Ecolux 70 Low-E Window Film: The DOE-Recommended Solution for Year-Round Energy Savings in Mixed Climates

For buildings in mixed climates — states like Virginia, Maryland, Missouri, Tennessee, Colorado, and the Pacific Northwest — energy efficiency is a year-round challenge. Summers bring intense solar heat gain that drives up cooling costs. Winters bring heat loss through cold glass that drives up heating costs. Standard solar control films solve the summer problem but can slightly reduce beneficial solar heat gain in winter.

The solution is Low-E (low-emissivity) window film — and the U.S. Department of Energy specifically recommends it for exactly this scenario.

The DOE's Energy Saver program states that for mixed climates, building owners should "select windows with both low U-factors and low SHGCs to maximize energy savings in temperate climates with both cold and hot seasons." Solar Gard Ecolux 70 is the only film in The Window Place USA's catalog engineered specifically to this DOE specification — delivering low-emissivity performance that reduces both summer heat gain and winter heat loss.

What Is Low-E Window Film and Why Does the DOE Recommend It?

Low-emissivity (Low-E) coatings work by reflecting infrared (heat) energy. In summer, a Low-E film reflects solar infrared radiation back outward, reducing heat gain. In winter, the same film reflects interior infrared radiation back inward, reducing heat loss through the glass. This bidirectional performance is what makes Low-E technology uniquely suited to mixed climates.

"Choose a low U-factor for better thermal resistance in colder climates; the U-factor is the rate at which a window conducts non-solar heat flow. Look for a low solar heat gain coefficient (SHGC). SHGC is a measure of solar radiation admitted through a window." — U.S. Department of Energy, Energy Saver

The NREL's 2024 window film study confirmed that films with balanced thermal performance — moderate SHGC reduction combined with low-emissivity properties — deliver the best year-round energy savings in mixed climate zones (Climate Zones 4 and 5 in the DOE's climate classification system).

Ecolux 70 Low-E: Technical Specifications

The 30% Federal Tax Credit for Low-E Window Film

The IRS's Energy Efficient Home Improvement Credit (Section 25C) provides a 30% tax credit for qualifying energy efficiency improvements to residential properties, up to an annual maximum of $1,200. Low-E window film that meets the DOE's energy performance standards qualifies for this credit.

Eligibility note: The 30% residential tax credit applies to the primary residence of the taxpayer. Consult your tax advisor for eligibility determination.

Why Government and Commercial Buyers Choose Ecolux 70

For federal agencies, state governments, and commercial building owners, Ecolux 70 delivers operational cost reduction at scale. A federal office building with 50,000 square feet of glass in a mixed climate may spend $200,000 to $400,000 annually on HVAC energy. A Low-E window film retrofit that reduces HVAC load by 15 to 25 percent delivers $30,000 to $100,000 in annual savings — with an installation cost that is typically recovered in 2 to 4 years.

The Window Place USA accepts P-Card purchases and agency quotes for Ecolux 70 and all Solar Gard products. We are SAM.gov registered and ship to all 50 states via Standard Ground/Freight Shipping.

Shop Ecolux 70 Low-E Window Film →

Contact Us for a Quote →

References

1. U.S. Department of Energy, Energy Saver. "Update or Replace Windows." energy.gov
2. Kim, J., CaraDonna, C., & Parker, A. (2024). "End-Use Savings Shapes Measure Documentation: Window Film." NREL/TP-5500-86554. nrel.gov
3. IRS. "Energy Efficient Home Improvement Credit." irs.gov