Does a Garage Need Ventilation?

Have you ever walked into your garage and smelled something really bad? It could be paint fumes, gasoline, fertilizer, or just stale, musty air.

I did recently and it immediately got me thinking about whether or not I should have some sort of ventilation in my garage.  

Here’s what I found out.

Residential garages are not required to have ventilation under ANSI/ASHRAE Standard 62.2. However, the EPA does recommend active ventilation to help get rid of toxic fumes and carbon monoxide. Ventilation can also help with air flow and heating\cooling your garage. 

Even though it’s not legally required, it’s still a good idea to have some sort of ventilation in your garage.

Let’s take a look at some of the reasons why you’d want to ventilate your garage and then talk about some of the solutions.


Is Garage Ventilation Required?

As of the time of writing, ANSI/ASHRAE Standard 62.2 is the national consensus standard on residential ventilation in the United States. It does not require residential garages to be actively ventilated.

However, the EPA (Environmental Protection Agency) does recommend that residential attached garages use either a 100 cfm (ducted) or 80 cfm (un-ducted) fan to vent any toxic fumes directly to the outside. (pdf source)


Why You Should Ventilate Your Garage

Below are some of the reasons you should consider installing ventilation in your garage. 

Toxic Fumes

There’s a lot of nasty stuff in your garage: weed killers, pool chemicals, paint or harsh cleaning supplies.

They all create toxic fumes that can build up to a dangerous level inside the garage. Worse yet, they could potentially seep from your garage into other parts of your home.

Actively ventilating your garage can help fumes dissipate, keeping them away from your family and pets.  

Carbon Monoxide

Carbon monoxide is a toxic fume, but it’s so important it deserves its own section.

Garages are where we store our cars, motorcycles, and gas powered lawn equipment. On a chilly morning, many car owners may want to start their car before driving away. Other times, we might leave it running to enjoy the radio or air conditioning while inside the garage. 

No matter the reason, any time a car’s engine is running, it’s emitting carbon monoxide. In an unventilated garage, this can be very dangerous. Carbon monoxide can leak into the home or even become lethal in large amounts

While it’s no substitute for a good carbon monoxide detector, a well ventilated garage can help prevent carbon monoxide building up to lethal levels. 

Better Airflow

Garages by design, tend to have few entrances and exits for air to flow through. 

With only a single door and usually no windows, it can be tough to get air flowing in and out. With no air moving around. your garage can get pretty stale.

The ASHRAE 62.2 recommends that the air in residential homes be circulated equivalent to 7.5 cfm per person plus 1 cfm per 100 square feet.

While this is for dedicated living spaces and not garages, it’s still important to have air flow in any room where you’re going to be spending an extended amount of time. Its especially important if you’re planning on using your garage as a dog kennel.

Better Cooling in the Summer

Non-insulated garages are rarely insulated which allows for hot air to build up inside. Without proper heating and cooling, garages can become stifling in the warm months and frigid in the cold months.

While a portable air conditioner may eventually be the answer, the first step should be to look at some form of active ventilation. 

Similar to increasing air flow, adding ventilation to a garage can allow some of that built-up hot air to escape.

Water Ventilation

Believe it or not, ventilation can help with water as well. This is called hydraulic ventilation.

These vents are designed to get water out of buildings in flood-prone areas. Through specialized vents placed close to the ground, it helps water pass through garages and lessen potential flood damages (source)

It’s a specific use case that most of us will never need, but it’s worth considering if you live in a flood zone.  


Why Your Garage Might Not Need Ventilation

Not every garage needs ventilation. Usually it depends on how you’re using your garage and how much time you’re spending in it.

Here are a few reasons a garage may not need ventilation. 

Detached Garages

If you own a detached garage, that’s separate from your the home, it may not require ventilation. 

There’s less concern from toxic fumes or carbon monoxide with detached garages because there’s no way for the fumes to get to living areas. You’ll still see benefits from increased air flow and cooling, however.

You’re Not Actually Using It

It happens. Some garages just aren’t in use. Maybe you’re just storing some old items, or it’s empty altogether.  

Either way, if a garage isn’t in use, it probably doesn’t need to be ventilated.


Types of Garage Ventilation

Some types of garage ventilation are obviously going to be better than others. In fact, there are quite a few different types, and at least one that I guarantee you already have.

Let’s take a look at some of the means of ventilating garages. 

Overhead Doors

This is the easy one. Opening your garage door will ventilate your garage as long as you’re using some kind of garage fan to help circulate the air.

Overhead garage doors are standard in nearly every house. After all, you need a way to get your car in and out of the garage.  

The challenge is that you’ll usually need to have another type of ventilation as well. An open garage door will let in insects, animals, leaves and other debris into your garage. It’ll also negate any kind of active heating or cooling you’re using in your garage.

Windows

If you’re lucky enough to have a window in your garage, it’s a great way to keep it ventilated. Just like in your home, windows are a source of ventilation for garages (if they open, that is).

As an added bonus, you can install a small window wan to pull fresh air in from the outside or flip it around to help clear any toxic fumes out of your garage.

Exhaust Fans and Roof Vents

These two solutions often go hand in hand and are some of the best ways that you can actively ventilate your garage.

Exhaust fans are a type of garage ventilation installed through the ceiling or walls of a garage. A hose or duct-work inside your garage connects to the exhaust fan, and the exhaust fan works to pull air from the garage, through the hose, and to the outside (source)

Roof vents are similar, but can be powered or non-powered. They’re a bit more challenging of an installation because the size of the roof vent is dependent on the square footage of the garage’s attic, the roof’s slope, and if the attic has vapor cooling.

Garage roof vents are rated by their “net free area,” or NFA. Experts recommend installing one square foot of NFA per 300 square feet of attic space if a garage’s attic has vapor cooling.

If there’s no vapor cooling in the attic, installing one square foot of NFA per 150 square feet of attic space is recommended (source).

If you’re shopping for a garage fan, check out my ultimate buyer’s guide article. Its choc full of everything you need to know to get the best garage fan, without spending a fortune!