Integrity by Marvin. LoE3-366 glass is now a glazing option for the maker’s windows and doors. The glass uses three layers of silver oxide to provide energy efficiency. Like other low-E coatings, LoE3-366 helps keep heat inside during the winter and outside during the summer, helping to lower homeowners’ energy bills. The glazing also has an improved U-factor and solar heat gain coefficient, both of which allow windows with LoE3-366 to meet standards for federal tax credits of 30% up to $1,500. 888.419.0076.