R5 Triple Pane Windows and Patio Doors

R5 insulation rating = U-value .20

R5 is Eco-Friendly Energy Efficiency

Common Energy Star windows and patio doors only have an R rating of 3. We designed a series with an R rating of 5 for the ultimate in energy efficiency.

How Much Difference Does an Energy Efficient Window Make?

Heat and cold transfer through windows causes approximately 30% of heating and cooling energy costs nationally. That is an annual 4.31 quadrillion BTU of energy consumption.

R5 = U-Value .20

U-value is the rate of heat flow through a window; the lower the value, the better the insulating quality. Most commonly the U-value is used to measure a window's total insulating value. R-value is the resistance of a material to heat flow; the higher this number, the better the insulating value.


  • Reduced heat loss in the winter, better than typical Energy Star or Low-E windows
  • Potential for significant reduction in energy costs
  • Moderate to significant reduction in noise levels compared to double pane windows


  • Triple-Glazed: the insulated glass unit on an R5 window has three panes of glass
  • Krypton Gas Filled Between the Panes: Krypton has significantly better insulating qualities than Argon
  • Double Low-E glass: Low-E is on the exterior pane and the interior pane

Lang Windows and Patio Doors with the R5 Upgrade

R5 is available on all Lang vinyl windows and patio doors, except Rezilience:

Platinum Series
Powerweld Series
Renaissance Series
Glide Patio Doors (Vinyl)


* Technical information was provided by a third-party testing laboratory. Lang makes no representations or warranties as to the accuracy or completeness of such information. These statements are for informational purposes only, and may differ from actual results. Accordingly, Lang is in no way responsible or liable for any claims, damages, losses, costs or expenses of whatever kind that may result from the above.