NREL's 2024 Study Confirms: Window Film Delivers Measurable Energy Savings Across All U.S. Climate Zones
Mar 16th 2026
Source: National Renewable Energy Laboratory. (2024). End-Use Savings Shapes: Measure Documentation — Window Film (NREL/TP-5500-86554). U.S. Department of Energy. Public domain.
The Most Current Federal Research on Window Film Energy Performance
In 2024, the National Renewable Energy Laboratory (NREL) published the most current federal documentation of window film energy savings available anywhere. The study, "End-Use Savings Shapes: Measure Documentation — Window Film" (NREL/TP-5500-86554), provides standardized energy savings data used by utilities, state energy offices, and the DOE itself for energy modeling and program planning.
What NREL Found: Window Film Significantly Reduces Solar Heat Gain
The study's core finding is unambiguous. Window films "significantly reduced the solar heat gain coefficient (SHGC) of the overall glazing system."[3] NREL modeled window film performance across all U.S. climate zones:
| Climate Zone | States | Window Film Performance |
|---|---|---|
| Zone 1–2 (Hot-Humid) | FL, TX, LA, MS, AL, HI | Highest savings — cooling season dominates |
| Zone 3 (Warm-Humid) | GA, SC, NC, VA, AR, OK, NM, AZ, CA (coastal) | High savings — strong cooling season |
| Zone 4–5 (Mixed) | MD, DC, MO, TN, CO, OR, WA, PA, OH | Moderate savings — year-round benefit with Low-E film |
| Zone 6–7 (Cold) | MN, WI, MI, NY, ME, MT, ND | Lower but positive savings — Low-E film recommended |
Why This Study Matters: The DOE Uses This Data
The End-Use Savings Shapes project is used by electric utilities when designing demand-side management programs, state energy offices when calculating building retrofit savings, and the U.S. Department of Energy when modeling national energy savings potential. When NREL documents that window film "significantly reduced SHGC," that language carries weight across the entire U.S. energy efficiency ecosystem.
Window Film as a Passive Retrofit: No Mechanical Systems Required
One of the key advantages documented in the NREL study is window film's classification as a passive retrofit solution — no electrical connection, no moving parts, no maintenance, no structural modifications, and no disruption to building operations during installation.
Solar Gard: NREL-Performance-Class Window Film
The Window Place USA supplies the full Solar Gard professional product line — the same class of spectrally-selective and Low-E window films modeled in NREL's 2024 study.
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Frequently Asked Questions
Where can I find the full NREL 2024 window film study?
The full study is publicly available at: https://docs.nrel.gov/docs/fy24osti/86554.pdf. It is a U.S. Government work in the public domain.
Does window film qualify for utility rebates?
Many utilities offer rebates for window film installation based on documented energy savings. The NREL End-Use Savings Shapes data is the standard reference used by utilities to calculate rebate amounts.
What climate zone is my building in?
The DOE's climate zone map is available at energy.gov. Most of the southern United States is in Zones 1–3 (highest solar control film savings). The Mid-Atlantic, Midwest, and Pacific Northwest are in Zones 4–5 (best served by Low-E film).
[3] National Renewable Energy Laboratory. (2024). End-Use Savings Shapes: Measure Documentation — Window Film (NREL/TP-5500-86554). Retrieved from https://docs.nrel.gov/docs/fy24osti/86554.pdf. U.S. Government work, public domain under 17 U.S.C. § 105.