A stuck window is just the kind of problem that you may not even be conscious of until a solution is pressing: Either you need to open the window for ventilation, or cold weather or rain imply you must shut that window instantly. Everything from paint to a house that is settling can cause that window to stick. On the other hand, the solutions you want to fix the problem are probably already on hand.
A Hairy Situation
Humidity has the exact same impact on a few wood-framed windows as it does on hair: flux produces the window uncontrollable. The solution for this problem also comes with a hair-related solution: a hair dryer. If the window timber has swelled and put the window to an immobile place, objective a hairdryer set to reduced heat at the sash along the window frame on either side till the swelling has decreased slightly. Wiggle the window a little until it is free of charge.
Oops, It’s Coated in Paint
If a window frame is painted in haste, rather than its parts being painted separately to avoid sticking, then it is possible that paint sealed that window shut. Gently slide a craft knife or utility knife between the window sash and the stop — the vertical trim piece on either side — to split the paint free. It’s possible the paint problem is about the exterior, so check the outside as well, if you can. Use care not to affect the timber itself, if managing timber, as some timber is soft enough to become dented or cut in this procedure. If this occurs, sand these areas gently with a fine-grit sanding block.
It’s Truly Stuck
If the window is stuck and paint doesn’t appear to be the culprit, you might need to resort to more aggressive steps. First, remove the stops along all sides of the window indoors by prying them loose or unscrewing them. Wiggle the window to find out whether it will move; this might be all that is required. When it’s still stuck, then tap on a thin chisel or putty knife with a mallet across the bottom edge of the window outside, or inside if you do not have access to the exterior of this window. Repeat the procedure along the faces of the window as well, if the window still doesn’t move.
If that window stuck after, there’s a good chance it’ll stick again, especially if it’s a vintage wood window in an old home. Smooth any burrs, snags or splinters along the tracks the window fits in to having a sanding block. A sanding block flexes to contours, making it perfect for this use. Rub the smoothed surface down with wax to help the window glide better; perform this together with the window in the closed and open positions to coat the whole track.