Why garages get so hot
Most garages heat up for a handful of common reasons:
- Limited ventilation: warm air collects and has nowhere to go.
- Sun exposure: direct sun on the door, roof and metal surfaces adds heat, especially through a poorly insulated door.
- Poor insulation: an uninsulated or under-insulated door lets outside heat move in easily.
- Heat sources inside: appliances, equipment and a car that was just driven all add warmth.
How your garage door affects temperature
Door color and construction matter. Darker doors absorb more sun, while lighter colors reflect it. An insulated door acts as a barrier that helps keep the temperature inside the garage more stable on the hottest days.
Keeping the door well sealed and in good working order also helps limit how much hot air gets in.
Garage layout and design
Insulation in the walls and ceiling helps keep heat out. Windows or vents let air move through the space, and shades on windows can block strong afternoon sun, which matters most for a west-facing garage. Reducing clutter also improves airflow.
Risks of an overheated garage
Too much heat can cause problems over time:
- Stored items: paint, electronics and tires can deteriorate in high heat.
- Door equipment: openers and moving parts can wear faster. An opener can also overheat if the door is run many times in a short period.
- Comfort: a garage used as a workspace or hobby area can become uncomfortable or unusable.
Ways to keep a garage cooler
Practical steps homeowners can take:
- Improve airflow with vents or fans, and open windows to let air circulate without leaving the garage door open.
- Manage humidity with a dehumidifier to help with moisture, odors and mold.
- Ventilate during the cooler early morning or evening hours.
- Consider an insulated garage door and insulated walls to reduce heat transfer year round.
- Choose lighter colors that reflect heat, and limit activities that add heat on hot days.
- Let a hot car cool outside for a while before parking it in the garage.
The garage and the rest of the home
Garage and house temperatures are connected. Better insulation and sealing in the garage can help the comfort and energy efficiency of the whole home.