Common Questions for High Performance Windows
When most people hear Landmark Windows, they think historic, and historic doesn’t always sound like high performance. We often get questions about whether landmark-approved windows can truly meet today’s standards. To clear up some of the most common misconceptions, our team put together answers to the questions we hear most often.
Are Landmark Windows Still ENERGY STAR® Certified?
Yes. Many people are surprised to learn that Landmark Windows can be built to meet ENERGY STAR® certification. By using modern glazing, thermal breaks, and low-E coatings, they offer insulation and efficiency comparable to today’s top-performing windows, while still keeping the historic look that’s required for landmarked buildings.
How Do Landmark Windows Compare to Newer High-Performance Brands?
It’s a fair question — newer brands market themselves heavily on performance. What we’ve seen in our projects is that Landmark Windows hold their own. They meet the same performance ratings for insulation and sound as modern competitors, but with the added benefit of being custom-built to match historic detailing. That’s something you won’t find in a mass-produced window.
At 214 West 16th Street, we installed period-correct Norwood NorClad double-hung windows approved by the Landmarks Commission. Norwood’s data for this line shows U-factors in the 0.27–0.33 range with standard double-pane builds, and even lower with higher-performance options. In practice, these windows delivered the same efficiency as modern high-end brands, with the added benefit of historic accuracy.
Do Landmark Windows Still Meet 2025 Energy Efficiency Standards?
Yes. As codes tighten, Landmark Windows can be specified with the upgrades needed, from insulated glass units to gas fills and thermally broken frames, to stay ahead of the requirements. We work with these options regularly to ensure our installations meet both NYC Landmarks Preservation Commission rules and current energy codes.
On the White Street lot-line project in TriBeCa, we installed 350 lb., 10 ft. tall Optimum fire-rated steel lot-line windows. Along with fire safety, these units were built with thermally broken frames and high-performance glazing that meet today’s code and are equipped to satisfy future standards.
Are Landmark Windows Worth It Compared to Newer Competitors?
From our perspective, absolutely. Many off-the-shelf windows may seem like a bargain, but they often won’t pass Landmarks review, which can cost you time and money. Landmark Windows give you the best of both worlds: code compliance, long-term energy savings, and historic accuracy. That combination is what makes them a smart investment in the long run.
At 17 St. Luke’s Place, we installed Parrett double-hung and French casement windows with custom brick moulds and interior casing. Parrett’s test data shows their windows achieving STC ratings into the high 30s and OITC ratings in the 30s, depending on glazing. That means you’re not only getting historically accurate units but also proven acoustic and energy performance.
What’s the Current Warranty and Performance Rating of Landmark Windows?
Manufacturers we work with provide strong warranties that cover frames, glazing, and finishes. Performance ratings meet or exceed industry standards, offering peace of mind that your investment delivers both beauty and efficiency for decades.
17 St. Luke’s Place | Parrett Windows Custom Double Hung & French Casement Windows (Landmark Approved)
White Street, TriBeCa | Optimum Window Single Hung Steel Fire-Rated Lot Line Windows (DB/OITC Rated, Landmark + Code Compliant)
NYC | Double Pane Weight & Chain Windows (Landmark Approved, Energy Efficient, Code Compliant)
East Village | Parrett Windows Triple Hung Weight & Chain Windows (Landmark Reproduction)
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