Alpine Window Missing Balances

This is indeed a tricky situation, but we still may be able to help. First off, are there any identical-sized windows in the house with the balances still intact? If so, going off them would probably be a safe bet. If not, is there at least a similar window in the house that still has the balances? If so, please remove them and show us the fittings on either end--that will at least help us narrow down the kind of balances you're working with. The Alpine brand isn't associated with any specific kind of channel balance, so I'm afraid we can't go off manufacturer information alone. 

Next, is this a non-tilt window (i.e. it can't be tilted in for cleaning)? If so, please tell me the height of visible glass in the window sash. Also, please give me the exact weight of the window sash. This needs to be precise as possible. That, along with the other information asked for, would be a huge help. 

Thank you for this information, that is very helpful. Based on your description of your Alpine window, the visible glass height at 20.5" and weight at 12.3 lbs., I think our S385-22 channel balance with a 2130 stamp will work for you. The 2130 will hold a sash weight of 12 through 15 lbs.