Window Frames

Window Frames Product Guidance

Use the red-to-green product guidance below to select safer product types by avoiding those in red and preferring yellow and green, which are safer for occupants, fenceline communities, and workers.

When choosing window frames:

This guidance covers materials used for the window frame only and does not assess materials common across window types including glass panes, films, sealant, seals, spacers, gas fill, and hardware. These materials may include additional hazards not considered here. While this guidance is specific to window frames, it may also be applicable to storefronts or curtain walls.

Product rankings for window frame materials were largely driven by hazards present in the manufacturing phase, which affect workers and communities near manufacturing facilities. No window frame options considered are fully free of hazardous chemical impacts. For instance, the International Agency for Research on Cancer (IARC) classifies occupational exposures during aluminum production as carcinogenic to humans.[1] IARC also classifies wood dust as carcinogenic to humans and formaldehyde as probably carcinogenic to humans,[2] both of which are present in wood window manufacturing. Vinyl and PVC-wood composite frames rely on polyvinyl chloride (also called vinyl or PVC), a plastic polymer that requires hazardous inputs such as carcinogenic ethylene dichloride and vinyl chloride monomer.[3] These toxic inputs put communities at risk, as evidenced by the 2023 East Palestine, OH train derailment which released vinyl chloride into the surrounding community.[4] Fiberglass frames also contain a significant portion of plastic, which relies on the carcinogen styrene.[5]

While all window frame options include chemical hazards, some product types are worse than others when considering their impacts across the life cycle. Vinyl, composite, and fiberglass frames contain a significant proportion of plastic, made from petrochemicals, which are derived from oil and natural gas. Living in close proximity to oil and gas wells has been associated with numerous health impacts, including adverse pregnancy outcomes, cancer, exacerbation of asthma, and mental health issues.[6] A recent body of research also demonstrates that oil and gas wells are disproportionately located near historically redlined communities with a high proportion of people of color, contributing to environmental injustices.[7] 

Plastic products also present hazards at end of life. Despite claims of recyclability, in practice plastic windows, as with many plastic products, are not recycled at scale.[8] They are largely landfilled or incinerated, where they present additional hazards including microplastic generation[9] and toxic incineration byproducts such as dioxins, a class of persistent, bioaccumulative, and toxic chemicals.[4,10] Aluminum and wood building materials are also largely landfilled, though are reused or recycled at higher rates than their plastic counterparts.[11]

Many window frame materials require coatings and vinyl and fiberglass frames may be optionally sold with insulation. Both coatings and insulating materials add chemical hazards. See below for information on insulation and coatings by frame type.

Below is more detailed guidance to use when choosing window frames:

  • Prefer window frame materials that are based on wood or metals. These materials have fewer hazards throughout the lifecycle of the product, including less hazardous manufacturing processes.
  • Reduce or avoid plastic materials, particularly vinyl, PVC-clad, and PVC composite. Plastic materials rely on fossil fuel inputs that negatively impact surrounding communities.[6] They also result in landfilling or incinerating at the end of their useful life which generates additional hazards.[4,9,10] PVC (also called vinyl and polyvinyl chloride) is one of most toxic plastics and a high priority to avoid.
  • Avoid foam insulation in frames. Common foam window insulation includes EPS, which uses a hazardous halogenated flame retardant and increases the overall product’s reliance on plastic materials.
  • Coatings add hazards; view frame-specific guidance below. Where possible, prefer anodized coatings for metal frames, waterborne coatings that are low-VOC and PFAS- and APE-free for wood frames, and integrally colored frames that don’t require additional coatings for fiberglass.

Aluminum window frames are made from extruded aluminum alloy, a relatively low-hazard material that is recycled; these products may contain a high amount of recycled aluminum. Because aluminum conducts heat readily, windows in certain applications may be thermally broken, meaning they employ a non-conducting plastic material between interior and exterior portions of the window frame to improve thermal properties. These thermal breaks most often consist of polyamide strips or poured-in-place polyurethane, representing a small percentage of the overall window frame by weight. Hazards will vary based on the type of plastic, but in general reducing plastic content is preferred as plastics are typically made from fossil fuel feedstocks that have significant lifecycle hazards.

Aluminum frames require treatment or coating, which will affect the chemical hazards and length of life of the frame. Anodization is a relatively low hazard aluminum finish option.

Within this type watch out for: Aluminum frames that have chromate pretreatment and PFAS-based coatings such as PVDF and FEVE, which are ranked red in this guidance.

Wood window frames are made of individual wood members that have been glued together. Adhesives may include polyvinyl acetate (PVA) used with isocyanates and formaldehyde-based adhesives,[12] both of which create health hazards. Wood windows are commonly treated with preservatives to deter mold, mildew and pests. There are numerous wood preservatives that are commonly used in exterior wood applications such as iodo-2-propynyl butyl carbamate, borate esters, triazole fungicides, and many others.[13] Hazards vary depending on the preservatives used.

Wood windows require coating on the interior and exterior to protect wood from degradation. Common coatings include oil-based stains and sealers, alkyd paints, latex paints, and urethanes. When selecting a coating consider length of coating life (re-coating can increase hazards over the lifetime), whether the coating is water- or solvent-borne, the type of binder used (e.g. acrylics, alkyds, urethanes, or epoxy), and whether the coating contains alkylphenol ethoxylates (APEs) and/or PFAS, which are highly hazards. Habitable’s InformedTM Interior Paint Product Guidance can assist in selecting healthier paints.

Within this type prefer: Wood windows that have been coated with low-VOC waterborne coatings formulated without APEs and PFAS.

Aluminum-clad wood window frames have a wood frame interior and an aluminum frame exterior. Frame components are comprised of similar materials as the aluminum and wood window frames and held together using mechanical mechanisms such as snap-fit designs or clips,[14] though adhesives may also be used.[15] Internal components may be plastic, including components made of PVC.[12] Coatings for the exterior are those offered for aluminum and coatings for the interior are those typically used on interior wood. See our Interior Paint Product Guidance for help in selecting healthier interior paints.

Within this type prefer: Low-VOC waterborne interior coatings formulated without APEs and PFAS.

Within this type watch out for: Exterior coatings that rely on PFAS-based paints, like PVDF.

The main component of fiberglass window frames is a mix of glass fibers and crosslinked polyester polymer, which acts as a binder. Lifecycle hazards associated with this material are primarily related to the plastic polymer binder. Styrene, a carcinogen, is commonly used for crosslinking. Plastics are derived from fossil fuels, the extraction and processing of which releases hazardous pollution that can have significant impacts on the health of people in surrounding communities. Polluting facilities are disproportionately located in BIPOC and low-wealth communities, contributing to environmental injustices. 

Within this type watch out for: Products with insulation, which are ranked orange in this guidance. Frames may be optionally insulated depending on the application. Products without insulation avoid the added chemical impacts associated with plastic foam insulation, which was found to most commonly be extruded polystyrene (EPS) and likely contains persistent, bioaccumulative, and toxic halogenated flame retardants.

The main component of fiberglass window frames is a mix of glass fibers and crosslinked polyester polymer, which acts as a binder. Lifecycle hazards associated with this material are primarily related to the plastic polymer binder. Styrene, a carcinogen, is commonly used for crosslinking. Plastics are derived from fossil fuels, the extraction and processing of which releases hazardous pollution that can have significant impacts on the health of people in surrounding communities. Polluting facilities are disproportionately sited in BIPOC and low-wealth communities, contributing to environmental injustices.[6]

Insulation is typically described as “foam” insulation. Extruded polystyrene (EPS), as well as other plastic foam insulation, likely contains persistent, bioaccumulative, and toxic halogenated flame retardants. 

Within this type prefer: Uninsulated frames that are ranked yellow in this guidance.

Aluminum window frames are made from extruded aluminum alloy, a relatively low-hazard, recycled material, so products may contain a high amount of recycled aluminum. Because aluminum conducts heat readily, windows in certain applications may be thermally broken, meaning they employ a non-conducting plastic material between interior and exterior portions of the window frame to improve thermal properties. Thermal breaks most often consist of polyamide strips or poured-in-place polyurethane,  representing a small percentage of the overall window frame by weight. Hazards vary based on the type of plastic, but in general reducing plastic content is preferred as plastics are typically made from fossil fuel feedstocks that have significant lifecycle hazards.

Aluminum frames do require treatment or coating, which affect their associated chemical hazards and length of life of the frame. Pretreatment for coating may include chromate treatments that may rely on hazardous chromium VI.[16] Chrome-free pretreatments are available.[17] Additionally, PVDF or FEVE coatings rely on per- or polyalkyl substances (PFAS), also known as forever chemicals. PFAS are a high priority to avoid as many are persistent, bioaccumulative, and toxic. Coatings that do not rely on PFAS include polyester powder coating and anodization (see above).

Within this type prefer: Anodized aluminum frames which are ranked green in this product guidance.

PVC-clad wood window frames, or vinyl-clad wood, are similar to aluminum-clad wood window frames except that they have a vinyl exterior and wood frame interior. PVC or “vinyl” is ranked red in this guidance because of the toxic processes required to make the plastic and the toxic pollution created when it is disposed of. For these reasons it ranks among the worst types of plastic[18] and should be avoided wherever possible.

PVC does not typically require coating as the PVC is integrally colored or has an acrylic co-extrusion. The wood interior is usually painted or stained. See our Interior Paint Product Guidance for help in selecting healthier interior paints.

Within this type prefer: Low-VOC waterborne interior coatings formulated without APEs and PFAS for the wood portion of the frame. However,these products are still some of the worst in class so aim to use different product types of products ranked yellow or green.

Wood-plastic composite window frames are made of wood fibers held together with a binder, typically PVC, though formaldehyde-based resins may also be used. Much of the wood fiber and some of the polymer binder may be from recycled sources, such as sawdust from the manufacture of wood windows and pre-consumer PVC from window manufacturing. Recycled PVC is a small percentage of the overall product so these windows still include a significant portion of virgin PVC. PVC has significant lifecycle concerns and should be avoided where possible (see Vinyl Window Frame).

Vinyl window frames are made of polyvinyl chloride (PVC), also called “vinyl”. The material may also be referred to as uPVC or unplasticized PVC. PVC has many lifecycle hazards, placing it among the worst plastics from a material health perspective.[18] Rigid (unplasticized) PVC used in window frames commonly contains organotin stabilizers, which are suspected developmental toxicants and may also cause damage to organs through prolonged or repeated exposure.[19] The production of PVC requires and generates hazardous chemicals including carcinogenic ethylene dichloride, vinyl chloride monomer, and dioxins, which are persistent, bioaccumulative, and toxic.[4,10] It is not currently common practice to recycle PVC at the scale it is used,[8] so these products are typically landfilled or incinerated, which produces additional chemical hazards.[4,10]

Vinyl windows without insulation avoid the added chemical impacts associated with plastic foam insulation but are still not a preferred option.

Vinyl window frames are made of polyvinyl chloride (PVC), also called “vinyl”. The material may also be referred to as uPVC or unplasticized PVC. PVC has many lifecycle hazards that rank it among the worst plastics from a material health perspective.[18] Rigid (unplasticized) PVC used in window frames commonly contains organotin stabilizers, which are suspected developmental toxicants and may also cause damage to organs through prolonged or repeated exposure.[19] The production of PVC requires and generates hazardous chemicals including carcinogenic ethylene dichloride, vinyl chloride monomer, and dioxins, which are persistent, bioaccumulative, and toxic.[4,10] It is not currently common practice to recycle PVC at the scale it is used,[8] so these products are typically landfilled or incinerated, which produces additional chemical hazards.[4,10]

Insulation is commonly offered as “foam” insulation. Extruded polystyrene (EPS) is commonly cited and likely contains persistent, bioaccumulative, and toxic halogenated flame retardants.

Within this type prefer: Uninsulated frames. However, these products are still some of the worst in class. Try to use a different type of product that is ranked yellow or green.

Supporting Information

Unless otherwise noted, product content and health hazard information is based on research done by Habitable for Common Product profiles, reports, and blogs. Links to the appropriate resources are provided.

Common Product Records Sourced

Endnotes

[1] Humans, I. W. G. on the E. of C. R. to. OCCUPATIONAL EXPOSURES DURING ALUMINIUM PRODUCTION. In Chemical Agents and Related Occupations; International Agency for Research on Cancer, 2012.

[2] IARC. Wood Dust and Formaldehyde.

[3] Healthy Building Network. Vinyl Chloride (VCM) 75-01-4. https://commons.healthymaterials.net/chemicals/2010833 (accessed 2018-07-10). Healthy Building Network. Ethylene Dichloride (EDC). https://commons.healthymaterials.net/chemicals/2004480 (accessed 2918-07-19).

[4] US EPA, R. 05. Background. https://www.epa.gov/east-palestine-oh-train-derailment/background (accessed 2024-07-18). Vinyl chloride and toxic waste. Toxic-Free Future. https://toxicfreefuture.org/research/pvc-poison-plastic/vinyl-chloride-and-toxic-waste/ (accessed 2024-06-27).

[5] Styrene. Pharos. https://pharos.habitablefuture.org/chemicals/2010381 (accessed 2024-08-13).

[6] Environmental Impacts of Natural Gas. Union of Concerned Scientists. https://www.ucsusa.org/resources/environmental-impacts-natural-gas (accessed 2021-05-21). Garcia-Gonzales, D. A.; Shonkoff, S. B. C.; Hays, J.; Jerrett, M. Hazardous Air Pollutants Associated with Upstream Oil and Natural Gas Development: A Critical Synthesis of Current Peer-Reviewed Literature. Annu. Rev. Public Health 2019, 40 (1), 283–304. https://doi.org/10.1146/annurev-publhealth-040218-043715. Deziel, N. C. Environmental Injustice and Cumulative Environmental Burdens in Neighborhoods Near Oil and Gas Development: Los Angeles County, California, and Beyond. Am. J. Public Health 2023, 113 (11), 1173–1175. https://doi.org/10.2105/AJPH.2023.307422. Deziel, N. C.; Clark, C. J.; Casey, J. A.; Bell, M. L.; Plata, D. L.; Saiers, J. E. Assessing Exposure to Unconventional Oil and Gas Development: Strengths, Challenges, and Implications for Epidemiologic Research. Curr. Environ. Health Rep. 2022, 9 (3), 436–450. https://doi.org/10.1007/s40572-022-00358-4.

[7] Gonzalez, D. J. X.; Nardone, A.; Nguyen, A. V.; Morello-Frosch, R.; Casey, J. A. Historic Redlining and the Siting of Oil and Gas Wells in the United States. J. Expo. Sci. Environ. Epidemiol. 2022, 1–8. https://doi.org/10.1038/s41370-022-00434-9. Berberian, A. G.; Rempel, J.; Depsky, N.; Bangia, K.; Wang, S.; Cushing, L. J. Race, Racism, and Drinking Water Contamination Risk From Oil and Gas Wells in Los Angeles County, 2020. Am. J. Public Health 2023, 113 (11), 1191–1200. https://doi.org/10.2105/AJPH.2023.307374. Chan, M.; Shamasunder, B.; Johnston, J. E. Social and Environmental Stressors of Urban Oil and Gas Facilities in Los Angeles County, California, 2020. Am. J. Public Health 2023, 113 (11), 1182–1190. https://doi.org/10.2105/AJPH.2023.307360. Donaghy, T.; Jiang, C. Fossil Fuel Racism: How Phasing Out Oil, Gas, and Coal Can Protect Communities; 2021. https://www.greenpeace.org/usa/reports/fossil-fuel-racism/ (accessed 2021-05-21).

[8] Geyer, R.; Jambeck, J. R.; Law, K. L. Production, Use, and Fate of All Plastics Ever Made. Sci. Adv. 2017, 3 (7). https://doi.org/DOI: 10.1126/sciadv.1700782. Mowrey, H. The Illusion of Plastics Recycling. Habitable. https://habitablefuture.org/content-hub/the-illusion-of-plastics-recycling-neither-just-nor-circular/ (accessed 2024-06-27).

[9] Wojnowska-Baryła, I.; Bernat, K.; Zaborowska, M. Plastic Waste Degradation in Landfill Conditions: The Problem with Microplastics, and Their Direct and Indirect Environmental Effects. Int. J. Environ. Res. Public. Health 2022, 19 (20), 13223. https://doi.org/10.3390/ijerph192013223.

[10] PVC at a Glance. Health Care Without Harm. https://noharm-uscanada.org/content/europe/pvc-glance (accessed 2024-06-27).

[11] US EPA, O. Wood: Material-Specific Data. https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/wood-material-specific-data (accessed 2024-04-26). AEA. Aluminum Windows EPD, 2020. https://api.environdec.com/api/v1/EPDLibrary/Files/11ed9f76-c75b-4817-bd94-483f825dd9fd/Data. Kawneer Windows EPD. https://www.kawneer.co.uk/kawneer_files/general/Sustainability/kawneer%20_window_epd_1.pdf (accessed 2024-08-13). Hueck Aluminum Frame Profiles for Windows and Doors EPD.https://hueck.com/dam/jcr:90f326d5-ab74-4b21-a5c9-bdeef86d8f77/2019-10-30_EPD_HUECK_Fenster-T%C3%BCren_Rahmenprofil_Eng.pdf (accessed 2024-08-13). Environmental Factoids | WasteWise | US EPA. https://archive.epa.gov/epawaste/conserve/smm/wastewise/web/html/factoid.html (accessed 2024-06-24).

[12] Andersen E Series HPD. https://hpdrepository.hpd-collaborative.org/repository/HPDs/246_Andersen_E_Series_Casement_Window.pdf (accessed 2024-06-25). Nicholson, J. W.; Hoffman, J. J. W. Treatment of Wood for the Production of Building Structures and Other Wood Products. US9339943B2, May 17, 2016. https://patents.google.com/patent/US9339943B2/en?q=(preservative)&assignee=jeld-wen (accessed 2024-06-25).

[13] Hoffman, M. C. Wood Preservative Composition. US20080221067A1, September 11, 2008. https://patents.google.com/patent/US20080221067A1/en?q=(windows)&assignee=sierra+pacific&oq=sierra+pacific+windows (accessed 2024-06-25). Bettin, T. J.; White, K. R. Wood Treatment Process. CA2168504A1, August 23, 1996. https://patents.google.com/patent/CA2168504A1/en?q=(preservative)&assignee=Andersen+Corporation&oq=(preservative)+assignee:(Andersen+Corporation)&page=1 (accessed 2024-06-25).

[14] Albrecht, S. D. Versatile Hybrid Window System. US10550624B2, February 4, 2020. https://patents.google.com/patent/US10550624B2/en?q=(windows)&assignee=sierra+pacific&oq=sierra+pacific+windows (accessed 2024-06-25). Vassilev, A.; Header, G. A. Cladding System for Glazed Doors and Windows. US9725946B1, August 8, 2017. https://patents.google.com/patent/US9725946B1/en?q=(aluminum-clad+window)&oq=aluminum-clad+window (accessed 2024-06-25).

[15] Weiss, D. J. Clad Window Frame with Improved Sealing. CA2524843A1, July 20, 2006. https://patents.google.com/patent/CA2524843A1/en?q=(window)&assignee=Andersen+Corporation&page=7 (accessed 2024-06-25).

[16] CHROMIUM (VI). Pharos. https://pharos.habitablefuture.org/chemicals/2007314 (accessed 2024-06-25).

[17] PVDF-Coated Aluminum Cladding. Pharos. https://pharos.habitablefuture.org/common-products/2294229 (accessed 2024-06-25).

[18] Ann Blake; Mark Rossi. Plastics Scorecard, 2014. https://www.cleanproduction.org/resources/entry/plastics-scorecard-resource (accessed 2021-07-12). 

[19] For instance, dimethyltin bis(2-ethylhexyl mercaptoacetate) CAS # 57583-35-4 is “Suspected of damaging fertility or the unborn child” and “may cause damage to organic through prolonged or repeated exposure” per the European Chemicals Agency Classification & Labeling Inventory.

Last updated: November 08, 2024