Hi.My home is 91 years old, and so are the window balances. Some need replacing. They are spiral and springy, and within a wooden channel in the windows
I think I've identified the parts I need to secure the balcances to the bottoms of my windows, but I'm unsure of the appropriate balance to buy. Will the 400 type work?
Thanks for your patience during this busy season. You weren't kidding: this is a very, very old spiral balance. Suffice to say they haven't made this exact model in a very long time, but you're on the right track. Modern spiral balances for non-tilt windows can usually be used as alternatives.
I personally like to go with the Series 500, along with a 17-012 bottom bracket to connect it to the sash. This is the same thing as the Series 400 that you already picked out but larger. I find that the larger, stronger Series 500 is better for wood windows, which tend to be heavy.
To determine what size you need, you'll have to measure the visible glass height and then do a little math. If this is for the bottom sash, you add 3" to the visible glass size. If it's the top sash, you only add 1".
So, for example, if your visible glass is 20" high, and if this is a bottom sash application, you'd want the S500-23. Does that make sense?
You'll also need the weight of your sash to determine the proper spring calibration. The Series 500 store page has a handy chart that tells you precisely how much weight each strength option supports.
Start by looking over the Series 500 and let me know if you had any questions. I'm more than happy to assist with anything you need to know.
