Windows, Doors & Insulating Glazing Patents: Top Filers 2026
- Filing has cooled sharply. activity peaked at 13 records in 2017 and has since fallen to a single record by 2026, with the 2022 midpoint at just 1.
- The top 5 assignees hold 68.8% of the field. 75 of the 109 records in scope trace to just five companies, rising to 92.7% once the top 10 are counted.
- Nearly every record sits in E06B. doors, windows and shutters classification, while glass composition, laminates and building-structure claims trail far behind as thinner, more open branches.
What this landscape covers
This dataset tracks 109 published patent families filed between 2015 and mid-2026 that combine insulating glass unit, window system and door system building claims with technical language on U-value, warm edge spacer design, argon retention, condensation resistance or acoustic performance. The scope is deliberately narrow: it isolates the performance-engineering layer of fenestration hardware rather than general glazing or architectural design filings, and it is anchored to IPC E06B3, C03C27 and E06B7 — the classifications covering windows/doors, glass-to-metal sealing and window/door hardware respectively.
Because publication typically lags filing by around 18 months, the 2025 and 2026 figures in any trend line understate real filing activity; treat the most recent one to two years as a floor, not a ceiling.
Filing trend and technology composition
Two views of the same 109 records: how filing volume has moved year over year, and how those records distribute across IPC subclasses.
A 2017 peak followed by a steady decline
Filings reached their high point at 13 records in 2017, fell through the following years, and sat at just 1 record by the 2022 midpoint and again by 2026. This is a flat-to-declining trend, not a market in early growth, though the final one to two years are undercounted due to publication lag.
Concentration in E06B, with thinner adjacent branches
Every record in scope carries an E06B classification (doors, windows and shutters) by construction of the search. Beyond that base, glass and enamel compositions (C03C) appear in 11.9% of the 109 records, layered products and laminates (B32B) in 7.3%, and building structures (E04B) in 6.4%. Smaller shares in displaying/signs (G09F), refrigeration (F25D), shop fittings (A47F) and mixing (B01F) mark narrower, more opportunistic overlaps rather than core claim territory.
Shares are the percentage of the 109 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Windows, Doors and Insulating Glazing with Eureka
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Try EurekaThe most-cited prior art in this field
US8866590B2 — Insulating glass unit with an electronic device and process for its production
A sealed insulating glass unit comprises two glass sheets held apart by a spacer, optionally with a sealant between the edges of the glass sheets outside the spacer. The insulating glass unit contains an electronic device, having information relating to the origin, manufacture and/or properties of the insulating glass unit capable of being read from the device by means actuated from outside the insulating glass unit. The device is embedded within the spacer or sealant so that it is concealed within the insulating glass unit.Filed by Bystronic Lenhardt, granted 2014-10-21 — this claim family sits at the intersection of spacer design and embedded electronics, a combination that recurs across the co-assignee network in this space.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6238755B1 | Insulating glass units | 174 |
| 2 | US5270084A | Insulating glass unit | 129 |
| 3 | US7281561B2 | Multi-layered film window system | 84 |
| 4 | US20060265979A1 | Anti-fog refrigeration door and method of making the same | 63 |
| 5 | WO2007137719A1 | Insulating glass unit with an electronic device and process for its production | 50 |
| 6 | US20120009366A1 | Chemically Curing All-In-One Warm Edge Spacer And Seal | 24 |
| 7 | WO2010111174A1 | Chemically curing all-in-one warm edge spacer and seal | 21 |
| 8 | EP2963226A1 | An insulating glass unit and a process for manufacturing an insulating glass unit | 19 |
| 9 | US7851034B2 | Embedded vacuum insulating glass unit, and/or method of making the same | 19 |
| 10 | WO2007035801A2 | Anti-fog refrigeration door and method of making the same | 16 |
Citation counts accumulate over time, so older filings are structurally favoured; treat this table as a map of influential prior art, not of current commercial importance.
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Reading volume, concentration and citation data together points to a mature, consolidated claim landscape rather than an emerging one.
Filing has not recovered from its 2017 peak
The count of 13 records in 2017 is the high point of the entire window; by the 2022 midpoint filings had dropped to 1 and stayed there through 2026. Publication lag means the last year or two is undercounted, but the multi-year decline predates that effect.
A small group of assignees controls most of the field
Five companies account for 75 of the 109 records in scope, and the top 10 account for 101 — 92.7% of the field. With 43 ranked companies total, this leaves a long tail of single- or few-filing entrants competing for the remaining share.
Claims cluster on hardware, not glass chemistry
Every record touches E06B doors/windows/shutters classification by design of the search, but only 11.9% add glass or enamel composition claims (C03C) and 7.3% add layered-product claims (B32B). The bulk of the activity is mechanical and structural, not materials science.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to windows, doors and insulating glazing, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Technoform Glass Insulation Holding | Pellini S.p.A. | 15 |
| Dow Silicones Corporation | Bystronic Lenhardt GmbH | 4 |
| Dow Silicones Corporation | Dow Corning Corporation | 2 |
| Dow Silicones Corporation | DOW CORNING GMBH | 2 |
| Dow Silicones Corporation | WOLF ANDREAS | 1 |
| Dow Silicones Corporation | THOMAS RICHARD HENRY | 1 |
| Dow Silicones Corporation | SHERMAN ANGELA L | 1 |
| Dow Silicones Corporation | SCHULER PETER | 1 |
Only 10 co-assignee pairs appear across the dataset, and the strongest pairing accounts for 15 shared records — a level of collaboration limited to a small number of corporate-affiliate relationships rather than a broad industry network.
Who holds the ground
The assignee ranking covers 43 companies across all 109 records in scope. It is a short, top-heavy list: the leader holds 18 records, the fifth-place company holds 11, and by tenth place the count has fallen to 4 — after which the field thins into single-digit filers.
One assignee sets the pace
The top-ranked company holds 18 of the 109 records in scope, well ahead of the rest of the field. That lead, combined with the top 5 controlling 68.8% of all records, suggests most of the core spacer, sealing and hardware claim territory is already staked out.
A tight cluster just below the leader
Fifth place holds 11 records — still substantial, and part of a group of five companies that together account for 75 records. This mid-tier is where most of the competitive filing activity has actually happened.
Volume drops off quickly after the top 10
By tenth place the count is down to 4 records, and the top 10 combined already reach 92.7% of the field. The remaining 33 ranked companies split a small residual share, mostly as single-filing entrants.
| Assignee | Recent year | YoY |
|---|---|---|
| Dow Silicones Corporation | 0 | — |
| Technoform Glass Insulation Holding | 0 | — |
| Pellini S.p.A. | 0 | — |
| Guardian Glass LLC | 0 | — |
| PDS IG HLDG LLC | 0 | — |
| Apogee Enterprises Inc. | 0 | — |
| AGC Flat Glass North America Inc. | 0 | — |
| Apogee Enterprises Inc. | 0 | — |
Where to take this analysis
The dataset points to a consolidated, slowing field with specific narrow openings rather than broad white space.
Check freedom-to-operate against the top 10
With 92.7% of records held by ten companies, any new filing in core spacer, sealing or hardware claims should be checked against that group's portfolios first.
Run a freedom-to-operate searchProbe the under-claimed branches
Glass-composition and laminate-structure claims sit well below the core E06B share, suggesting narrower openings for materials-focused approaches to U-value and condensation resistance.
Explore adjacent IPC classesTrack the mid-tier for consolidation signals
A cluster of companies each hold meaningful but not dominant share; shifts here via acquisition or licensing would reshape the competitive picture faster than new filing activity.
Monitor assignee activityCommon questions on this landscape
The assignee ranking for this dataset covers 43 companies across 109 records, and it is top-heavy: the leading company holds 18 records, fifth place holds 11, and the top 5 combined account for 68.8% of all 109 records in scope. By the tenth-ranked company the count has fallen to 4 records, and the top 10 together reach 92.7% of the field. This means a small group of incumbents controls most of the documented claim territory in warm-edge spacer, sealing and window/door hardware technology.
Filing activity peaked at 13 records in 2017 and has declined since, reaching just 1 record by the 2022 midpoint and again in 2026. That is a flat-to-declining trend over the period covered. Publication typically lags filing by around 18 months, so the most recent one to two years will always look thinner than they eventually turn out to be, but the multi-year decline from the 2017 peak predates that lag effect.
Every record in this dataset carries an E06B classification (doors, windows and shutters), since that is the anchor of the search scope. Beyond that base, glass and enamel composition claims (C03C) appear in 11.9% of the 109 records, layered products and laminates (B32B) in 7.3%, and building structural elements (E04B) in 6.4%. Smaller overlaps with displaying/signage, refrigeration, shop fittings and mixing classifications mark narrower cross-application uses rather than core development areas.
The clearest openings sit in branches with low record counts relative to the dominant E06B hardware classification, notably glass-composition chemistry approaches to U-value and condensation resistance, warm-edge spacer material formulations, and embedded-sensor integration within spacers or sealants. Co-filing across companies is also rare in this dataset, with only 10 co-assignee pairs recorded, suggesting most innovation has happened within single corporate portfolios rather than through joint development. A new filing with a narrow, well-drafted claim in one of the thinner IPC branches is more likely to clear prior art than a broad claim in core E06B hardware.
US8866590B2, assigned to Bystronic Lenhardt and granted in 2014, covers a sealed insulating glass unit with an electronic device embedded in the spacer or sealant, used to store and allow retrieval of information about the unit's origin, manufacture or properties. It matters because it sits at the intersection of two claim areas covered separately elsewhere in this dataset — spacer design and embedded electronics — and represents a concrete pattern for combining hardware and data-carrying functions in a glazing unit. Anyone drafting claims involving smart or trackable insulating glass units should review this filing directly before assuming the combination is open.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.