I finally get to reply - one year later!
Thanks for the info, that is what I will get.
My window weighs 21#. Would I be better off with the 2840 stamp even though it is the next higher weight?
Would 2840 make the window lift easier?
Thanks
Thanks for posting! Good to hear from you again.
No, I recommend the 2830 option for a window that's 21 pounds. The window will not operate better with a stronger spring--in fact, it will be harder to close, and could cause damage to the sash itself.
No problem! Let me know if you have any other questions.