Garage HVAC: An Ultimate Guide

Garage HVAC: An Ultimate Guide

Your garage is hot and stuffy, so you’re probably wondering if you should install a HVAC system.

This will heat, ventilate, and air condition your space. 

Can’t you just use an exhaust fan in the garage?

If you experience mild summers, an exhaust fan could be all you need to keep your garage cool, but it might not be enough. 

An HVAC system can help you in various ways, such as by keeping your air nice and cool, keeping you comfortable, and keeping your home air-conditioning expenses low.

This is because cooling the garage can help to cool other areas of the home. With that in mind, let’s look at everything you need to know about garage HVAC. 

Garage HVAC Benefits

Garage HVAC Benefits

There are many benefits to installing HVAC in your garage. Let’s look at them. 

You can improve your indoor air

Did you know that the quality of your indoor air can be up to five times worse than outdoor air (via SFGate)?

This is because air becomes trapped in the home. An HVAC system can be useful to improve the indoor air quality because it exchanges stale air for fresher, purer outdoor air. 

You can save energy in the home

Your garage gets very cold in the winter and then hot in the summer, so an HVAC system that has heating and cooling features will help to regulate the temp. This will save on energy costs.

You will reduce humidity

Your garage can become humid and this can spiral into other problems, such as the production of mold growth. How an HVAC system prevents this is by ensuring greater circulation of air.

It continues to draw moist, warm air out of the garage and replaces it with cooler, dry air, therefore keeping your garage low on humidity. 

You make the garage more comfortable

If your garage is your man cave, the last thing you want is for the air inside it to feel stuffy and uncomfortable!

Even if you’ve turned your garage into a workshop, the last thing you need is to feel hot and uncomfortable when using it. 

You keep your garage items safe

Your power tools can be damaged by being stored in freezing temperatures, because their plastic and metal components will become weak and break.

Similarly, the humidity can cause tools to rust and other items in your workshop, such as those made of wood, to absorb the moisture and expand or warp.

Therefore, maintaining more balanced temperatures with the use of an HVAC system will help to prevent such problems from occurring.

Best HVAC Systems For Your Garage

Garage HVAC Benefits

Now that you know what the benefits are of installing HVAC in your garage, let’s check out the different types of HVAC systems that you can install. 

Zoned HVAC

This type of system can cool or heat certain areas of your home, so it’s useful if you want to use the HVAC on a some areas but not all.

How it works is that it regulates zone valves inside the vents to block the flow of air. These systems are a useful way to save money if you only want specific areas to get their benefits. 

Window Air Conditioners

These are popular and widely available. How they work is that they send all the hot air outside so that warm air can be replaced with cooler air.

They’re pretty versatile because small units can cool areas that are around 100 to 300 square feet, while larger units can help to cool areas that are up to 600 or more square feet.

Window ACs can cool more than one room at a time, but you just need to ensure that you place them correctly, such as in the wall holes or windows. 

They’re a good choice for you if you want a fixed window air conditioner that you don’t have to move into another location as that can be difficult to do. 

Portable Air Conditioners 

An alternative solution to a window air conditioner is a portable air conditioning unit. How it works is that chemical refrigerant will move through coiled tubes to absorb heat inside the home, then release it via an exhaust hose.

How this varies from a window air conditioner is that a window air conditioner releases heat via the unit’s component that’s outside the window. 

However, you still need to ensure the exhaust hose will be outside the window, so you can’t really move these types of air conditioners around whenever you want. Their “portable” name is a bit misleading in this regard!

That said, they can be beneficial if you don’t want to block the light coming through a window with a large air conditioning unit.

Best of all, they’re a quick and easy way to start using a conditioning system because you can use them without having to spend a lot of time installing them. 

They’re also a great choice for you if you want to boost the efficiency of your central air conditioner by targeting warm spots in the home, such as in the garage, because they work best if you isolate that room from others – that’s exactly what you can do with your garage. 

Through-The-Wall AC 

As its name suggests, this type of air conditioning unit is installed in a wall. A hole needs to be cut in the wall where a metal sleeve will be placed and this enables you to remove the AC unit whenever you need to.

The benefit of this AC system is that you can cool your home if you don’t have a window in your garage. It also costs less than a split-system unit, which we’ll get to later in this article. 

Through-the-wall AC is also ideal if you’re using your garage for relaxation because these systems aren’t noisy. This is as a result of how most of the unit is placed outside of the garage.

That said, it’s worth bearing in mind that these systems won’t necessarily heat up the space to your liking and this is because, while some of the units can heat up your garage, they are not heat pumps and so they won’t produce as much heat.

That’s something to consider if you live in a cold climate. 

Commercial AC

A commercial-grade AC can be used in the garage and it’s a good choice to consider. This is because of how it’s made.

Commercial air conditioners, although a bit more expensive than other AC types, are made with heavy-duty and durable materials to withstand harsh conditions. These air conditioners can be split into three categories. Let’s look at them in a bit more detail. 

Single And Multi-Stage Systems 

Single-stage HVAC is a good choice for people who live in cold regions and hot, humid areas.

However, one of the things to bear in mind about this system is that it means your heating or cooling system will be running at full capacity even when this isn’t really required.

To solve this problem, a multi-stage HVAC system ensures you can save money and energy. How it works is that you will have a single-stage HVAC system with variable fan speeds to create variable air flow in your garage (via HGTV).

  • Single-split systems are ideal for small offices and garages because they’re efficient and compact, while also being kind to your pocket. 
  • Multi-split systems are pretty similar to single-split systems. They make use of an outdoor unit that connects to multiple indoor units. This is ideal for cooling down medium-sized spaces. 

VRF Systems 

VRF stands for Variable Refrigerant Flow, and this system is ideal for providing medium to large spaces with air conditioning services.

One of its biggest benefits is that it can heat up one space while cooling another, and do this at the same time without putting too much pressure on the air conditioning unit. 

Residential VRF systems are similar to traditional AC systems. They basically contain indoor fan coil units as well as outdoor condenser units to help to cool down the air.

This is beneficial because it sends different quantities of refrigerant to evaporators in the system that regulate different spaces. This is useful for meeting your air conditioning requirements in different areas of the home, such as different rooms. 

How To Calculate How Much AC Energy You Need

You’ll need to figure out how much power your AC should have so that it will appropriately cool down and heat up your garage space. For this, you need to obviously take your garage dimensions into account.

You also need to know that air conditioners make use of British Thermal Units (BTUs) measurements. By knowing the BTUs that you need for the space of your garage, you’ll be able to find the best air conditioner for your space.  

Here’s a useful guide (via PickHVAC) that shows you the amount of BTUs you need for the size of your garage: 

  • If your garage is between 150 to 250 square feet,  you’ll need to ensure your air conditioner can provide 8,000 BTUs. 
  • If your garage is between 250 and 350 square feet, you’ll need 10,000 BTUs. 
  • For a space that’s 350 to 450 square feet, you’ll need 12,000 BTUs. 
  • If your garage is 450 to 550 square feet, you’ll need 14,000 BTUs. This is usually the size of a two-car garage. 
  • If your garage is 550 to 650 square feet, you’ll do well with 16,000 BTUs. 
  • Bump that number up to 18,000 BTUs if your garage is 650 to 750 square feet in size. 

Once you have determined the above, there are some important tips to bear in mind as you might need to have more BTUs than what your garage space requires.

For example, if your garage isn’t insulated you should add approximately 2,000 BTUs. If you live in a very sunny and/or humid climate, you should also add about 1,000 or 2,000 BTUs. This is because the air conditioner will be able to work faster and make the space much more comfortable. 

It’s important to remember that too many BTUs – in other words, having an air conditioner with more BTUs than you need in your garage space – can backfire.

If you don’t take your garage size into consideration and opt for an air conditioner that offers loads of BTUs, this could cause the unit to cool your air too quickly and then cycle off before cycling again very quickly.

This fast cycling can overwork itself and shorten your AC unit’s lifespan. It’s also worth bearing in mind that having too many BTUs will cool the room very quickly but then this will have the unpleasant effect of making the room humid. 

What’s The Best AC Temperature?

The temperature of your AC is something you should bear in mind. Although you’ll obviously want to adjust your AC when the weather starts to get hot, you need to be careful because you don’t want your energy bills to increase a lot. 

It’s not always easy to know what the best temperature is for your home and/or garage. A good place to start is by choosing to put your AC at 78 degrees Fahrenheit. This is an ambient, ideal temperature that will keep you cool inside your garage without notching up costs. 

This temperature is also perfect for helping you to make adjustments to the indoor air. Basically, if 78 degrees feels comfortable, increase it by a degree and see how far up you can turn it while still feeling that your indoor air is comfortable.

If you feel that 78 degrees is not comfortable, then you can cool it down by one temperature and see how far you go to get the best temp. 

You should take the time of day into account, though. When you’re working in your garage, the AC can be at 78 degrees or a bit lower or higher depending on what’s comfortable.

When you go to bed, you should try to make the AC a few degrees warmer because the temp will likely have cooled down. This will also save on your energy bill.

When you leave the house, try to put it several degrees higher as that will further decrease your energy expenses but the AC won’t have to work too hard to cool your indoor air when you get home. 

What About Running AC In Cold Weather?

What About Running AC In Cold Weather?

We’ve talked about how to find the ideal indoor temp when it’s warm outside, but what happens when it’s winter?

When the weather is really cold, this affects the functioning of your AC unit. That’s why running your AC in very cold weather is not recommended. 

ACs that have condensing units contain oil that lubricates their compressors. This is a heavy-grade oil that is meant for use in warm conditions because it becomes thick when the weather is very cold, and that prevents it from properly lubricating the compressors

This is why it’s said that you should not use your AC for long periods of time if the temperature outside is lower than 58 degrees Fahrenheit. Of course, there is an exception to this rule – if the AC model has been built in order to be run safely at extremely low temperatures. 

Do You Need To Insulate Your Garage If You Have HVAC?

Do You Need To Insulate Your Garage If You Have HVAC?

You might think that if you have HVAC installed in your garage that you won’t need to insulate this room of the home. But you should! Making sure that the garage door, ceiling, and walls are insulated will help the general energy efficiency of the garage. 

Insulation is important to prevent your air conditioning system from having to work so hard. It also prevents your garage from experiencing extreme temperature fluctuations, and this will contribute to the efficiency of your HVAC. 

If you’re using your garage for multiple functions, such as a home gym and a workshop, you might wonder if you should partition it so that you can only use the air conditioner in one or some parts of it.

The most important rule is to make sure you install your air conditioner in an area of the garage where it’s most required. Think about the needs of the room and where the air conditioner will be most useful. 

If you want different temperatures in different areas of a large garage, a zoning HVAC system could help as it will enable you to set different temperatures for different spaces.

You can also supplement the air conditioning system with the use of fans, such as if you want to cool down one area of the garage quickly and effectively. 

You can also partition your garage so that its different areas are properly defined and separate from each other. If you do that by adding a wall to your garage, you could use smart HVAC to ensure that you have different temperatures in different areas. 

Related Questions

Should you insulate your HVAC ductwork? 

You should insulate the ductwork as this will improve the efficiency of your HVAC system. This makes sense if you think that the ductwork is used for the forced transportation of air. 

What, exactly, is smart HVAC? 

Smart HVAC systems make use of technology to enable them to function more effectively than traditional HVAC, such as by having variable speed compressors.


Installing an HVAC system in your garage is a good idea, as long as you’re not trying to run an AC in extremely cold temperatures.

In this guide, we’ve outlined everything you need to know about garage HVAC systems so you can stay cool and comfortable when you’re in your workshop or man cave. 

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