How To Replace A Double Pane Window Glass -

Total cost: $112 ($85 for the IGU, $27 for tools/sealant she didn’t already own). Time: 3 hours spread over two days (one to remove, one to install). A professional would have charged $450.

She brought the broken IGU to the glass shop. The tech measured it with a caliper. “This is 5/8 inch thick,” he said. “The measurement you wrote down was 3/4 inch. It wouldn’t have fit.” Sarah gulped. He cut a new unit to the exact thickness and size in 20 minutes. Lesson learned: Let the pros measure or confirm your numbers. how to replace a double pane window glass

Back home, she examined the window. On the interior side, she found thin vinyl or aluminum strips holding the glass in place—the glazing beads. She slid a stiff putty knife into the seam and gently pried. Snap! The first bead broke. She learned the hard way: start at the middle of the longest side, not the corner. The second bead came off cleanly. She labeled each piece (Top, Bottom, Left, Right) with masking tape. Total cost: $112 ($85 for the IGU, $27

Sarah’s first instinct was to run to the hardware store. Smartly, she stopped. She measured the entire window frame and took a photo of the manufacturer’s sticker on the spacer bar between the panes. She learned that for sealed double pane units, you don’t buy “glass.” You buy a sealed Insulated Glass Unit (IGU) —two panes fused together with a spacer. Her local glass shop cut custom IGUs for $85. She brought the broken IGU to the glass shop

With the beads off, the IGU fell inward. She caught it just in time. Underneath, she found old, rock-hard glazing putty and tiny plastic shims. Using a heat gun (on low!) and a chisel, she scraped the frame clean. “This is the worst part,” she muttered, picking dried putty out of her hair.

Sarah considered calling a pro—$400 minimum. Instead, she decided to try fixing it herself. Here’s what she learned through trial, error, and a few choice words.

Home again, she set the new IGU into the frame without sealant first. It slid in perfectly. She then inserted the plastic shims (bought for $3) at the bottom corners to lift the glass evenly. This prevents pressure points that cause future cracks.