Insulated Glass Garage Doors R-Value (What Makes It Important?)

Glass Garage Doors are not without drawbacks but their elegance is a perfect match to modern contemporary architectural style. You just have to have them! Even if your home faces really cold winters. So, Can Glass Garage Doors Be Insulated? And What Makes Insulated Glass Garage Doors R-Value Important?

Glass Garage Doors use Tempered Glass. They can be insulated by using Insulated Glass instead. R-Value is a measure of the “resistance to heat flow”. So the Insulated Glass Garage Doors R-Value gives you an idea of how well your garage door will be able to handle the cold winters.

Let me get into more detail so that you have a better understanding.

How do you Insulate a Glass Garage Door?

Steel is the most popular material used to make garage doors. Steel is a good conductor of heat. So steel garage doors need to be insulated to save energy costs. 

Steel garage doors can be insulated easily because they are opaque.

You can either stick the insulation panels on the interior of the steel garage door, or better still, sandwich it between two sheets of steel.

Glass, just like steel, is a good conductor of heat too.

But how do you insulate a glass garage door that is transparent?

This is the challenge!

Insulated Glass Garage Doors R-Value
PHOTO CREDIT: WAYNE DALTON

Before I answer this question, I believe I should explain about R-Value.

What is the R-Value of a Garage Door?

R-Value is a measure of the “resistance to heat flow”. The higher the R-Value, greater is the “resistance to heat flow”. 

Heat behaves just like water. Water flows from a higher level to a lower level. Similarly heat flows from a higher temperature level to a lower temperature level. From the warmth of your garage to the cold outdoors in winter.

R-Value is a very important parameter to consider in the context of Garage Door Insulation. R-Value is a measure of the effectiveness of insulation.

The higher the R-Value the better is the insulation. But there is more to it than that.

  • R-Value is a measure of the heat flow through conduction only. It does not take into account heat losses through radiation or convection.
  • R-Value as a measure is relevant for an element of the building such as a Garage Door, not just specific materials such as steel or glass.
  • A doubling of R-Value does not mean that the heat flow has reduced to half. For example, R-16 offers a 5% reduction in heat flow as compared to R-8, not 50%. That is, doubling of the R-Value reduces heat flow by 5%, not 50%.

What is Insulated Glass?

Steel is insulated by sandwiching insulating material such as polystyrene foam between two sheets of steel.

In the case of glass, the insulating material must insulate but allow light to pass through. This is achieved by sandwiching air, an insulating gas (such as Argon or Krypton) or vacuum between two panes of glass.

Insulated Glass Unit (IGU), which uses Argon or Krypton, form the glass panels used in Insulated Glass Garage Doors.

Argon gas is heavier than air, colorless, odorless, nonflammable, nontoxic and inert. It is also completely safe for humans & animals.

Insulated Glass

Krypton has even better thermal performance than Argon. Krypton is more expensive and is used in triple layer insulated glass panels.

Insulated Glass Unit (IGU) also has a coating of an invisible, low emission (LowE) material. LowE blocks a significant part of the infrared radiation (IR) from the sun.

What is the R-value of Insulated Glass?

The R-Value of Insulated Glass depends on the glazing, the number of glass panes and the gas fill used. The Table below has the information.

Number of PanesGlazeGas FillU-factorR-Value
Single PaneClear1.01.0
Double PaneClearAir0.52.0
Double PaneLowEArgon0.254.0
Triple PaneLowEArgon0.205.0
Triple PaneLowEKrypton0.157.0

Note: U-factor is a measure of “loss of heat” while R-Value is a measure of “resistance to heat flow”.

What is the R-Value of a Glass Garage Door?

Many reputed manufacturers offer Insulated Glass Garage Doors with an option to select the R-Value. For example Model 8850 from Wayne Dalton gives you the choice of:

Glass Type &
Door Construction
R-Value of
Insulated Glass
R-Value of 
16X8 Door
½” insulated glass
PU filled rails & stiles
1.752.74
½” insulated glass Low E
PU filled rails & stiles
2.383.30
½” insulated glass SolarBan 70XL
argon filled
3.1253.96

Are Insulated Glass Garage Doors More Expensive?

A decent quality glass garage door is more expensive than a standard steel garage door for example. The glass used must be tempered glass for safety & security. It needs to be thick so that it can withstand wind load and burglary attempts.

According to HomeServe, the common glass garage door styles and their respective costs are:

  • French Garage Doors: $1,500-$5,000
  • Carriage Garage Doors: $1,100-$3,900
  • Paneled Garage Doors: $900-$2,000

Insulated Glass Garage Doors will add another $800-$2300 to the cost.

The installation cost is also higher than standard garage doors as glass garage doors are heavier. The installation cost may be around $200 for a single door and $400 for a double door.

If you are considering installing an insulated glass garage door, aesthetics, not cost, should be your main concern. A glass garage door will not let you down!

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Thank you very much for reading the post. I do hope you found it informative and useful.

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