Cathedral ceiling with windows to a beautiful view

From planning and design to construction and materials, we'll walk you through every step of the process to help you replace your windows.

Step 8: Energy Efficient Glass Options

Low-E

Low-E is an invisible coating on the glass that is designed to reflect heat both entering and exiting your home, so it helps your windows perform their best in all seasons.

The low e difference infographic

Low-E Glass Windows Overview

Gas Fills

Gas fills are special gases pumped inside insulated glass units (double and triple-paned window assemblies also known as IGUs) to improve their thermal efficiency. These vicious, slow-moving gases (typically, argon and krypton) allow for less convection than would ordinary air, minimizing convective currents within the window and reducing the transfer of heat across the window.

Argon, which comprises slightly less than 1% of the Earth’s atmosphere, is non-toxic, inert, clear and odorless. Its thermal conductivity is roughly 67% that of air and it’s inexpensive, making it an attractive gas fill.

Krypton shares many qualities with its fellow noble gas argon, except that it’s an even better insulator, albeit more expensive to produce. When cost and functionality are considered, argon is a more efficient thermal barrier per dollar spent, especially in the larger ½-inch (11mm to 13mm) gaps between double-paned windows.

Krypton gas fill infographic

Dual or Triple Glaze:

Most window manufacturers offer 2 or 3 panes of glass in their sealed units. Dual glaze is the most popular option as it is cost effective, and when combined with a Low-E coating, or gas fill, can be very energy efficient. Triple glazed units go above and beyond, offering not only better performance ratings, they also reduce the noise transmission between outside and inside.