Double-Hung Windows

Most people who type double-hung replacement windows Lehigh Valley into a search bar are replacing double-hungs that are already there. The style has been the default here for well over a century, from the brick rowhomes of center-city Allentown and the South Side of Bethlehem to the College Hill Victorians in Easton and the coal-era doubles stacked up the hillsides of Scranton and Wilkes-Barre. Those originals had rope-and-pulley balances, single glass, and a meeting rail never meant to hold back a February wind off South Mountain. What you buy today looks the same from the sidewalk and behaves very differently.

The modern double-hung earns its place through parts you never see: balances that hold a sash exactly where you leave it, an interlocking meeting rail that closes the old gap between the sashes, and compression weatherstripping at the head and sill. In a two-and-a-half-story twin with bedrooms tucked under a slate roof, those details separate a room that holds its heat overnight from one that needs a space heater running. The same parts keep humid August air outside, where a leaky meeting rail used to let it drift in all night.

Freeze-thaw writes the rest of the regional story. Old wood sills on a rowhome drink meltwater from the sidewalk side, swell, and split, which is why so many original sashes have been painted shut for decades. A replacement unit lands on a sill your matched installer has probed and, where needed, rebuilt, so the operation you get on the first day is the operation you keep. Tilt-in sashes finish the picture: on a street-facing second floor with nowhere to set a ladder, washing both sides of the glass from the bedroom is the feature owners mention first.

The glass does more work than the frame on a double-hung, because the sashes are the thin part of the wall. Two panes with a Low-E coating and an inert gas fill are the standard package, and a warm-edge spacer keeps frost from forming along the bottom rail in January. On a busy corridor, laminated glass in the street-facing units takes the edge off traffic noise.

Hardware decides how the window feels to live with. Wider sashes get two cam locks so the meeting rail pulls tight along its full width, and tilt latches should be large enough to pinch without fingernails. Screens come as half or full: a half screen sits outside the lower sash and disappears when the window is shut, while a full screen lets the top sash vent through it. If a heavier glass package is on the order, confirm the balances are rated for that sash weight.

Most Lehigh Valley double-hungs go in as inserts. Brick shelters the old frame on a rowhome or twin, so it is often sound and the new unit slides in with the interior trim and plaster untouched. Ask whether the hollow sash-weight pockets get packed with insulation, and how much glass you give up to a frame sitting inside the old one. Full-frame is the call when the sill has rotted through, when settling has racked the frame, or when the original was never flashed.

On the day, a crew of two typically works one opening at a time so the house is never open to the weather. The old sashes and stops come out, and the new unit is set, shimmed, foamed, and sealed before the crew moves on. Exterior wood brickmould is usually wrapped in color-matched capping. On homes built before 1978, federal lead-safe work rules apply, so ask how dust is contained.