DOE & LBNL Data: How Window Attachments Save Energy in Your Home
Posted by The Window Place USA on Mar 17th 2026
Source: U.S. Department of Energy & Lawrence Berkeley National Laboratory. Energy Savings from Window Attachments. Retrieved from [https://www.energy.gov/sites/prod/files/2013/11/f5/energy_savings_from_windows_attachments.pdf](https://www.energy.gov/sites/prod/files/2013/11/f5/energy_savings_from_windows_attachments.pdf). Public domain.
The Science of Window Efficiency
When the U.S. Department of Energy (DOE) recommends adding window film to your home, they aren't just guessing. Their recommendations are backed by rigorous scientific modeling conducted by the Lawrence Berkeley National Laboratory (LBNL).
In a comprehensive 2013 study titled Energy Savings from Window Attachments, researchers set out to quantify exactly how much energy could be saved by retrofitting residential windows across various U.S. climate zones. Their findings provide the definitive, data-driven case for using surface-applied window films to lower utility bills and improve home comfort.
The LBNL Findings on Surface-Applied Films
The LBNL study analyzed dozens of different window attachments, from cellular shades to exterior awnings. A major category in their research was "surface-applied films" (both interior and exterior).
The researchers modeled these films on typical residential buildings across the North, Central, and South climate zones. Their key findings regarding window film include:
- Always Deployed: Unlike blinds or drapes, which must be manually opened and closed to be effective, the LBNL study noted that interior surface-applied films are "always fully deployed. This means that the film is applied to the window and remains there throughout all seasons" [1]. This guarantees continuous, passive energy savings without requiring any effort from the homeowner.
- Measurable Cooling Load Reduction: The modeling demonstrated that surface-applied films provide measurable energy savings, particularly by drastically reducing the cooling load in hot climates and during the summer months in mixed climates [1].
- Performance Tiers: The study categorized films by quality, noting that the highest-performing films (Quality A) feature highly reflective, low-emissivity (Low-E) properties that not only block summer heat but also retain winter warmth [1].
Beyond Energy: UV and Fade Protection
While the primary focus of the LBNL study was energy consumption (measured in site energy/GJ), the performance data used to calculate those savings also highlights the other major benefit of window film: UV rejection.
Because high-quality solar control films block up to 99% of ultraviolet radiation, the same film that reduces your cooling load is simultaneously protecting your interior furnishings from sun fading and protecting your family from indoor UV exposure.
Implementing the Science in Your Home
The LBNL data proves that retrofitting existing windows with surface-applied film is a scientifically validated method for reducing residential energy consumption. But you don't need a government grant to implement this technology in your own home.
By purchasing a supply-only roll of NFRC-rated solar control film, homeowners can easily replicate the energy savings modeled in the LBNL study. Because the film is applied directly to the flat glass, it is an ideal do-it-yourself project that eliminates the high cost of professional installation labor.
The Window Place USA: Data-Driven Efficiency
The Window Place USA supplies homeowners with the exact same high-performance window films analyzed by energy researchers. Stop guessing about your home's efficiency and start relying on proven science.
Upgrade your windows today with our easy-to-install, supply-only rolls. Contact us: inquiries@thewindowplaceusa.com | (866) 274-2769.
Frequently Asked Questions
Does window film really save energy?
Yes. Comprehensive modeling by the Lawrence Berkeley National Laboratory (LBNL) demonstrates that surface-applied window films provide measurable energy savings by reducing heating and cooling loads [1].
Do I have to open and close window film like blinds?
No. As the LBNL study notes, surface-applied films are "always fully deployed," meaning they provide continuous, passive energy savings 24/7 without any manual adjustment [1].
Can I get these energy savings by installing the film myself?
Yes. The energy savings are derived from the physical properties of the film itself. By purchasing a supply-only roll and installing it properly, you achieve the exact same performance as a contracted installation.
References
[1] U.S. Department of Energy & Lawrence Berkeley National Laboratory. "Energy Savings from Window Attachments." 2013. https://www.energy.gov/sites/prod/files/2013/11/f5/energy_savings_from_windows_attachments.pdf