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

HR40 bay windows, Middletown CT

Krypton vs. Argon Gas

It’s time to get your windows replaced, and there are so many options on the market from big name brands to local contractors. But when it comes to deciding on which windows should replace your old ones, energy efficiency plays a big factor in your decision.

To increase the efficiency of replacement windows, most windows on the market have upgraded from single pane windows to double pane filled with one of two gasses – argon and krypton. Both Argon and Krypton are odorless, colorless and non-toxic inert gasses that increase insulation and energy efficiency safely[1]. Gases work by preventing heat from escaping between the panes of glass, helping keep the house warmer in the winter.

The most common filling for double pane windows is low E argon gas. Argon gas helps make the window better insulated to keep summer heat out and winter heating in your home. Gas has become a norm in window insulation because gas is denser than air making it more thermally efficient than windows not filled with gas. Argon is six times denser than air, meaning it slows down the thermal energy traveling through the window.  Krypton is six times denser than Argon and twelve times denser than air.  This makes it more efficient at slowing down or blocking thermal energy than Argon.

Argon is a cheaper alternative to Krypton gas so it has become the norm for window companies. Even as the norm, it doesn’t deliver the same efficiency rating. Even though you might be paying less, you’ll end up paying more in energy losses.

How is Krypton more effective?

The particles of Krypton gas are smaller than argon particles[2]. As a result, Krypton particles fit better into smaller spaces and crevices.  All nooks and crannies get filled up. less room for heat to pass through.

You deserve better than the norm. However, it can be hard to find better when everyone seems to be selling the same stuff. The exclusive HR40 windows, however, uses krypton gas filling instead of argon. The HR40 windows differentiate in many other ways from the typical windows on the market.  They’re one of the most energy efficient, reliable and low maintenance windows out there. You can read about the other differences here.

You can experience the difference for yourself with a free estimate good for one year on HR40 windows.