If you’re shopping for new windows, you’ve probably heard the term “Low E.” So, what are Low E windows? Here is the simplest definition: Low-Emittance, or Low-E, is a razor-thin, colorless, non-toxic coating applied to window glass to improve energy efficiency. Low E windows are totally safe and are becoming the standard for energy efficiency in the modern home.


1. Reduces Energy Costs

Low E applied to windows helps block infrared light from penetrating the glass from the outside. Room side Low E applied to the interior pane keeps in heating/cooling energy. Bottom-line: Low E windows are much more energy efficient, helping you save on heating and cooling costs.

2. Reduces Destructive UV Rays

Low E windows help reduce ultraviolet (UV) light. UV light waves are the ones that over time will fade color on fabrics and you probably have felt them at the beach (burning your skin). Blocking UV rays save your carpets, furniture, drapes, and floors from fading and sun damage.

3. Does Not Block Natural Light

Yes, Low E windows block infrared light and UV light, but one other vital component makes up the solar spectrum, visible light. Of course, they will reduce visible light compared to a clear glass pane, but Low E is not a blackout. Plenty of natural light will brighten your room.  Because if it didn’t, you might as well just make that window a wall.

Not all Low E windows are the same

By combining Low E with double/triple panes of glass (also referred to as double or triple glazing) and insulating gas fills such as Argon or Krypton, you increase the energy efficiency even more. Learn more about What Makes Windows Energy Efficient. And remember to cater your window decisions around your climate zone.

Also, if receiving tons of natural light is essential to you, be sure to ask about a window’s visible transmittance (VT) rating. This rating should be readily available for any window your considering.

If you’re ready to talk to a contractor about the type of windows you need, visit HBP ProZone to find, compare, and get quotes from experienced professionals in your area.

Additional Resource

There’s a whole lot of stimulating science behind Low-E and how it works, so if you’re looking to nerd-out you can satisfy your thirst for super in-depth Low-E knowledge by visiting the Vitro Glass Education Center.

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