If you’ve ever stood in front of a storefront on a sweltering summer afternoon and watched that aluminum door you installed last month pull just a little bit away from its frame, you know the small, confusing surprises heat can throw at metal. As an aluminum door supplier, I’ve spent years talking to contractors, building owners, and even homeowners who call panicking about “broken doors” that turn out to be nothing more than heat doing its work. It’s not a flaw in the aluminum itself—it’s just how metal interacts with temperature, and understanding that difference saves everyone a lot of headache. Aluminum Door
Let’s start with the basics, because that’s where so many people go wrong. Aluminum is a surprisingly efficient conductor of heat. Unlike wood, which warms slowly and holds onto heat for hours, or vinyl, which softens when it gets too hot, aluminum absorbs and releases heat fast. That means on a day when the outdoor temperature climbs to 95°F (35°C), the surface of an aluminum door can easily hit 120°F (49°C) in direct sun—even if the air temperature only feels warm. Compare that to a wooden door of the same size, which might top out at 90°F (32°C) under the same conditions, and you start to see why heat impacts aluminum differently.
The biggest and most common effect is thermal expansion. Almost every material expands when it gets hotter, and aluminum expands more than most construction materials you’ll find in doors. The math is straightforward: for every 1°F rise in temperature, aluminum grows by about 0.000013 inches per inch of length. That might sound tiny, but let’s put it in perspective. A standard 80-inch tall aluminum door will expand by roughly 0.01 inches for every 10°F change. If that door goes from a cool 60°F (15°C) installation day to a 100°F (38°C) summer day, that’s a 40°F difference, so total expansion is about 0.04 inches. That’s not much, but if your door is sealed tightly into its frame with no room to move, that extra 0.04 inches can make the door stick, refuse to close, or even warp slightly if the pressure is uneven.
Wait, warp? Yes, that’s another common issue. Aluminum is strong, but it’s also lightweight and thin compared to other building materials. If one side of the door is in direct sun and the other is in shade, the sun-facing side will expand faster than the shaded side. That uneven expansion creates stress, and when stress builds up over time, it can cause the door to bend or curve—what builders call “thermal bowing.” I’ve seen this on storefront doors that get half a day of sun on the west side of a building; by mid-afternoon, the top of the door pulls 1/8 inch away from the frame on the shaded east side. It’s not a permanent flaw if you adjust for it, but if the door was installed with too little clearance, it will rub, make noise, and even wear out the hinges faster.
Another thing I warn customers about is how heat affects any finishes or hardware attached to aluminum. Most aluminum doors are anodized or powder-coated to protect them from corrosion, but extreme heat can break down those finishes over time. For example, a powder-coat finish that works fine in mild climates can fade or crack if the door is exposed to constant high heat—like a door on a south-facing facade with no awning or overhang. Heat also affects hardware: brass or steel handles, locks, and hinges expand at different rates than aluminum. If the handle is steel, it will expand less than the aluminum door, so as temperatures rise, the handle might feel loose, or the screw holes might strip because the metal shifts unevenly. That’s why we always recommend using hardware that’s engineered to match aluminum’s expansion rate, or leaving extra space around hardware when installing the door.
I get asked a lot: is aluminum too hot to use in hot climates? The short answer is no, but it needs to be designed with heat in mind. Cheap, thin aluminum doors from unknown suppliers are the ones that have issues with warping and sticking when it’s hot. The aluminum doors we supply are made with 1/8-inch thick aluminum (or thicker for commercial applications) and have reinforced frames with slots that let the door expand without pressing against the frame. We also add thermal breaks to commercial doors—insulating strips that separate the exterior aluminum from the interior, so the heat doesn’t transfer inside as fast. That’s a game-changer for places like Arizona or Florida, where summer temperatures stay above 90°F for months on end. A door with a thermal break stays cool to the touch on the inside, prevents the air conditioning from working overtime, and cuts down on the expansion stress that causes sticking.
Let’s talk about a real example from last summer. We supplied a set of aluminum storefront doors to a small retail shop in Phoenix that had a problem the previous year: their old aluminum doors would stick so bad in July that employees would have to pry them open in the afternoon. The contractor who installed the old doors had used regular aluminum, no thermal breaks, and installed them with only 1/32 inch of clearance around the frame—way too little for expansion. This time, we supplied doors with 1/4-inch clearance around the frame, thermal breaks, and a heavier gauge aluminum. In August, the store manager texted me a photo of the door open in the 105°F (40°C) heat, with no sticking at all. That’s the difference between understanding how heat interacts with aluminum and guessing.
Heat isn’t just a summer problem, either. Many people forget that aluminum contracts when it gets cold. That 0.000013 inches per inch works in reverse: when temperatures drop, the door shrinks, which can make gaps around the frame bigger, let in drafts, or even cause hardware to come loose. It’s a balance—your door has to have enough clearance to expand in heat, but not so much that it’s drafty in the cold. That’s why we work with every customer to measure the average temperature swings in their location and adjust the clearance accordingly. For a place with moderate temperatures, we might use 1/16 inch of clearance; for a desert climate with 40°F daily swings, we go up to 1/4 inch.
Another common myth: “aluminum corrodes in heat.” That’s not entirely true. Aluminum actually forms a natural oxide layer when it’s exposed to air, which protects it from corrosion. But that oxide layer can be damaged by extreme heat combined with salt or chemicals—like salt air near the ocean, or industrial chemicals in a factory. In those cases, the oxide layer can break down faster when temperatures are high, leading to pitting. That’s why we offer corrosion-resistant coatings for doors in coastal or industrial areas, and we make sure the aluminum is treated to withstand the specific temperature and environmental conditions of the customer’s site.
So what does all this mean if you’re choosing an aluminum door for your home or business? First, don’t assume all aluminum doors are the same. A cheap door from a big box store might be thin, have no thermal break, and be installed with too little clearance, leading to problems when it gets hot. The doors we supply are tested to withstand temperature swings of up to 120°F (49°C) without warping or sticking. Second, tell your supplier about your climate. If you’re in a hot, dry place, you’ll want a thicker gauge aluminum and thermal breaks. If you’re near the ocean, you’ll need a corrosion-resistant finish. Third, make sure your installer understands thermal expansion. Even the best door will have issues if it’s installed with no room to move.
Here’s the thing: heat is never going away, and aluminum is still one of the best materials for doors, because it’s strong, lightweight, low-maintenance, and recyclable. The key is designing the door to work with heat, not against it. I’ve been in this business for 12 years, and I’ve seen every mistake you can make with aluminum doors in hot weather. That’s why we don’t just sell a door—we work with customers to figure out their specific needs, explain how heat will affect their door, and make sure they get a product that works year-round.
If you’re planning a project and want to make sure your aluminum door handles whatever the heat throws at it, don’t guess. Reach out to us to discuss your requirements. We’ll walk you through the science, show you the right options for your climate, and make sure your door works as well in the middle of summer as it does in winter. Don’t let heat turn your door from a simple part of your building into a headache—let’s get it right the first time.
Aluminum Panel References
- ASM International. Properties of Aluminum Alloys: Thermal Expansion. ASM Handbook, Volume 2: Properties and Selection: Nonferrous Alloys and Special-Purpose Materials. 1990.
- American Architectural Manufacturers Association (AAMA). Thermal Performance of Aluminum Doors and Windows. AAMA 1503-19. 2019.
- National Institute of Building Sciences. Building Physics: Thermal Expansion in Building Materials. 2021.
- Aluminum Association. Aluminum in Construction: Design Guidelines for Thermal Performance. 2020.
Zhejiang Jusen Building Materials Technology Co., Ltd.
Address: No.7, Tongyuan Shiquan Industrial Park, Haiyan County, Jiaxing City, Zhejiang Province
E-mail: sales@jusenzj.com
WebSite: https://www.honeycomb-js.com/
