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7 Ways to Maximize your Garage Air Conditioner

There are many reasons why you may want a climate controlled garage. You may be using it as a workshop, a storage area, or simply a hangout space. 

Even if you’re not using it as a full-time space, there are many benefits to having a temperature-controlled garage.

These include:

Year-round comfort

Instead of baking-oven heat in the summer and breath-freezing cold in the winter, a garage AC unit with cooling and heating functions ensures that garage dashes are a thing of the past.

Humidity control

During the warm season, excess humidity can form in enclosed spaces such as the garage and cause a number of issues, including:

  • Cracking and warping of wooden beams and supports
  • Mold and mildew formation
  • Dampness and moisture damage to cardboard boxes and their stored contents 


A garage that’s cooled by using an extended duct from the whole AC unit can cause negative pressure inside the house. When this happens, the home interior will have less pressure than outside, which will draw in air that will bypass HVAC filters.

This outside air pressure can bring a raft of dust, allergens and pollutants and degrade home air quality.


The negative pressure also makes it harder to keep the home cool, due to the constant flow of warmer air coming from outdoors. This can strain the central AC, shorten its operational lifespan, and lead to higher utility bills.

How to Maximize your Garage Air Conditioner

Whether you have a portable AC, a through-the-wall unit, or a mini-split system, achieving maximum efficiency is important to get the most out of the garage air conditioner, for the least utility cost.

Here are eight ways you can maximize its operational efficiency.

When Choosing a Garage AC Model

Ensure proper sizing

Even before getting an air conditioner for your garage, you must ensure you have the right AC size to adequately cool the space. An undersized unit will not be able to cool it sufficiently, while an oversized unit will be inefficient and waste kilowatts. 

To determine the right size for your garage, get its dimensions and plug it into our 

BTU Calculator. This will tell you the right BTU capacity you need for your particular space.

Inverter technology

An inverter AC is able to adjust its output capacity to suit the cooling need. The inverter directs the compressor unit to either increase or decrease the output based on the garage’s air temperature, instead of operating at full volume all the time.

This translates to a more efficient operation, longer life, and lower utility bills.

Look for a SEER2 rating

The SEER or Seasonal Energy Efficiency Ratio measures the AC unit’s energy efficiency. However, the EPA has come up with a new standard for 2023 called SEER2, which provides a more accurate measurement of efficiency. To maximize your investment and ensure your garage AC is up to standard, look for a SEER2-ready model.

Garage Improvements You Can Make

Insulate the garage door

Other than your car, the garage door is the biggest moving piece of equipment you have in the garage. It’s also one of the biggest heat traps. A metal garage door can absorb an incredible amount of heat during the day, especially during the hot summer months. 

To remedy this, you can:

  • Use batting insulation to minimize the amount of heat getting absorbed by the folding steel door and frame
  • Use reflective insulation or foam board to cover up a flat door
  • Place insulating strips around the frame.

Check the ceiling

After the garage door, the ceiling is the next biggest source of heat. If there is an attic above it, consider adding some rolled insulation, or if your garage is a one-story affair, add the insulation to the garage ceiling itself.

Wall improvements

Exposed garage walls can greatly contribute to heat absorption and retention. If you’re on a tight budget, you can choose to insulate only the walls that face the most sunshine.

On the outside, shade placement can also do wonders. Plant trees or greenery to block out some of the sunshine. Even a half hedge or shrubbery can do wonders for shielding exterior walls from direct sunlight.

Cover the windows

Finally, windows represent another area for absorbing outside heat. While they represent just a small percentage of heat entry, windows that face the sun for hours each day can add up to a substantial amount of heat retention. The direct sunlight they let in can also damage stored equipment.

  • Cover windows with tint to limit sunlight and UV entry.
  • If you would rather have clearer windows, use a reflective film that limits the heat without sacrificing clarity.
  • If visibility isn’t an issue, use sun-blocking curtains.
  • Check if the weatherproofing remains good, soft and pliable. Rubber tends to get brittle, and hard or cracked weatherstrips should be replaced to keep out the elements and prolong your AC’s life.

Mickey Luongo

Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.

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