How to Find a Window Manufacturer in the US

To find a window manufacturer in the US, start by pinning down the product you need: window type, frame material, climate zone and project type. Then build a shortlist from a directory of manufacturers and brands. Check each candidate's certifications at the source: NFRC-certified energy ratings, ENERGY STAR certification for your climate zone, and AAMA Gold Label (or similar) certification for structural and air and water performance. GlassBase lets you browse window companies by city, brand and project type, and component brands by product type.

Step 1: Define what you need

• Product: windows, doors, skylights or components such as profile systems, glass or spacers.
• Project: replacement, new construction, repair or historic work.
• Climate: look up your ENERGY STAR climate zone with the ENERGY STAR climate zone finder. The zone sets the U-factor and SHGC limits a certified window must meet. See Window energy ratings in the US for the current table.
• Building type: ENERGY STAR's window criteria apply to residential buildings of three stories or less. Products for non-residential buildings are outside these criteria.

Step 2: Build a shortlist in the GlassBase directory

• Window companies lists installers, dealers and manufacturers. Filter by city, with a search radius, for example Chicago, IL or Houston, TX.
• By brand: brand pages follow the pattern /windows/tm-{brand} and show window companies filtered by that brand. Choose a brand in the Brand filter on the Windows page.
• By project type: replacement, new construction, repair and historic.
• Brands lists makers of components used in window production, by type: profile systems, glass, spacers and more.
• Suppliers lists companies that supply profiles, glass, hardware and materials to the window trade. Door companies are in Doors.

A listing in a directory is not a certification. Check every candidate in Step 3.

Step 3: Check certifications at the source

NFRC certified energy ratings

The National Fenestration Rating Council (NFRC) is an independent, nonprofit certification body for the energy performance of windows, doors and skylights. Certified products carry an NFRC label with U-factor, SHGC and visible transmittance, and optionally air leakage and condensation resistance. Search the product line in the NFRC Certified Products Directory. Ratings belong to specific products, so ask which product lines and glazing options are certified.

ENERGY STAR certification

ENERGY STAR is a program of the US Environmental Protection Agency (EPA). Under Version 7.0, a window must have NFRC-certified U-factor and SHGC ratings that meet the limits for a climate zone, and must be certified by a certification body recognized by EPA. Certified windows must display the ENERGY STAR product certification label. A manufacturer may call itself an ENERGY STAR partner only if at least one of its products is certified and offered for sale. To check:

• Search the ENERGY STAR Product Finder for windows, doors and skylights by brand and climate zone.
• See the ENERGY STAR list of partner manufacturers and retailers.

One certified product is enough for partner status, so look up the exact product line as well as the company.

AAMA Gold Label (FGIA)

The AAMA Gold Label Certification Program is run by the Fenestration and Glazing Industry Alliance (FGIA). A sample of the product is tested to the North American Fenestration Standard (AAMA/WDMA/CSA 101/I.S.2/A440), which covers air leakage, water penetration, structural resistance and durability. Two unannounced plant inspections each year check that production matches the tested product. Certification is valid for five years from the test date and can be extended. Check products in the FGIA Certified Products Directory.

ENERGY STAR Version 7.0 also accepts the AAMA Gold Label, the WDMA Hallmark label and certain other NAFS certification labels as proof that a window meets its air leakage limit of 0.3 cfm/ft².

Step 4: Ask for documents

• The NFRC ratings for the exact product line, glazing and spacer you are quoting.
• The ENERGY STAR climate zones the product is certified for.
• Any NAFS certification label and the product's tested performance.
• Installation instructions. ENERGY STAR requires certified products to have them available online or in the package.

Step 5: Compare options with the calculator

Use the GlassBase window energy calculator to compare frame and glazing combinations at your ZIP code before you request quotes. It shows calculated U-factor and SHGC and the yearly heating and cooling savings against a reference window. Its values are estimates, not NFRC ratings, so base the final decision on the certified ratings from Step 3. Terms used on this page are explained in the glossary.

Sources

• NFRC, nfrc.org, Residential product certification and Certified Products Directory
• NFRC consumer guide, Window ratings
• US EPA, ENERGY STAR, Residential Windows, Doors, and Skylights Program Requirements: Partner Commitments and Eligibility Criteria, Version 7.0
• US EPA, ENERGY STAR, Product Finder, partner list and climate zone finder
• FGIA, AAMA Gold Label Certification Program and Certified Products Directory