This story shows you how to mend a wood sash.
A double-hung wood window typically has two sashes that move up and down. Many people nail and paint shut the upper sash. This makes it easier to seal but will make cleaning the window difficult if you cannot get at it from the outside.
If a sash will not stay up, the chain or cord connecting to the weight is probably broken. Replacing a chain or cord can be accomplished in an hour or so.
To make an older unit work more smoothly, a bit of detailed work is often required. If the window has been painted many times, you may need to scrape or even remove paint from sashes or stops in order to free the action. A balky pulley may also need to have its paint removed. Often a spray lubricant will help as well.
A drafty window can be sealed by adding weatherstripping. A storm window will help greatly as well.
Newer windows have a variety of mechanisms to keep sashes up when raised.
1 or 2 hours for most repairs
Screwdriver, hammer, utility knife, zipper tool, flat pry bar, tin snips, pliers, paint scraper, putty knife, taping blades, sanding block, chisel
No special skills
Place a drop cloth on the floor by the window.
Caulk, sash chain or cord, wire, spray lubricant, paraffin block or candle, finishing nails, perhaps repair parts for newer windows