Estimate of u factor on old sliding door?

I’m replacing an old sliding door. It’s probably about 20 years old. Aluminum frame with no thermal break. Double pane window but likely no low-e coating and the seal is… I’m replacing an old sliding door. It’s probably about 20 years old. Aluminum frame with no thermal break. Double pane window but likely no low-e coating and the seal is…Read MoreGreenBuildingAdvisor