Hey everyone, it’s Mia from the 70SD Steel Door and Window team here—today I’m chatting about something we get asked all the time: how well our 70SD steel windows hold up against UV rays. Let’s cut through the jargon, no fancy lab-speak that makes your eyes glaze over, just real, test-backed stuff you can actually use, especially if you’re shopping for windows that won’t fade, crack, or fall apart after a few Texas (or Arizona, or Florida, take your pick) summer bakes. 70SD Steel Door and Window
First, let’s get one thing straight: UV rays aren’t just sunburn stuff—they’re a window’s worst enemy, plain and simple. Over time, those invisible high-energy rays break down materials. For steel, people usually assume it’s indestructible, right? Wait—no, hold on. The steel itself is sturdy, but it’s not exposed raw. We use a coating system on our 70SD windows, and that’s the first line of defense. Cheap steel windows skip a proper coating, or use paint that chips in a year, then the steel starts to oxidize, and boom—you have rust, discoloration, and structural weakening before you know it.
Let me walk you through what makes our 70SD system different. We don’t just slap on a single layer of industrial paint. Our coating process is a 3-step pre-treatment + 2-layer powder coating system, baked at 200°C (that’s 392°F for us non-metric folks) in an industrial oven. Why does that matter? Powder coating is way more UV-resistant than wet paint—way less likely to chalk (that’s the dusty, powdery mess you get when paint breaks down) or fade. But the pre-treatment? That’s the secret sauce. We do a zinc phosphate wash first, which creates a rough surface for the powder to stick to, then a chromate-free conversion coating (we care about eco stuff too!) that acts as a barrier between the steel substrate and the top coat. No pre-treatment = coating peeling, full stop. We test every batch to make sure that adhesion is solid.
Now, the real test—how does this actually hold up to UV exposure? We don’t just trust the lab, even though we have a QUV weathering chamber on site that simulates 10 years of Florida sun in just 12 weeks. Last quarter, we pulled a window sample that had run through that chamber: no fading, no chalking, no coating blistering. Let’s put that in perspective for real life: if a window survives 12 weeks of accelerated UV, that’s about 10 years of direct, unfiltered sun—think west-facing windows in Phoenix, where the sun blazes for 12+ hours a day in summer. But wait, we’ve also had installers send us photos of 70SD windows we put up in Las Vegas 7 years ago, and they look almost identical to the day they were installed. That’s the stuff we care about, not just lab numbers.
But UV resistance isn’t just about the coating—wait, what about the other parts of the window? The frames, the seals, even the hardware? Let’s talk seals first. Most steel windows use EPDM rubber seals to keep air and water out, and guess what? EPDM can get brittle in UV light over time. Our 70SD seals are specially formulated with UV inhibitors—we don’t use the cheap, generic EPDM that cracks after 5 years. We tested ours in that same QUV chamber too; after 12 weeks, they still flexed like new, no brittleness at all. That means no drafts, no water leaks, even after decades of sun. The hardware? We use stainless steel or zinc-plated steel hardware, not the cheap plated stuff that can corrode in UV. Faded, rusted hardware makes a whole window look beat, so we made sure that’s not a problem.
Another thing we hear: “Wait, steel windows get hot in the sun, does that affect UV resistance?” Yeah, that’s a good point. Any metal window absorbs heat, which can speed up coating degradation if the coating isn’t formulated to handle heat. Our top powder coat is a thermally-stabilized polyester blend, specifically designed for exterior metal products. We tested it at 80°C (176°F) for 1,000 hours— that’s way hotter than any window will ever get in real life, even on a 110°F summer day. No discoloration, no change in coating flexibility. So even when the window is hot to the touch, the coating doesn’t break down faster.
Let’s compare that to what’s out there. I’ve had customers tell me they bought cheap steel windows from a big box store, same “70 series” label, but the coating started chalking after 2 years. Why? Because they cut corners on the coating process—only one layer, no proper pre-treatment, cheaper powder that isn’t UV-stabilized. Our 70SD system is built to avoid that. We don’t cut corners, because if your window fails in 5 years, that’s our bad, not yours.
Wait, let’s address a common myth: “UV resistance is only for dark colors.” No way. We do 20+ standard colors, from white and light gray to deep navy and black, and every single one of them gets the same UV-stabilized coating. White is actually a good test because it shows fading super easily—if a white window doesn’t yellow after 3 years, the coating is solid. We’ve had a residential customer in Houston who had our white 70SD windows installed 6 years ago, and when he compared them to his neighbor’s (non-70SD) white windows, his are still bright, the neighbor’s are yellowed to a cream. That’s concrete proof.
Now, what about long-term maintenance? You might be thinking, “Okay, it’s UV-resistant, but do I have to wax it every year?” Nah. The powder coat is self-cleaning to a degree—rain washes off dirt that would otherwise cause discoloration. The only maintenance we recommend is wiping it down with mild soap and water once a year, same as you would your car. No special treatments, no annual coats of paint, which saves you money over time. That’s a big plus for commercial buildings especially, where maintenance costs add up fast.
But let’s get real—no product is 100% UV-proof, right? Even the best coating will eventually show some signs of wear after 25+ years, but our 70SD system is designed to minimize that so you don’t have to deal with it for decades. We stand behind that, too—our 70SD windows come with a 10-year warranty that covers coating fading and chalking, which is way longer than most competitors’ warranties (some only do 2 or 5 years). That’s not a marketing gimmick, that’s us knowing our product holds up.
Who is this relevant for? If you’re a homeowner in a sunny climate, that’s obvious—you don’t want your windows to look old before your house’s paint fades. If you’re a commercial contractor building a strip mall or an office in Arizona or Florida, that’s huge—you need windows that won’t need replacing or repainting mid-way through a 15-year lease. Even if you’re building a rental property, these windows will be a selling point for tenants who don’t want to deal with drafty, faded windows.
I’ve seen so many customers pick windows based on just price, only to regret it a few years later when their windows look beat. At 70SD, we’re not here to sell you the cheapest window—we’re here to sell you a window that works, for decades, even in the harshest sun. The UV performance of our 70SD windows isn’t just a spec on a sheet—it’s the result of testing, attention to detail, and making sure every part of the window is built to last.
If you’re shopping for steel windows, whether for a new build or a retrofit, and you want to know more about how 70SD holds up to UV, or if you want samples or installation quotes, hit us up. We don’t do pushy sales stuff, just honest answers about our products.
Don’t get stuck with windows that fade, chalk, or rust after a few summers. 70SD steel windows are built for the sun.
Thermally Broken Steel Door and Window References:
- American Architectural Manufacturers Association. (2020). Standard Practice for Accelerated Weathering of Exterior Coatings for Metal Window and Door Products (AAMA 1405-20). AAMA.
- Steel Window Manufacturers Association. (2019). Design and Performance Guidelines for Exterior Steel Window Coatings. SWMA.
- National Fenestration Rating Council. (2021). UV Resistance Testing Protocols for Window Exterior Finishes. NFRC.
- Plastics Industry Association. (2022). UV Inhibitor Formulations for Elastomeric Seals in Exterior Building Applications. PIA.
PDA Steel Door Window Systems
PDA Steel Door Window Systems is one of the most professional 70sd steel door and window manufacturers and suppliers, also supports high quality customized service with low price. Please feel free to buy durable 70sd steel door and window in stock here from our factory. Also, pricelist is available.
Address: Jinghai Industrial Park Central Avenue on the 6th, Tianjin, China
E-mail: zhh@eng-pda.com
WebSite: https://www.pda-international.com/
