We often talk about low-E glass and how it’s the best long-term energy-saving option for your home. But most people don’t know the science behind this smart glass. People often ask us how low-E glass can block heat in the summer months, while simultaneously retaining it in the winter. Today, our very own Bill is going to demonstrate how it all works.


Hi, it’s Bill from Window World of Little Rock! Today we’re going to show you a mechanism that demonstrates the benefits of low-E glass or low emissivity body glass. In this box, we have four different types of glass: single pane glass, double pane insulated glass, and two different types of low-E or low emissivity glass. We’re going to use a radiometer, which measures radiant heat, and a 250-watt heat lamp.

Low-E Glass with Argon Gas

The first glass we are demonstrating is low-E glass with argon gas. First, I’m going to turn this 250-watt heat lamp on and put the radiometer right up to the glass. As you can see, the radiometer is actually moving backwards. If there were radiant heat coming through the glass, it would make that radiometer spin. Right now, it’s barely moving.

Clear Insulated Glass

We’re going to now try the clear insulated glass, not even single pane, and roll the radiometer up to the glass and watch it start to spin. What it’s showing you is radiant heat coming through the glass. Glass is a conductor of heat and cold, which comes into your home. 

Low-E Glass

Now we’re going to go back to the low E glass. I’m going to stop the radiometer and then put it back up to the glass, and now it’s actually rolling backwards. Of course, you can’t feel the heat, but the radiometer shows you that the low E glass is working. 

Single Pane Glass

Next, let’s go to single pane glass. Watch the single pane glass. You can probably feel the heat coming through the camera, can’t you? I sure can. That’s what low emissivity glass does for you, and it will change everything in your home. It will lower your operating costs by at least 30%. It’ll keep you warmer in winter, cooler in the summer, and lower your overall operating costs. Low-E glass is a no brainer.

If you’re looking for energy-efficient, affordable windows with low-E glass, give us a call today