The EcoTherm 4000 line unites elegance and performance in a single, highly-efficient system. Engineered for strength and durability, with high-end features typically found only in the most expensive premium lines, the 4000 vinyl replacement window delivers superior value.
|HP Low E||0.32||3.13||0.29||0.54|
|Supra Low E Argon||0.28||3.57||0.28||0.54|
|DOE R5 Triple Glass Package||0.19||5.26||0.22||0.41|