Windows in Pennsylvania have to face a freeze and a humid summer, but the opening itself depends on the house. Rowhouse windows sit in brick, often tall and double-hung, with a sill over a flat street and sometimes a unit blocking the sash all summer. Hill-house windows face a valley wind, rack in frames when the house has shifted a little, and include basement openings buried on the uphill side. Philadelphia rowhouses are not Pittsburgh houses on hills. Describe the opening, not a statewide window.
Some failures are repairs. Fogged glass, a broken balance, a sash painted shut. Some are the frame: a soft sill, a leak only when rain is blown at the brick, water staining the plaster under the stool. Insert work leaves the old frame. Full-frame work shows the rough edge, masonry in a row and a wall that may have been damp for years on a hill. Say how many openings and which rooms stay cold no matter what the radiator does.
Condensation is ordinary when these houses are closed up from fall through the freeze. Sweat on the inside of the glass is not a failed insulated unit. A fog between panes is. A hill house can add a frame that is out of square because the slope has tugged on the structure. A row can add a lintel or a brick joint above the window that is the real leak. Say if water shows up only in a wind-driven rain. Basement hoppers near a sidewalk or under a hill need their own sentence.
Have the material and the count. Wood, an older metal unit, or a later replacement, often mixed on one facade. Say whether any window must still open onto a fire escape or a rear yard. Ask how the sill sheds water and who patches trim. Odd sizes are common in both old cities. Do not promise yourself a stock unit. One worst opening, plainly described, starts the call.
A marble-stoop facade and a window looking down a set of city steps are not the same hole in the wall. Windows in Pennsylvania start with the house shape and the sash that failed. Call the number on this page.