Landmark Windows Meet High Performance

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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Door Anatomy | Guide to Parts, Terms and Functions

The anatomy of a door, exterior.

When it comes to historic preservation, the elegance of a door lies not only in its design but also in its anatomy. From grand entryways in landmark buildings to charming brownstone doors in New York City, understanding the parts of a door can help you make more informed decisions. Here’s a breakdown of the essential components that make up a traditional door system.

The Basics

Doorway
The doorway is the opening itself, the passage you walk through to enter a home or room.

Door Frame
Supporting the door panel, the frame includes three key parts: the head (top), jambs (sides), and sill (bottom). Frames are typically constructed from wood, steel, or aluminum, depending on the style and era of the building.

Door Panel
This is the main part of the door that swings open and shut. It can feature solid wood, glass panes, or decorative detailing, depending on the architectural style.

Structural & Functional Elements

Head (or Door Head)
The horizontal top part of the frame.

Jamb
The vertical sides of the frame where the hinges, latch, and strike plate are mounted.

Sill
Located at the bottom of the frame, it sits flush with the floor.

Threshold
Often a sloped piece installed over the sill, the threshold helps keep water and drafts from entering the home.

Weatherstripping & Door Sweep
These components are critical for sealing gaps and improving energy efficiency. Weatherstripping lines the perimeter of the door panel, while the door sweep covers the gap at the bottom.

In-Swing vs. Out-Swing
Depending on your building’s layout or historical context, doors may swing inward or outward. This is typically determined by the positioning of hinges and how the space is used.

Design & Decorative Components

Rails & Stiles
Rails are horizontal segments on the door panel, while stiles run vertically. These structural elements often define the style of the door and house the hardware.

Mullions
A mullion (or “mull”) is the vertical or horizontal element that separates and joins multiple door panels or connects sidelights or transoms to the main door.

Casing & Brickmould
These trim elements add architectural interest and help hide the transition between the door frame and wall—casing on the interior and brickmould on the exterior.

Grilles
Grilles are decorative dividers that mimic the appearance of individual glass panes. They can be surface-applied or installed between panes of insulated glass.

Dentil Shelf
A signature feature of craftsman-style doors, this is a small ledge typically placed below a window pane for decorative effect.

Glazing (Glass)
Historic doors often feature beautiful glasswork. Today, glazing is usually insulated and may include decorative patterns, beveled edges, or leaded details.

Sidelights & Transoms
Sidelights are narrow, vertical windows flanking the door, while transoms sit above it. Both let in natural light and add visual grandeur to an entryway.

Hardware & Security Features

Hinges
These allow the door panel to pivot open and closed. Styles range from exposed barrel hinges to concealed or pivot hinges in modern or minimalist applications.

Knob or Handle
The main mechanism for opening a door. Knobs are round, while handles can vary in design—lever or pull-style depending on preference and accessibility.

Lockset
This includes all elements related to door locking: the handle, latch, strike plate, and interior locking mechanisms.

Deadbolt
An added layer of security, the deadbolt slides a solid metal bolt into the frame and is usually operated by a key or thumb turn.

Latch
The latch retracts when the handle is turned, allowing the door to open. It extends automatically when the door is closed.

Mortise Plate & Strike Plate
These metal reinforcements are located in the jamb and receive the latch or deadbolt. They enhance security and durability by preventing forced entry.

Astragal
If you have double doors, the astragal is the vertical strip that seals the gap between both panels and helps keep the doors secure and aligned.

Planning a full exterior restoration? Don’t miss these window guides.

Understanding window parts is key to choosing, restoring, and preserving historic windows. Learn more in our Window Anatomy Guide, and explore glass types and glazing details in Glass: What a Pane.

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A Lot on the Line | Installing Fire-Rated Lot Line Windows in TriBeCa

Installing 350-pound, 10-foot-tall steel fire-rated ceramic glazed lot line windows is no easy feat—especially in a historic TriBeCa building with just five feet of clearance between neighboring structures. When working several stories up, over skylights and alleyways, precision is key. These projects demand careful planning, expertise, and patience to ensure both compliance and craftsmanship.

We recently undertook the replacement of 130-year-old double-hung wood weight and chain windows on White Street—one of our favorite streets in Lower Manhattan, where we’ve worked on numerous projects over the years. Given the building’s age and NYC’s strict building codes, these new single-hung steel windows from Optimum Window were essential. The upgrade ensures compliance with both fire safety regulations and NYC Landmarks Preservation Commission requirements while preserving the historic character of the building.

Why Lot Line Windows Matter

Lot line windows are installed on walls that sit directly along a property line, meaning they must meet fire-rated standards to protect against potential fire spread between closely spaced buildings. These new steel-framed windows provide:

• Improved Fire Safety: The ceramic glazing and thermally broken steel frames enhance the fire resistance required for lot line windows.

• Sound Attenuation: The DB/OITC-rated glazing significantly reduces noise pollution—a major benefit in New York City.

• Energy Efficiency: The insulated steel frames and thick glazing offer better thermal performance, keeping interiors more comfortable year-round.

Preserving History While Enhancing Performance

One of the most rewarding aspects of this project was the careful attention to historical detailing. Custom interior casings were fabricated to match the original woodwork, ensuring that the new windows blend seamlessly into the building’s architectural style.

As this transformation nears completion, it’s clear that upgrading historic windows is more than just an aesthetic choice—it’s a structural and safety necessity. With proper planning, expert craftsmanship, and respect for historical integrity, even the most challenging projects can be executed flawlessly.

Winter-Proofing Historic Brownstones | Energy-Efficient Window Solutions

New York City’s historic brownstones are treasured for their architectural beauty and timeless charm. However, as winter sets in, these classic buildings often face challenges when it comes to energy efficiency. Aging windows, drafty frames, and single-pane glass can make it difficult to keep homes warm and energy bills manageable. The good news is that preserving the character of your historic brownstone doesn’t mean sacrificing modern comfort.

Here are energy-efficient solutions that will keep your brownstone cozy while maintaining its historic integrity:

Window Restoration for Better Insulation

Restoring your existing historical windows can greatly improve their energy performance. Professional restoration services can repair drafts, improve seals, and add insulation while preserving the original design. This approach ensures compliance with NYC’s landmark preservation requirements and maintains the unique character of your brownstone.

Adding Storm Windows

Storm windows are a simple yet effective way to enhance energy efficiency without altering your original windows. Custom storm windows can be installed to match the aesthetic of your brownstone while adding an extra layer of insulation against the cold.

Upgrading to Energy-Efficient Glazing

If your windows are beyond repair, consider upgrading to energy-efficient glazing. Double or triple-pane glass offers superior insulation and can be customized to replicate the look of historical windows, ensuring your brownstone retains its charm while meeting modern efficiency standards.

Sealing Gaps and Drafts

Even the smallest gaps around window frames can lead to significant heat loss. Weatherstripping and caulking are cost-effective solutions to seal these gaps, preventing drafts and keeping your home warm all winter long.

Insulating Window Treatments

Thermal curtains, shades, and blinds not only add a stylish touch to your brownstone but also provide an additional layer of insulation. They can help retain heat during chilly NYC winters while complementing your historic interior.

Why Choose Professional Window Services for Your Brownstone?

NYC brownstones are often protected under landmark status, meaning any modifications must comply with strict guidelines. Working with Historical Windows of New York ensures that your energy-efficient upgrades meet these regulations while maintaining the architectural integrity of your home. Our team specializes in restoring and upgrading historic windows for NYC brownstones, combining expert craftsmanship with modern technology to achieve the best results.

Schedule Your Consultation Today

Don’t let winter drafts take away from the comfort of your historic brownstone. Contact us to learn more about energy-efficient solutions for your windows. Whether you need restoration, storm window installation, or an upgrade to energy-efficient glazing, our team is here to help.

Ready to get started? Contact us today for a consultation!

NYC’s Preservation Laws | Restoring Historical Windows

New York City is home to countless iconic buildings, many of which are designated as landmarks due to their historical significance and architectural beauty. A critical part of maintaining these buildings is the preservation of their original windows. If you own or manage a landmarked property, understanding NYC’s preservation laws is essential when it comes to restoring or replacing historical windows. We specialize in custom historic windows and ensure compliance with all regulations, making the restoration process stress-free and seamless.

Why Preservation Laws Matter for Historical Windows

The Landmarks Preservation Commission (LPC) is responsible for overseeing modifications to landmarked properties in NYC, including window restoration and replacement. These guidelines are in place to protect the architectural integrity of buildings and ensure that any changes are consistent with their historical character.

If your building is under landmark status, making unauthorized changes to your windows, such as installing modern replacements that don't match the original style, can lead to penalties and costly retrofits. That's why it’s essential to work with an experienced window company near you that is familiar with LPC’s guidelines for historical windows.

Key Guidelines for Restoring Landmarked Windows in NYC

When working on landmarked windows in New York, there are several key guidelines you must follow:

1. Matching Original Materials and Design: Any restoration or replacement of historic windows must match the original design, material, and details. Whether your building features double-hung, casement, or arched windows, they need to be replicated as accurately as possible. Our window company in NYC offers custom historic windows that meet these exacting standards.

2. Energy-Efficient Upgrades: While LPC encourages maintaining historical accuracy, they also recognize the importance of energy efficiency. You can often install energy-efficient glass and materials as long as they don’t alter the window’s appearance.

3. Consultation and Approval: Before starting any restoration or replacement project, you must get approval from the LPC. They will review your plans to ensure the new or restored windows meet their guidelines. Our team handles this process, ensuring that every project adheres to local preservation laws.

4. Window Repair vs. Replacement: The LPC prefers that original windows be repaired rather than replaced. If your windows are beyond repair, they may approve a full replacement, but only if the new windows are an exact match to the originals in terms of materials, details, and craftsmanship.

Our Expertise in Custom Historic Windows and Restoration

As a trusted window company in New York City, we have extensive experience navigating these preservation laws and successfully restoring landmarked windows across the city. Whether you're restoring original windows or replacing them with custom historic windows, our team has the expertise to ensure your project complies with LPC requirements.

We use high-quality materials to restore windows to their former glory while incorporating modern features such as energy-efficient glazing. Our team can work with you throughout the consultation and approval process to ensure your project meets all necessary guidelines, saving you time and potential penalties.

When to Replace or Restore Your Historic Windows

Many property owners struggle with the decision to replace or restore historic windows. Restoration is often the preferred choice, as it maintains the building's authenticity and avoids any compliance issues. However, if the windows are too damaged for restoration, our window replacement services in New York City can create custom historic windows that match the original style exactly.

Whether you need repairs, restoration, or full replacement, we have the tools, skills, and experience to deliver top-quality results while adhering to all LPC regulations.

Contact Us for Expert Window Restoration in NYC

Restoring or replacing landmarked windows can be a complex process, but with our help, you can ensure compliance with NYC’s preservation laws while enhancing your property’s energy efficiency and value.

If you're looking for a window company near you that understands the intricacies of working with historical windows, contact us today for a free consultation. Let us help preserve your building’s heritage while meeting the demands of modern living.

Top 5 Architectural Window Styles in Historic New York Homes

New York City is known for its rich architectural history, with buildings that showcase a variety of window styles from different eras. These windows not only contribute to the aesthetic beauty of the buildings but also reflect the cultural and historical significance of the time in which they were built. Understanding the different window styles can help you preserve your building’s original charm while ensuring compliance with preservation laws.

As a leading window company in New York City, we specialize in restoring and replacing landmarked windows and custom historic windows. Below, we explore the top five architectural window styles found in historic New York homes and buildings, offering insights into how they can be restored or replicated.

Double-Hung Windows

Double-Hung Windows

One of the most common window styles found in historic New York homes is the double-hung window. These windows feature two vertically sliding sashes, allowing both the top and bottom panes to be opened. Double-hung windows were popular in many architectural periods, from Colonial and Federal styles to Victorian townhouses and brownstones.

If your building has original double-hung windows, preserving their function and appearance is essential. Our window company near you can restore or create custom historic windows that maintain the traditional look while improving energy efficiency with modern materials.

Casement Windows

Casement Windows

Casement windows, which open outward like a door, are another common feature of historic homes, especially in early 20th-century buildings. These windows offer excellent ventilation and were often used in high-end townhouses and early apartment buildings.

Restoring historical windows like casement windows requires precision and expertise to retain their original design. Our window replacement services in New York City ensure that any casement window replacements match the building's architectural period.

Palladian Windows

Palladian windows, known for their grandeur, feature a large central window flanked by two smaller, arched windows. This design originated in classical European architecture and became popular in New York during the 19th century, especially in grand estates and public buildings.

Bay Windows

These elegant windows are often focal points of historic buildings, making restoration critical. Our window company in NYC specializes in landmarked window restoration, ensuring that your Palladian windows retain their beauty and compliance with NYC preservation laws.

Arched Windows

Arched windows are a hallmark of Beaux-Arts and Romanesque Revival architecture, two styles that heavily influenced New York's historic buildings. These windows feature rounded tops and intricate detailing, often found in churches, libraries, and ornate residential buildings.

Restoring arched custom historic windows requires careful attention to detail to preserve their intricate design. Our team is skilled in restoring these complex windows, maintaining their structural integrity while upgrading them to meet modern energy standards.

Bay Windows

Bay windows, often found in late 19th and early 20th-century townhouses, extend outward from the building’s façade, creating more interior space and allowing for additional light. These windows are commonly seen in Victorian and Queen Anne-style homes throughout New York City.

Replacing or restoring bay windows can be tricky due to their unique shape and size, but our window company near you specializes in creating custom historic windows that perfectly replicate the original style. We also offer solutions for improving insulation and weatherproofing, keeping the look authentic while enhancing performance.

Why Custom Historic Windows Matter for Landmark Preservation

Preserving the original architectural window styles in landmarked and historic properties is crucial for maintaining the building’s authenticity and complying with New York City’s preservation laws. The Landmarks Preservation Commission (LPC) requires that any restoration or replacement of landmarked windows matches the original design and materials, ensuring the building retains its historical significance.

At our window company in NYC, we have extensive experience working with historical homes and buildings, offering custom solutions for window restoration and replacement. Whether you're dealing with aging double-hung windows or intricate Palladian windows, we ensure that every project meets the LPC’s guidelines and enhances the overall value of your property.

Contact Us for Historic Window Restoration in New York City

If you’re looking to restore or replace the windows in your historic New York home, our team is here to help. As a trusted window company near you, we specialize in landmarked window restoration and custom historic windows that retain the beauty and integrity of your building’s original design.

Contact us today to schedule a consultation and learn more about our window replacement services in New York City. Let us help preserve your property’s unique architectural style while improving its functionality and energy efficiency.

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