Will a Dehumidifier Work In a Garage?


If your garage has a musty smell and feels wet and damp, then it’s important to address the issue as soon as possible. So will a dehumidifier work to reduce damaging moisture levels in a garage?

Dehumidifiers are a highly effective way of reducing the moisture levels in your garage. Desiccant dehumidifiers are able to lower the relative humidity of a room to 40% or lower, which significantly reduces the growth of mold and mildew. It also stops tools and vehicles from rusting and prevents wood rot.

In this article, we’re going to look at the features to look for when purchasing a dehumidifier, how to work out which size you need, and running costs. But first, let’s check out the excellent benefits.

Benefits of a garage dehumidifier

Garages often have a build-up of condensation and a high level of humidity. These can have long-term effects on your house, such as damaging the foundations of your garage and causing tools or vehicles in the garage to rust quicker.

This can also cause an increase in dust mites in your home and garage, and mold and mildew can begin to grow, which can cause respiratory problems and damage your overall health.

Dehumidifiers are a great defense tool for dealing directly with the issue of humidity in your garage. The reduced moisture levels will prevent the growth of mold and mildew, which is vitally important for your health and well-being.

It will also stop the items housed in your garage from rusting so quickly and prevent wood rot in the structure of your garage.

Features you should look for in a dehumidifier

One of the main things that you need to consider when purchasing a dehumidifier for your garage is whether or not your garage is heated.

Two types of dehumidifier

If your garage isn’t heated, then you’ll need a dehumidifier that that will work in cold temperatures. This is because a standard dehumidifier is not able to work in temperatures that are lower than 60°F (15°C).

A dehumidifier that will work in cold temperatures needs to be either a desiccant unit that will work in any temperature or one that is powered by a compressor and has a hot gas defrost function.

Although either will work, a desiccant absorption dehumidifier is usually more effective in cooler temperatures than one that is powered by a compressor. Desiccant dehumidifiers are able to lower the relative humidity of a room to 40% or lower, which should prevent your tools or vehicles from rusting as it is below the rusting point of metal.

Continuous drain-off

There are a few other things that you should look for on a dehumidifier as they will make life easier for you. A continuous drain-off feature means that the dehumidifier can drain the water that it collects through a hose to a sink or drain, rather than collecting it in a tank. This is particularly useful as it means you don’t need to remember to empty the dehumidifier on a regular basis.

Automatic mode

Auto-start is another useful feature as it means that if there is ever a power cut, the dehumidifier will automatically switch itself back on at the same setting it was on before the power failure. This means that you don’t need to worry about it having to be restarted.

An automatic mode is essential as it means that the dehumidifier will turn on when the humidity is high in your garage and switch itself off when the humidity is low enough that it is not needed.

This means that you don’t need to constantly check the humidity level in your garage to determine if it needs to be switched on or not. It also saves a lot of energy as it’s not running when it doesn’t need to be.

What size dehumidifier do I need for my garage?

One of the most important things to do when purchasing a dehumidifier for your garage is to buy one that is the appropriate size for the size of your garage.

This is because a dehumidifier that is too large for the room will generally be switching itself on and off unnecessarily, while one that is too small for the area will struggle to reduce the amount of moisture in the garage.

The capacity of a dehumidifier is measured in pints per 24 hours and there are a couple of factors that determine which size you will need. One factor is the size of the room that is being dehumidified, and the second is the moisture content levels in the room.

What is the size of your garage?

In order to calculate the size of you’re garage, you’re going to first need a tape measure. Measure the length and width of the garage and multiply these two numbers together to determine the size.

For example, if your garage measures 22 feet in length and 25 feet in width, the size is 550 square feet. Always round up your measurements rather than down.

How much moisture is in your garage?

The most accurate way to measure the moisture levels inside your garage is by using a hygrometer. This small device measures and relative humidity, which is the amount of water vapor in the air.

If you don’t already own one, I recommend this inexpensive hygrometer as it also displays the temperature, which is very useful when tackling a humid garage.

You can also determine the moisture levels in your garage by using some common sense. The Energy Star website categorizes the amount of moistureOpens in a new tab. in a room by the following:

  • Moderately damp – In very humid weather the room feels damp, and there is a musty smell present.
  • Very damp – The room always has a musty smell and feels damp. There are often damp spots on the wall or the floor.
  • Wet – The area both feels and smells wet, and the walls and floor often sweat.
  • Extremely wet – The walls and floor are wet, and there is often laundry drying in the room.

Use this chart below (taken from the Energy Star website) to estimate the capacity you are looking for. The number in each box represents the smallest dehumidifier you need.

Moisture Level500 sq. ft1,000 sq. ft1,500 sq. ft2,000 sq. ft2,500 sq. ft
Moderately Damp10 pt14 pt18 pt22 pt26 pt
Very Damp12 pt17 pt22 pt27 pt32 pt
Wet14 pt20 pt26 pt32 pt38 pt
Extremely Wet16 pt23 pt30 pt37 pt44 pt

If you are unsure about which size dehumidifier you should purchase, then buy one that is capable of covering a slightly larger area or a higher moisture category.

How to calculate the running cost of your dehumidifier

The amount of energy that your dehumidifier will use will depend on your current power rate and how many watts the unit uses, so first of all you need to know how much your utility company charges per kilowatt-hour.

The Statista website states that the retail price for electricity in the United States was an average of 10.66 U.S. cents per kilowatt-hour in 2020Opens in a new tab..

Let’s assume you own a standard model that operates at 300 Watts-hour. If the current power rate is 10.66 cents per kW, an electric dehumidifier uses 3.19 cents of power per hour. If you run it for 12 hours a day, the cost is 12 hours × 3.19 cents = 38.3 cents/day or about $140 per year.

Consult your electricity bill

If you want a more precise figure for where you live, you can find this out by looking at your energy bill and checking the rates per kilowatt-hour.

Next, you need to work out how much power your dehumidifier uses. You will need to know this figure in watts, but quite often manufacturers only display the volts and amps.

If yours is in volts and amps, then just multiply the volts and amps to calculate the wattage. Divide that figure by 1,000 to work out the kilowatts.

Once you have your figure in kilowatts, you can then use the price that your energy company charges to work out an estimate of the running costs of your dehumidifier.

Where to place a dehumidifier

Generally, a dehumidifier will have a top-mounted air discharge which means that it can be situated against a wall. However, some dehumidifiers don’t have a top-mounted air discharge, so they should be placed away from any walls or furniture so that plenty of air can circulate around them.

You should also always place your dehumidifier away from anything that could clog it, such as dust, dirt, or woodworking equipment.

When you are using a dehumidifier, you should always ensure that all of the doors and windows in the room are closed so that the unit can work effectively.

Other options to reduce moisture

If you use the area often, especially if you’ve converted your garage into an apartment or living area, then another option would be to install an exhaust fan.

Although an exhaust fan isn’t quite as simple as plugging in a dehumidifier, once installed, it will regulate the temperature of the area and also prevent the humidity from causing problems in other areas of your house.

If you do use your garage as a living area and don’t want to install an exhaust fan, then you could install a ceiling fan instead.

Although it won’t provide as much ventilation as an exhaust fan, it’s a lot easier to install in your garage and is quieter. However, if you choose a ceiling fan, you will need an air vent to allow air into the area.

Thanks for reading!

Graham Walsh

I want to share everything I know about home improvement in order to help you. Whether you're a home enthusiast or an industry professional, I have the information that you need.

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