Custom Windows, Doors, Siding, Roofing & Gutters in Sag Harbor, NY
Exterior Home Services Tailored for Sag Harbor’s Historic Charm
From historic homes along Madison Street to modern estates in North Haven, Sag Harbor homeowners trust Thermo-Seal for expert exterior upgrades that honor the village’s character and withstand its coastal climate. For over 35 years, we’ve installed premium windows, doors, siding, roofing, and gutters built to preserve architectural heritage while adding energy efficiency and value. Whether you’re restoring a whaling-era house or updating a modern retreat, Thermo-Seal delivers white-glove service and flawless results across Sag Harbor and the East End.
Unlike other exterior remodelers, we never use subcontractors—our full-time team ensures consistent quality and superior results. With elite-level certifications from leading manufacturers, such as Andersen Premier Certified Contractor, GAF Master Elite Contractor, and James Hardie ALLIANCE member designations, we bring the highest standards to every project.
WINDOWS
DOORS
SIDING
Roofing
Gutters
Window Replacement in Sag Harbor
We install custom windows that blend seamlessly with historic colonial and Federal-style architecture, including double-hung and picture windows that maintain period accuracy while improving comfort. Energy-efficient glass and coastal-grade materials are ideal for homes near the harbor.
Upgrade your home with high-performance Andersen windows, including composite Fibrex®, wood, fiberglass, and vinyl options. We also offer premium selections from Pella and Harvey, all backed by a limited lifetime warranty. Our expertly installed energy-efficient windows enhance curb appeal, improve insulation, and provide long-lasting durability with superior craftsmanship.
Exterior Doors in Sag Harbor
Our doors enhance curb appeal and security for homes ranging from traditional village properties to new constructions in Noyac. Choose from fiberglass, steel, or wood-look entry doors, French or sliding patio doors, and durable storm doors custom-fitted to your home’s style.
We install Therma-Tru, Andersen, Pella, and Harvey doors, offering top-quality entry, sliding glass, French, and storm doors. Choose from wood, vinyl, fiberglass, or steel options, all of which deliver enhanced security, insulation, and style. Our expertly installed doors improve energy efficiency while elevating the beauty and functionality of your home’s entrance and living spaces.
Siding Installation in Sag Harbor
Thermo-Seal siding enhances homes with cedar-style shake, fiber cement, or insulated vinyl that withstands salt air and heavy storms. Our siding matches the aesthetic of Sag Harbor’s historic district, while improving durability and insulation for today’s standards.
Enhance your home’s exterior with James Hardie fiber cement siding, known for its durability, weather resistance, and stunning appearance. We also proudly offer vinyl siding from CertainTeed and Westlake Royal Building Products, as well as cedar shake siding which will add a touch of natural warmth to your home. Available in multiple styles, our siding options provide superior protection and timeless beauty with minimal maintenance.
Roofing in Sag Harbor
Whether your roof features ornate detailing or a modern flat design, we offer asphalt shingles, standing seam metal, and clay tile roofing solutions that balance longevity and authenticity. Perfect for older homes on Glover Street or new builds near Long Beach.
Protect your home with premium roofing solutions, including GAF asphalt shingles, tile, metal, and copper roofing. As a GAF Master Elite Contractor, we ensure expert installation and long-term durability. Our high-quality materials and professional craftsmanship offer superior weather resistance, energy efficiency, and a long-lasting, beautiful roof built to withstand the elements.
Gutter Systems in Sag Harbor
We install seamless gutters with custom sizing, perfect for preserving rooflines on historic homes or protecting expansive new constructions. Add leaf protection to reduce maintenance and extend lifespan.
Protect your home’s foundation with a seamless gutter system and gutter protection solution. Our high-performance gutters efficiently channel water away from your home, preventing costly water damage and erosion. Designed for durability and minimal maintenance, our systems keep your home safe while minimizing the need for gutter cleaning.
What Our Clients Are Saying
We strive to make the entire home remodeling experience positive for our customers—from your first phone call, until the final handshake.
“I had a very good experience with Thermo-Seal. Chose them after interviewing many others because they’re local, communicated efficiently, and offered good midrange pricing and lifetime warranty. The crew did a fantastic job with the installation. They came early and finished 5 windows in 5 hours, and then they cleaned up. Highly recommended!”
Patrick B.
“We just completed a window and siding job for our home with Thermo-Seal. We are very impressed and satisfied with the quality of their products as well as the installation. I would recommend this company & I would use them again in the future if needed.”
Mindy L.
“The crew was a pleasure to work with, and we love our new windows. The installation was efficient, and the team was very professional. I’ve seen a difference in my heating bill since the install, which was our primary goal so we are very happy so far! I will work with Thermo-Seal again for a front door replacement when the time comes.”
Bonnie K.
“We hired Thermo-Seal for new windows and siding and I could not be happier! Their team is on time, professional, and meticulous about their work. You can tell they take pride in their output and ensure things are done correctly the first time around. The project completed ahead of schedule and we were kept in the loop the entire time. Very happy with their work and highly recommended!”
Sarah C.
“We were referred to Thermo-Seal by a neighbor who was very pleased with the results. We replaced seven windows and a sliding patio door are thrilled with the results and how much they enhance the appearance of our home. Without hesitation, we recommend Thermo-Seal for your home improvement projects.”
Frank D.
“Cannot believe how stress-free an experience it was dealing with Aaron and his team. Aaron was very patient with our multiple questions and never any sales pressure. The installation was clean, quiet and the installation team friendly and helpful. The windows were installed a few weeks before they were promised and there were no surprises. We will be strongly recommending Thermo-Seal to friends looking for replacement windows.”
David B.
Why Sag Harbor Homeowners Trust Thermo-Seal
For over 40 years, homeowners have trusted Thermo-Seal for its superior exterior remodeling services. We deliver expert craftsmanship, high-quality materials, and an unwavering commitment to customer satisfaction. With a proven reputation, professional in-house installers, and industry-leading warranties, we ensure every project is completed with precision, care, and lasting value.
Free, No-Hassle Estimates
We believe in transparency and convenience. Our free, no-obligation estimates give you a clear understanding of your project’s scope and cost—no pressure, no hidden fees, just honest advice.
In-House Installers
Unlike many contractors, we never use subcontractors. Our full-time installers ensure consistent craftsmanship, quality, and accountability, delivering superior results ever time.
Decades of Experience
Since 1985, we’ve been transforming homes across the Tri-State area. With more than 40 years of expertise, we provide top-quality remodeling solutions backed by a trusted reputation.
100% Satisfaction Guaranteed
Your happiness is our priority. We back every project with a 100% Customer Satisfaction Guarantee, ensuring you receive high-quality service and results that exceed expectations.
Certified. Trusted. Proven.
When you work with Thermo-Seal, you can expert craftsmanship backed by trusted credentials. We’ve partner with the industry’s leading manufacturers, earning their top certifications to bring you the best products on the market. As a fully licensed and insured company, we ensure your investment is protected at every step.
