Lightweight Quad-Pane Windows

Advances in film and thin-glass technology have made lightweight quad-pane windows a cost-effective alternative to typical double-pane windows.

Researchers from the National Renewable Energy Laboratory found 24% average HVAC savings compared to high-performing double-pane windows. View full-size infographic. [PDF - 296 KB]

GPG Findings 048, November 2021, Lightweight Quad-Pane Windows. Opportunity: Windows areresponsible for how muchenergy use? 34% OF COMMERCIAL BUILDING HVACENERGY IS LOST TO WINDOWS. An improved building envelope minimizes HVAC loads
and contributes to Net-Zero goals Technology: How are
Lightweight Quad-
Pane Windows
made? 4 PANES IN INSULATED
FIBERGLASS FRAME WITH WARM-EDGE SPACERS & KRYPTON GAS. R-8 RATED FULL-FRAME INSULATING VALUE
2 configurations: 2 outer panes of low-e glass containing
either 2 panes of thin glass or 2 layers of suspended film. Measurement and Verification. Where did M and V occur? NATIONAL RENEWABLE ENERGY LABORATORY (NREL) assessed quadpane
windows provided by Alpen High Performance Products at the Denver
Federal Center. One option used thin glass and one used suspended film. Results: How did
Lightweight Quad-
Pane Windows
perform in M&V? 24%
AVERAGE HVAC
SAVINGS compared to high-performance double-pane window
SUSPENDED-FILM
CONFIGURATION
SAVED 1% MORE
ENERGY THAN THIN
GLASS OPTION. HVAC
CAPITAL SAVINGS
REDUCES REQUIRED
SIZE OF HVAC
EQUIPMENT;
MODELING ESTIMATES
$120K IN EQUIPMENT
SAVINGS FOR A
498K SF BUILDING. SAME
INSTALLATION
IDENTICAL
THICKNESS,
COMPARABLE
WEIGHT, ~10% MORE
EXPENSIVE THAN
HIGH-PERFORMING
DOUBLE-PANE. Positive Return on Investment Across Climate Zones
Payback < 3 years at average GSA utility rates, $0.11/kWh and $7.43/MMBtu. Higher-efficiency windows can reduce HVAC capacity requirements and should be factored into the economics of any new construction or major renovation project. Deployment: Where does M&V
recommend
deploying
Lightweight Quad-
Pane Windows? ALL NEW CONSTRUCTION
END-OF-LIFE WINDOW REPLACEMENT
Thin-glass configuration is more cost-effective. Suspended-film version offers
versatility in low-e coatings, meets tempered glass requirements, and is about
1 lb lighter per square foot than the thin-glass configuration. [PDF - 296 KB]


Reference above to any specific commercial product, process or service does not constitute or imply its endorsement, recommendation or favoring by the United States Government or any agency thereof.

Last Reviewed: 2021-12-09