A picture window doesn't open, so there are no vulnerable seems or hinges that can wear out and fail. There is no weatherstripping that must be replaced to maintain peak energy performance. After we've installed the window, it is maintenance-free forever, aside from periodic cleaning.
Longer-lived windows are built on bulkier, heavier frames than typical windows, as they must be strong enough to stand up to the pressures created when a wall shifts and flexes from season to season. Most windows crack and leak after about 10 years; ours last generations.
The numbers are absolutely clear: we are selling the most efficient double-pane window you can buy.*
Glass pack: Energy Star 6.0
Window: Energy Star 6.0
NFRC Authorized Certification: Certified in all categories
* Testing performed by Keystone Certifications in 2016.