Lastly, all of Milgard's Essence Series® products meet ENERGY STAR® v6 standards for U-Factor (how well the window insulates heat) and SHGC (how much solar radiations passes through the window). All the Essence Series® products feature argon gas insulation that helps guard against heat loss. Also standard are SunCoat® Low-e glass coatings that act as an insulator for certain non-visible wavelengths of light, keeping in warmth and preventing extra heat from escaping. Photo 2 of 4 in Sliding doors from The Window Series That Matches Performance, Appearance, and Ease-of-Use

Sliding doors

2 of 4

Lastly, all of Milgard's Essence Series® products meet ENERGY STAR® v6 standards for U-Factor (how well the window insulates heat) and SHGC (how much solar radiations passes through the window). All the Essence Series® products feature argon gas insulation that helps guard against heat loss. Also standard are SunCoat® Low-e glass coatings that act as an insulator for certain non-visible wavelengths of light, keeping in warmth and preventing extra heat from escaping.