Windows in Maryland take humidity, winter drafts, and, near the bay, salt that works on frames and hardware. A mountain house loses heat all winter through old sash and thin glass. A Piedmont house swells wood and fogs panes from late spring onward. A Shore house adds corrosion and wind-driven rain at the sill. The same window line does not belong in all three places. Describe the opening you actually have, and name the wall that takes the weather, because that wall fails first.
Older houses across the state often still have wood sash, sometimes painted shut, with cords and weights that quit long ago. Newer suburbs are full of insulated units whose seals have turned the glass milky. Those are different repairs. A clouded pane can sometimes be replaced without tearing the frame apart. A rotten sill cannot.
How the window sits in the wall matters more than any brochure. Brick openings, old wood frames, and later inserts each shed water in their own way. If the stain is on the trim and the glass is intact, a new pane will not stop the leak. Storm rain on the Shore and meltwater on western sills both show up at that joint between frame and wall. Say which floor and which direction the opening faces.
You do not need a full count of every window before you call. Say whether the trouble is one room, the weather side, or the whole house. Mention original trim you want left in place, a bedroom on a loud road, or a bath window that sweats all summer. Stuck locks, failed balances, and screens that no longer sit in the channel are fair to raise if they are the real problem.
Look at the sill from inside before you call. Soft wood, a dark corner, and water on the stool change the job. Windows in Maryland fail from the climate as often as they fail from age, and the climate depends on whether you face a ridge, a suburban tree line, or open bay wind. Bring the wall, the material, and the symptom. Call the number on this page.