Jocobe, I think that you are misunderstanding the problem. The upper sash is not drifting, It stays up. The problem is that when the window is locked, there is still a gap. Balances have absolutely zero to do with this, as the materials have either shrunk, settled, etc to cause this as has been mentioned already. Bottom line: the windows are due for replacement. To fix it for now (until budget permits replacement): either add a thin piece of wood to the sill or head, or add additional weatherstripping to one or both. You can buy stick-on foam bulb seal in rolls from the store that would probably do the trick for a while. Shimming the lock/keeper would be another option. Ultimately, what you are trying to do is fill in the frame to take up the "slop" that is present when you move the sashes up and down when they are locked together.

If they are the sprial balances listed by NEEDWINDOWS then all you need to do is measure their lenght. The distance form the red or similar color plastic at the bottom to the top of the metal. Each sash has a left and a right - both the top and bottom sashes have two each. You need two tools to remove and install new balances. You need a phillips head screw driver (a screw gun is easiest) and a balance adjusting tool. The balance adjusting tool can be purchased from the balance supplier. They are usually not available in your local hardware or big box stores. After you recieve your new balances and are ready to replace the defective ones you'll have to first tilt in the bottom sash and then tilt the top sash right on top of it. Now all four balances should be exposed. Sometimes the balances are covered with a piece of vinyl trim, just take those off. The top of the balance is screwed to the vinyl. Look at the bottom of the balances and see how they are attached to the vinyl window shoes in the tracks. Practice using the balance tool by attaching it to the bottom two pins at the direct bottom of the balance. Hook the claws over these two pins, gently pull the balance out of the shoe with the tool attached and turn counter clockwise. Hold the tool tightly in your hands. if you feel tension on the tool then the balance is probably OK or may just need a turn or two to tighten itself up. Hook the balance back into the shoe. Check another one. If you feel no tension on the tool when you hook the pins and pull down a little then the balance either can be defective or just has to be re-wound. Sometimes it take 5 - 7 clockwise turns to start the balance to start tightening and pulling up. Don't over tighten it. Then it is time to re hook the balance into the shoe in the side track of the window. If you try to tighten the balance and you hear a clackety-clack, then the balance is broken. Replace it by unscrewing the screw at the top and installing the new one the same way. Remember to study how the balances are attached to the shoes before removing them so you know how to put them back. Since you said you are handy, with a little patience and some practice, you could repair them yourself. If it seems to be too difficult for you, contact your local replacement window dealer for help. Although he'll probably try to sell you all new windows, tell him you just want the ones you have repaired. Good Luck All The Best, The Porch Guy

I had single hung AL frame windows in a home I sold about a year and a half ago. they were ok, even though the house was a single story ranch going out side to wash the windows was a pain... some wiwdows were harder to reach from the ground and I still needed a ladder, plus some had flower beds outside under them. that made it harder since I didn't want to tramp down the flowers. I am starting to replace the old wood double hung windows with double hung windows that tilt in to clean. I really like them I have to say it makes cleaning them very easy and worth the price to me because I hate to clean windows so much. I have never cleaned the old windows in the house I am in now and doubt if I ever will clean any of the old windows before they get replaced since its such a hassle.

The reasoning behind this is the manufacturer doesn't make a good DH unit. The vinyl DH's need to be better built and stronger than the others. Anytime you have two fully functional sashes you require a more precise installation with more patience. The Single Hungs are just cheaper to make and easier to hang. Almost idiot proof in most cases. They are also more energy efficient from air infiltration becuase a lot of installers don't take the time to shim the DH unit properly. They end up leaking around the sashes, creating that ever so hated call back. With a stationary top sash they don't have to worry about anything leaking around the upper sash. The downfall of the SH is you can't tilt the sash in for cleaning. This can be quite trouble some for the windows off the ground a ways. There are ways around that for cleaning if shown the proper way. The history of the DH window goes back to the old farm houses that never had AC or Central Air. They would pull the top sash down about six inches and the lower sash up about six inches. This would let the air circulate better in each room by creating the drafting affect (Firefighters call it breathing during a house fire). With todays AC in almost every house the DH windows aren't really required for the drafting situation. You can still get them from almost every dealer. If they are balking at DH's with reasoning like they gave you. I would steer clear of them and start shopping for another supplier. Hope this makes sense to you. God Luck!!!