I just recently purchased a home with aluminum Sliding windows. The windows dont seal anymore. The frames and windows are in good shape but the seals (glazing?) are worn and dried out to the point they have shrunk and no longer cover the whole surface to be sealed. Ive searched on google and several other places looking for these seals but have not been able to find them. Ive done my best to show what they look like below. Any help would be most apreciated.
Your best bet would be to get a bid on replacing the windows. You will save more in the long run on your energy bill. A replacement window will act as an insert and will be installed right over those aluminum frames that way the original waterproofing is not compromised.