A garage is one of your home’s truly multi-functional spaces. It can be a workshop, a laundry room, a home gym, a dance studio, a storage unit… or you could even do something bizarre like park a car in there.

However, as useful as garages can be, they’re not the most controlled environment in your home. Frequently garages aren’t connected to the main HVAC system, which means they’re subject to temperature fluctuations, stale air and excess humidity. 

If you smell that tell-tale, nostril-tickling odor of mold or mildew in your garage, it’s time to take decisive action.

Here’s a quick guide to garage dehumidification, including easy fixes and some more substantial long-term solutions.

A Quick Guide to Garage Dehumidification

Before we work on making your garage a safer place for your stuff (or your car), let’s start with the fundamental question:

Why do garages get humid in the first place?

There are a few key factors that contribute to all that extra moisture. If you live in a humid climate, there’s already water in the air. When warm, wet air enters a cooler space, like your garage, condensation can form. That leads to a dark, warm, damp environment where mold and mildew can thrive.

The design of your garage can be a factor, too. Garages are frequently under-insulated (or not insulated at all). Inadequate ventilation and gaps where drafts can get in are also contributors. Even your garage floor, if unsealed, can absorb moisture from the ground and let it seep into the garage space.

Even the way we use a garage can worsen humidity. Storing items like canoes, kayaks and tents, parking cars after a rainstorm, and running laundry all help add moisture to the air.

How to dehumidify your garage

Here’s a quick to-do list that will help you dry out your garage:

• Find the problem areas. Look for signs like water stains, mold, mildew, condensation and standing water. Find these and you can target your dehumidification efforts.

• Get the air moving. Pick a sunny, warm day to open the garage door and any other doors and windows in the space.

• Treat mold and mildew. Use bleach-based cleaning spray on these stains. If you see black mold, however, consult a professional for remediation.

• Run a dehumidifier. You can rent an industrial dehumidifier from a hardware store, or use a consumer-grade one if you already have one.

• Use chemical absorbents to further reduce moisture. You know the silica packets that say DO NOT EAT? Those help keep humidity out of your new shoes/new phone/new bag of jerky. You can buy scaled-up versions of these desiccants for your garage.

• Seal cracks and leaks. Weatherproofing will help reduce humidity and regulate the garage’s internal temperature.

Long-term solutions for a climate-controlled garage

The steps above will help get your garage’s humidity down to a reasonable level, and will help mitigate any mold or mildew that already exists. These next few options are more involved, but will help make your garage’s climate more stable.

Insulation and Weatherproofing

Proper insulation and weather-proofing are fundamental for preventing humidity in your garage. 

Insulation such as foam boards or fiberglass create a barrier that prevents warm, moist air from entering and cool air from escaping. This helps control humidity and improves energy efficiency.

Sealing gaps around windows, doors, and other openings is also a good time investment. Use weatherstripping and caulking to block any potential entry points for moisture. Installing door sweeps on the big door can also help prevent water and humid air from seeping in.

Advanced Climate Control Solutions

Apply waterproof coatings or sealant to your garage floor to prevent moisture absorption through the concrete slab. Epoxy coatings, for example, create a durable, water-resistant surface.

If you plan to use your garage as a functional room—a gym, workshop, band rehearsal space—it’s worth investing in a permanent solution. 

Many garages aren’t on the primary HVAC system for the home. Tying in your garage to your HVAC, or adding a mini-split air conditioner, can make your space drier and more liveable. 

Regular maintenance practices

Once your climate is under control, it’s important to regularly inspect the space for signs of moisture, mold or mildew. Check insulation, weatherproofing seals, and climate control systems to ensure they are in good condition.

The most challenging but crucial step: Keep your garage clean and well-organized. Clutter can trap moisture and obstruct airflow. 

With a combination of quick mitigation, permanent climate control, and regular maintenance, you can have a clean, dry, safe and functional garage year-round. 

Have more questions about HVAC for your garage? We’re here to help. Contact us today!