Garage Dehumidifiers: Why You Need One & Which One Is Best


I’ll bet you’re in one of two camps right now:

  • Your garage freezes in the winter and you need to heat it up, or…
  • You’re like me and you need to lower the humidity level so you don’t sweat as soon as you get out of your car.

If you’re REALLY unlucky, you live somewhere that you need to do both.

I’m sorry. That really sucks.

But even if you don’t live in the hot and humid South, you need to keep the humidity level in your garage under control. High humidity is bad for your tools, your car and any electronics or paper items that you’re storing in your garage.

An air conditioned garage would solve that problem, but I can’t name a single person who has the money for one.

But you CAN do something about the humidity in your garage without needing an air conditioner and that’s what we’re going to talk about here.

When Do You Need To Use A Dehumidifier?

To answer that, I want to get a little more scientific than “wow…it feels humid today.”

To do that, we’re going to need a device called a hygrometer.

A hygrometer is a device that measures the amount of water vapor in the air – more commonly called relative humidity.

If you don’t already have a thermometer\hygrometer combo device, I recommend picking one up, because you need to look at both temperature and relative humidity together.

Hygrometer
Believe it or not, this isn’t the worst I’ve seen it inside my garage.

Hygrometers are around $10 on Amazon (link here) and there’s literally over a hundred different ones to choose from.

Don’t go crazy and buy an expensive hygrometer unless you really like one of the features it has. Any cheap digital one will do.

If you measure the relative humidity of your garage with a hygrometer and it reads higher than 50%, it is probably time to think about buying a dehumidifier.

Will A Dehumidifier Help Cool A Garage?

Without getting too much into the science (go here if you want that),higher humidity will make our bodies feel hotter than the actual temperature because our bodies can’t perspire and cool off.

In other words, a dehumidifier doesn’t actively reduce the temperature, but it may help you feel cooler.

FFAD3033R1 garage dehumidifier
My Frigidaire 50-pint dehumidifier

A high amount of moisture (humidity) in the air prevents sweat on the skin from evaporating. That means that a humid day will “feel hotter” to us than a less humid day that’s the same temperature.

People in Arizona will often shrug off a 110ºF day by saying “it’s a dry heat”, because of that very same reason.

If you can find a way to reduce the relative humidity level, it can make the air temperature feel five to ten degrees cooler than it actually is. When you’re working in your garage in the middle of the day in mid-August, ten degrees cooler can make all the difference. 

That said, bear in mind that a dehumidifier isn’t designed to cool your garage. If you’ve added a dehumidifier and still find it too hot, check out my article on garage cooling ideas and also see which garage fan I bought to really cool things down.

How to Choose The Right Size Dehumidifier Your Garage

The size of a dehumidifier is determined by how much water it can pull from the air in a twenty-four-hour period. You’ll commonly see them listed in pints (30 pint, 50 pint, 70 pint, etc.).

To figure out what size is best for your garage, you need to answer two questions first.

Don’t worry…they’re easy questions and I’ll help you through each one.

First: How big is your garage?

The first thing you need to do is to measure your garage’s square footage. Just grab your trusty tape measure, determine the length and width of the room and multiply those two numbers together.

As an example, my garage is 20′ in length and 23′ wide (rounding up). That gives me 460 square feet of space in my two-car garage.

Second: How much moisture do you have in your garage?

Now that we know how big your garage is, we need to know how much moisture you need to pull out of the air.

This is subjective, but here are some guidelines to help you out.

EnergyStar.gov breaks down how much moisture is in your room like this:

  • Moderately Damp: The room feels damp and has a musty odor only in humid weather.
  • Very Damp: The room always feels damp and has musty odor. Damp spots show on walls and floor.
  • Wet: The room feels and smells wet. Walls or floor sweat or seepage is present.
  • Extremely Wet: Laundry drying, wet floor or other high load conditions.

Unless your garage has leaks, mold, or other moisture issues, you’re probably in the “Moderately Damp” category.

If you DO have leaks or damp spots on the wall then I highly recommend you fix those first.

Third: Use this chart to tell the smallest dehumidifier you need

This gives us two important pieces of information about your garage. We know the moisture level that you need to remove and the size of the room overall.

Now what do we do?

Well, that article on EnergyStar.gov I referenced earlier also included a chart with recommended dehumidifier sizes that I’ve reproduced below.

This chart is broken down into how many pints of moisture the dehumidifier would need to pull out of your garage in a 24-hour period based on the moisture level of your garage.

The number in the box represents the smallest dehumidifier that you need.

Moisture Level500 sq.ft1,000 sq. ft1,500 sq. ft2,000 sq. ft2,500 sq. ft
Moderately Damp10 pt.14 pt.18 pt.22 pt.26 pt.
Very Damp12 pt.17 pt.22 pt.27 pt.32 pt.
Wet14 pt.20 pt.26 pt.32 pt.38 pt.
Extremely Wet16 pt.23 pt.30 pt.37 pt.44 pt.

These recommendations are for your home in general and aren’t specific to your garage. Your garage isn’t usually insulated so it’s a little more hostile of an environment.

When in doubt, go with the dehumidifier that covers a slightly larger square footage or moisture category.

I’m willing to bet that you need a smaller dehumidifier than you think. I bought my dehumidifier without putting a whole lot of thought into it. I over-bought for the size of garage I had and spent more money than I needed to.

Don’t Overbuy (Like I Did)

What would a buyer’s guide be without an example of what not to do?

So let me continue with my example,

My 460 sq. ft garage feels like it’s in the “Moderately Damp” category. There aren’t any obvious water leaks or damp spots on the floor, but it does feel pretty hot and humid.

Based on the recommendations above, I could get away with a 10 pint dehumidifier for my garage.

The smallest dehumidifier commonly manufactured is 30 pints. That should be more than enough to handle my size garage, even in “extremely wet” conditions which, if you remember from above, covers things like drying laundry.

What I actually bought was a 50 pint dehumidifier, which was overkill.

As I said before, I bought my garage dehumidifier before I’d seen the recommendations from EnergyStar, so I bought into the manufacturer’s recommendations.

The trouble is that the guidelines they give, will plan for the absolute worst case scenario and not what the average consumer needs.

Consumer Reports has repeatedly found that manufacturers are pretty accurate with their metrics. In other words, they consistently pull as much moisture out of the air that they advertise (source).

Armed with that information. the bottom line is a 30-pint dehumidifier is more than enough for most garages (less than 1,000 sq. ft.) – even for very wet conditions.

In fact, the only time you really need a heavy duty garage dehumidifier is if you already have a mold and mildew problem, or if you have a lot of moisture in the garage from an aquariums or a garden.  

The Best Garage Dehumidifier (An Owner’s Humble Opinion)

I picked up the Frigidaire 50-pint FFAD5033R1 dehumidifier back in June of 2018 (link to Amazon). Other than being one size too big for my garage, I couldn’t be happier with it.

As much as I like my 50-pint dehumidifier, I highly recommend the 30-pint version instead. For the majority of homeowners, the Frigidaire FFAD3033R1 is more than enough.

You can find it on Amazon for well under $200.

At the end of the day, a dehumidifier is an appliance. You’re not going to fall in love with it, but you want to get one that has some great features and is reliable.

My 50-pint Frigidaire works overtime in the Florida summers (which last pretty much all year) and has never given me trouble. I can’t speak to the long term reliability, but I can honestly say that it’s a work horse.

I’m confident that it’s going to keep working well for years to come.

What I like

Digital controls: Frigidaire calls it their Ready-Select controls, but really it’s just a digital readout and control panel.

It’s got all of the controls that you expect: fan speed, timer controls, even warning lights for when you need to replace your filter and when you need to change the water bucket.

You can set the humidity to a desired level and this dehumidifier will work to get it down to that point and then shut itself off.

This isn’t a radical new feature. Dehumidifiers have had something like it for years. But I like when it’s simply implemented and simple to use, like it is here.

Energy Efficiency: Like air conditioners, dehumidifiers use a lot of energy, so its important to get one that’s as easy on your electric bill as possible.

If you look at the three Frigidaire dehumidifiers, power usage varies wildly between the three models. The 70-pint model uses a whopping 740 watts at full power. The 50-pint FFAD5033R1 that I bought still uses 530 watts at full power which is above the average for dehumidifiers in it’s class.

Compare that to the 30-pint FFAD3033R1 which uses only 320 watts – about 100 watts less at full power than the older FAD301NWD that it replaced. I’ll go into more of the differences in a separate heading below.

It’s super quiet: My parents had a dehumidifier when I was growing up and I distinctly remember it sounding like a jet engine. You couldn’t watch TV with it on because you couldn’t hear anything that was going on.

So I was really pleasantly surprised when this one was about as quiet as a refrigerator. You can definitely have it going when you’re working in your garage and still listen to music in the background.

Side hose outlet: Depending on how you have your garage set up, this may be something you really like, or something you don’t.

Personally, I like that the hose outlet is on the side of the unit and not on the back. I don’t have a drain in my garage floor, so I have to run a hose out to my garage door. Manufacturers recommend using a hose that’s less than six feet in length so that doesn’t give you a whole lot of options where to place your dehumidifier in your garage.

The side hose outlet lets me still see the digital control panel without moving the unit, while keeping the hose close enough to the door so it drips directly outside.

It’s not perfect, but it does offer a “set it and forget it” kind of environment.

What I don’t

If you’ve been reading this site for a while, you know I’m a bit of a geek. I love smart devices that can be programmed or use voice commands to turn off and on.

The R-model Frigidaire dehumidifiers let you program for a specific humidity level, but what I really like is to use my Google Home to remotely turn on and off my appliances.

It’s a niche use-case, I know.

I use a two outlet smart-switch that also controls my Air King garage fan. The problem with my dehumidifier is that because of the digital control panel that I really like, it doesn’t default to “on.”

This means that if your power is cut, or you use a switched outlet or power-strip like I do, the dehumidifier won’t automatically resume.

It’s not the end of the world and certainly not a deal breaker, but it’s a useful feature to have in a garage dehumidifier.

FFAD3033R1 vs FAD301NWD

Frigidaire makes two models of 30-pint dehumidifiers, so it’s worth going over the differences.

The FAD301NWD (pictured below) originally came out back in 2013 and was replaced by the FFAD3033R1. Frigidaire still manufactures both because there are a few differences.

The obvious difference is that the older FAD301NWD has a simple dial control, not the digital readout of the newer model. As I mentioned earlier, I love being able to set my dehumidifier for a specific humidity level and have it figure things out on it’s own.

Under the hood, the electric motor in the newer FFAD3033R1 rated to do the same job with less energy usage (source), which is really important. Dehumidifiers are usually energy hogs, so I appreciate anything that will save money on my monthly electric bill.

From a consumer angle, the two models are only separated by about $15 in cost, so it’s worth going for the newer, more efficient FFAD3033R1 if possible.

Frigidaire, White 22-Pint Dehumidifier - FFAD2233W1
$204.00

This dehumidifier removes up to 22 pints of water per day, drying the air quickly and efficiently. Rolling casters and integrated side handles make it easy and convenient to set up and store.

Buy Now
We earn a commission if you click this link and make a purchase at no additional cost to you.
10/18/2021 01:57 pm GMT

One Final Note: When Is A Dehumidifier Not Worth It? 

A dehumidifier can make a big impact in making your garage more comfortable. But there are cases where buying a dehumidifier is just not cost effective. 

For example, if you’re constantly opening and closing your garage door, the air outside will raise humidity levels so quickly that your dehumidifier won’t be able to keep up.

Opening your garage door for minutes at a time can take hours to get the humidity level back under control.  

Similarly, if you don’t have a heated garage, a dehumidifier won’t work well in the winter. Most dehumidifiers won’t work effectively in cold temperatures because the coils will freeze up. 

Manufacturers recommend that you don’t use a dehumidifier when the temperature is lower than 60ºF. If you have a cooler garage and you still need a dehumidifier, be sure that you’re buying one that’s specifically designed for lower temperatures.

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