A closed garage in a Slidell summer can run far hotter than the outside air. The door is usually the biggest single surface facing the sun, and a thin, uninsulated steel door passes that heat straight inside. If the garage is a workshop, a gym, a laundry room or the way into the house, that heat follows you in.
Why does my garage get so hot?
Mostly through the door. A large, uninsulated steel door in direct sun heats up and radiates that heat into the garage, while gaps around the door let hot, humid air in. Many garages also have little or no ventilation, so the heat builds up through the day and stays.
A garage with a west-facing door takes the strongest afternoon sun. Roof and wall insulation matter too, but the door is often the easiest single improvement.
Does an insulated garage door make a difference?
Yes. An insulated door with a solid foam core slows heat moving through the door far more than a single sheet of steel. Insulated doors are also stiffer and quieter, and they usually seal better along the bottom and sides, which keeps humid air out.
When comparing doors, look at the R-value and at how the insulation is built. Injected polyurethane foam bonded between two steel skins insulates better, and stiffens the door more, than loose panels pressed into the back of a single-skin door. A new door also needs its springs matched to its weight, since an insulated door is heavier. See our page on new garage doors for what installation involves.
Can I just add insulation to my existing door?
You can, with a kit of foam panels cut to fit each section. It helps, but less than a door built with insulation, and it adds weight. The springs are set for the door's original weight, so a heavier door may need its springs adjusted afterwards.
How do I seal the gaps around a garage door?
Replace the bottom seal if it is flattened, cracked or torn, fit or renew the weather stripping along the sides and top, and check the seals between sections. A good test is to stand inside on a sunny day with the door closed: any light you can see is air getting in.
A door that does not close fully, or a bottom section that has bent, will defeat any seal. Those are repair jobs rather than weather stripping jobs.
Do windows and colour choice matter?
They do. Clear glass panels let in light but also heat, so in a garage that faces the afternoon sun, insulated or tinted glazing is the better choice. Lighter door colours reflect more sunlight than dark ones, and a dark door in full sun gets much hotter to the touch.
What else helps keep a garage cooler?
Ventilation. Gable or roof vents, a wall-mounted exhaust fan or a vent near the ceiling lets the hottest air escape instead of building up. Opening the door for a while in the cool of the early morning or late evening also flushes out stored heat.
Other steps that help:
- Park a hot car outside for a while before pulling it in after a drive
- Keep chemicals, paint and batteries off the wall that faces the sun
- Move the freezer or second fridge away from the door if you can
- Consider a wall-mounted opener, which frees the ceiling and allows ceiling insulation
Does Slidell's weather change what I should buy?
Slidell's heat, humidity and storm exposure mean a door here has to do more than keep heat out. Homes near the water in Eden Isles and Oak Harbor see salt air and wind, so a door with a protective finish and a wind rating suits them. Further inland, around Olde Towne Slidell or near Camp Salmen Nature Park, heat and humidity are the bigger concern.
An insulated, well-sealed door handles both: it keeps heat out in summer and holds up better under storm wind than a thin single-skin door.
Is it worth having the door checked before summer?
Yes. A door that is out of balance, has worn rollers or does not close fully lets in heat and humid air, and summer heat is hard on springs and seals. A seasonal check catches those faults before they cost you comfort.
If your garage is unbearable by midday, visit our Slidell page, see what a maintenance visit covers, or call Certified Garage Door at (985) 234-9130 for a free estimate on an insulated door.