Here's What To Know About Buying New Sliding Glass Doors (& What To Watch Out For)

When it comes to adding natural light to a space by bringing the outside indoors, it's hard to beat a sliding glass door. These space-savers take up way less room than traditional hinged options, run along a low-profile track, and make it extremely easy to improve the airflow and ventilation in your home. Operated with a simple handle, a sliding glass door is a great option if you or a loved one has a difficult time grasping and turning a regular doorknob. Though they do require slightly more maintenance and may sometimes be more expensive than other models, they can also increase your home's value. And according to Ernesto Cappello, founder of Window Fix, Inc., if you're buying new sliding glass doors, it's important to focus on performance first and aesthetics last.

"As someone who's serviced over a million windows and doors across New York, I always urge clients to start with performance," Cappello told House Digest during an exclusive interview. "Before reaching for your wallet, ask: 'Can my existing sliding door be repaired to open, close, and lock as designed?'" he added. Repairs are far more budget-friendly than replacements, which average around $2,500. "Often, a sticky or drafty patio door can be restored with new rollers, tracks, locks, or weatherstripping, especially if it was well-built to begin with," Cappello said, noting that "a good technician should be able to assess this before you commit to a full replacement." But chilly drafts, cracked frames, and constant condensation are among the signs it's time to replace your sliding glass doors.

If you decide that repairing your sliding glass door isn't possible, there are important things you need to keep in mind before buying a new one. "If replacement is needed, the next critical question is: 'What type of property is this going into?'," Ernesto Cappello said during his exclusive interview with House Digest. He went on to explain that there are national performance standards for residential, light commercial, and architectural applications. Specifically, the American Architectural Manufacturing Association (AAMA) Performance Grade (PG) ratings can help you determine which sliding glass door is the best for your situation. "[These] standards dictate how well a door resists air, water, and structural pressure," Cappello said. "We recommend doors rated PG50 or higher, even for homes, because hurricanes, Nor'easters, and everyday use don't care about your ZIP code," he added.

Cappello also let us in on a little secret he said most sales reps probably won't share with you. "Sliding doors are designed to take in water into the bottom track, almost like a tank, and drain it out," the expert revealed. "If it doesn't have the right slope, drainage system, and sill design, it's going to fail." He recommended asking your sliding glass door manufacturer or sales rep to provide you with the air infiltration rate, the amount of water pressure the sill can handle, and the design pressure (DP) rating for the product you're considering. "Poor performance on any of these is a deal-breaker–especially if your patio faces wind or rain exposure," he added.

Once you've got the functional elements in place, then you can finalize your sliding glass door selection based on your preferred look. "Only after confirming performance, move onto aesthetics and sightlines," Ernesto Cappello said during his exclusive interview with House Digest. Along with picking a door that matches your home's architecture, he recommended carefully considering both energy performance. "Look for Low-E coatings, argon gas fills, and thermal breaks," Cappello suggested. You should also take a careful look at your hardware selection and make sure it balances form and function. "Operability and security are often overlooked, but critical," he warned.

When buying sliding glass doors, Cappello recommends prioritizing "performance, protection, and peace of mind." It can be tempting to focus on the sleekest frame, shiniest hardware, or what sliding glass door window treatments you should (or shouldn't) install. But the Window Fix founder emphasized that your choice should be driven as much, or more, by how your model will work under a variety of weather conditions as it is by how beautiful it looks. "Most homeowners shopping for a new sliding patio door focus on aesthetics, clean sightlines, narrow frames, sleek hardware," he said. "And while those details matter, they should come last, not first."