air if not monitored constantly.  And conversely, if shut off for too long, an idle unit would result in humidity levels rising above healthy/desired levels once more, making more work for the unit once it’s finally switched on.  In some cases, very small humidifiers don’t have a humidistat, and simply are on or off.  If these are to be used, we recommend attaching them to a timer that switches them on for a few hours (or more or less depending on need) to prevent over/under-drying.  However, for most homes and situations, the bottom line – save yourself some grief and get a dehumidifier with a humidistat!

2) Automatic Defrost

Unless you never plan on operating your dehumidifier at temperatures below 50F, then you will want a unit that comes with automatic defrost.  Compressor-driven models (which are the most common) operate by compressing refrigerants, just like an air conditioner.  However, when the air gets much below 50F, there is a risk of freezing, which can spell bad news for you, and especially your dehumidifier unit.  Most modern dehumidifiers deal with this problem by running through a defrost cycle to prevent freezing, and as the name suggest, they do this automatically so you don’t need to defrost the unit manually.  With this feature, most compressor models can work down to temperatures in the 40s, although models vary – check the manufacturer’s specification to be sure.

In the event you need to dehumidify areas that are likely to drop (while the unit’s operating) below 40F, then the compressor-driven systems might not work at all, or do so very poorly/inefficiently.  In such case, it’s worth considering a different type of dehumidifier – called a desiccant dehumidifier.  These operate by passing air through a humidity-absorbing media that removes the water from the air and holds it in the media, which then acts like a sponge.  Every so often the media is heated, driving the water out of the media and making it available for more work. The system continues to cycle this way until the desired humidity is reached.  In addition to working extremely well at low temperatures, these are nice because they don’t need to employ energy-hungry compressors and other high-draw components.

3) Easy to Use Drain Systems

Most models, especially those built for more heavy-duty work, come with some sort of “continuous” drain system.  Unlike the water receptacles that are also included, these drain systems allow condensate to be channeled to some sort of drain, sump, or anywhere else you can let the accumulated water pass – so you don’t have to worry about manually checking and draining the internal collection bucket.  Of course, if you are using a small dehumidifier and drying small spaces, you may not need any continuous drain, but for larger areas and basements, you will definitely want one.

Among continuous drain systems there are two types – gravity draining systems and pump-type systems.  As you can guess, the first type simply is a drain hose that is designed to let water drip out of a hose passively.  This works fine, but the big hang up here is that you need to locate the drain hose below the unit at all times for the water to actually leak out!  And while that all sounds simple enough, it can – and often does – create problems when people realize that they have few or no floor drains precisely in the areas where they want the dehumidifier to run. This sometimes lead people to set their units high up on chairs, stools or other furniture, which can be a perilous way to run any heavy appliance.

The pump-type drainage systems are much more versatile.  Again, as their name suggests, they use an internal pump that pushes water out of the drainage tube, rather than relying on gravity.  As a result, many of these systems can send water vertically several feet, which allows you many more options as far as outlets.  Now you can discharge water to sinks, other elevated drains, and even out a nearby window (as long as you are not giving anyone an uninvited shower!).  These systems are also good at moving water through several feet of tubing horizontally as well.  Consequently, pump-type drain systems make good choices for basements or anywhere else where situating a gravity-draining system could prove difficult.

Quiet Operation

This is not so much a feature or requirement as it is a consideration.  If you are using your dehumidifier in the basement, and it will be mainly left alone there, then who really cares if its a bit loud and clunky, right?  On the other hand, if the unit is intended to run in the living room while you are entertaining guests or listening carefully to the TV or reading a riveting novel, then the sound of a compressor engaging/disengaging, and lots of fan noise will most likely cause you some measure of irritation.  More than any other, noise is a very subjective thing when it comes to appliances.  Some people find the average dehumidifier very tolerable, while others will insist that anything beyond a virtually silent model is “too loud.”

Because noise level scores are often not provided and, when they are, are usually reported in different ways and are not standardized, we suggest paying close attention to customer reviews and taking note of instances where there are repeated reports of excessive sound levels.  We say “repeated” of course only because, invariably, someone always complains about noise – so a few random remarks in the face of mostly positive comments should not be much of a concern in our view.