Why Home Builders Love Low-E Windows (And Why You Should Too)

Why Low-E

The effect on the comfort level of a home’s occupants is one reason home builders like Low-E windows. Low-E has the ability to keep the temperature of the surface of the glass facing the interior very near that of the room itself, regardless of outside temperatures. For example if it is 0 degrees F outside, the inside surface of double pane glass can be as much as 30 degrees warmer than single pane glass but still 25 degrees lower than Low-E coated glass. The converse can be true during hot summer months. 

Another great reason for Low-E windows is energy efficiency. They are energy efficient because any material that reflects, absorbs, and emits radiant energy is going to save energy. Regular uncoated glass windows will take in heat during the day but release it right back out through the glass at night. This is why in some houses a room can be very hot during the day and freezing when the sun goes down. The result of this heat transfer is using our heating and cooling appliances more than we need to. No matter what type of Low-E windows you get, they will perform better than windows that have only clear glass.  

What is Low-E?

The ability of a material to radiate energy is known as emissivity. In general, highly reflective materials have a low emissivity and dull darker colored materials have a high emissivity. All materials, including windows, radiate heat in the form of long-wave, infrared energy depending on the emissivity and temperature of their surfaces. Radiant energy is one of the important ways heat transfer occurs with windows. Reducing the emissivity of one or more of the window glass surfaces improves a window’s insulating properties.

Low-e coatings have been developed to minimize the amount of ultraviolet and infrared light that can pass through glass without compromising the amount of visible light that is transmitted. Low-e glass has a microscopically thin, transparent coating – it is much thinner than a human hair – that reflects long-wave infrared energy (or heat). When the interior heat energy tries to escape to the colder outside during the winter, the low-e coating reflects the heat back to the inside, reducing the radiant heat loss through the glass. The reverse happens during the summer time.

 

What Low-E Is Not

Low-E is not the same as tinted glass. Tinting is the adding of alloying materials to the glass itself. Also, tinted glass tends to absorb sunlight and will get very hot when installed as a single pane, hence tinting does not improve insulating value.

The Future of Low-E

By changing the types of materials used in the ‘stack’ or layers of Low-E, or by increasing or decreasing the number of layers, we can now get more specific in choosing glass which will meet our exact project needs. Need high visible light but low U values? There’s a Low-E for that. Need greater protection from fading? There’s a Low-E for that. And it gets even more specific than that. Adding argon gas to the captive air space, as we all know, will improve insulating value. Adding various tinting agents to the glass itself will allow for even further refinement of the glass’s performance.

Is moving to a brand new home with Low-E windows and other high-end details on your mind? Contact The Boehmer Team. We can help.