Paul, I double-checked the scale (it is a mechanical balance-beam scale that does "zero" out correctly) and it was still set at just over 36-3/4 pounds.
These windows are at my personal home and I can tell you that the sashes on these two have always felt too "heavy" for the balancers. Both windows are in our children's rooms and they always have had difficulty raising the sashes. It would seem to me that the sash weight being beyond the capacity of the balancers could be the cause of that. The lower sash is approx 50"w x 33" high with insulated glass (two panes).
I will wait to see what balancers you believe will be the best replacements. If you determine that the balancers should be up-sized, I should get two pairs and take care of the second window at the same time.
Thanks, Craig
Hi Craig,
That is a heavy sash.
I will email you a custom ordering link for the following, (4 each) S385-30 channel balance with 19-005 and 15-004 attached with stamp number 2965, this will carry a sash load of 35 through 39 pounds.
This information is based on 2 balances per sash. Balances are designed assuming friction in the jamb weather-strip will carry a portion of the sash weight. Suggested sash weights are approximate.