HR40 and Heat Mirror Technology

HR40 windows come packaged with Heat Mirror technology to keep your home feeling comfortable no matter the season.

Heat Mirror technology is an exclusive UV-blocking film that transforms regular windows to extraordinary windows.  It’s a high performing energy efficient glass technology that improves thermal insulation. It is extremely more efficient than a low-E coating on window panes. Low-e coatings are much more commonly used but have a thermal insulation performance of R-3 while Heat Mirror can perform up to R-10. Heat Mirror is heat reflective and provides the same thermal performance as five panes of glass with Low-E coating[1].

What Makes Heat Mirror Different? [2]

  • Heat Mirror® IG provides center-of-glass insulation performance ranging from R-7 to R-10
  • Blocks 99.5% of harmful UV rays
  • Offers superior winter heating and summer cooling due to its multi-cavity design
  • Reduces condensation buildup on the glass during winter
  • Weighs about 33% less than triple-pane glass

How does it all work?

Heat flow works in three basic ways, conduction, convection and radiation. Conduction is the way heat moves through things, convection is the way the heat circulates through gases and liquid (warm air is lighter so it rises, and cold air is denser so it sinks). Radiant heat, on the other hand, travels in a straight line and heats any solid thing in its path that absorbs the heat. Most insulation works by reducing conduction and convection. Reflective products reduce the radiant heat gain.

Heat goes to where there’s no heat, it attempts to resolve temperature differences by warming up cold areas[3]. What this means is, in the winter when you turn your heat on, it moves to warm up cooler areas, so when you have drafts or cold walls and windows, the heat flows to those areas to warm them up. If your window is inefficient then your heat basically flows to warm up the glass of your windows instead of staying in and warming up the desired room. During the summer, it works on a similar idea of heat from outside flowing towards indoors to warm up rooms because there’s a temperature difference. If you can feel the heat of the sun while standing in front of our windows, your windows are probably not working as efficiently as they should be.

The Heat Mirror technology works on the mechanism of radiant heat, by reflecting that radiant heat back into your home instead of seeping through the windows.


Now we know how heat works but what do the R-values mean? The resistance to conductive heat flow by insulating materials is measured in R-values also known as thermal resistance. The higher the R-value the higher the insulating effectiveness. So R-7 insulation is more effective than R-3.

This innovative window technology comes with a serious pedigree. It was used as part of the B2 Stealth Bomber. The stealth of the plane comes from the extremely low heat signature thanks to Heat Mirror film on the windows to radiate heat generated back into the cockpit and a liquid-cooled engine.

Its heat-reflecting properties are so revolutionary, Popular Science magazine named Heat Mirror® as one of the 100 greatest inventions of the last 1,000 years!

Heat Mirror is an advancement in window technology that not only helps hide the world’s best stealth plane but is also used to increase energy efficiency in the Empire state building[3]. You can bring that high-level technology to your home with the HR40 Window. Reduce your heating and cooling costs and keep your home comfortable.

Get your free estimate good for one year here.




The image came from