DCT

1:25-cv-23275

Greentouch USA Inc v. Twin Star Intl Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Name: Greentouch USA, Inc. v. Twin-Star International, Inc., et al.
  • Case Identification: 1:25-cv-23275, S.D. Fla., 07/22/2025
  • Venue Allegations: Venue is alleged to be proper as each Defendant maintains a regular and established place of business in the district and has committed acts of infringement within the district.
  • Core Dispute: Plaintiff alleges that Defendants' electric fireplaces, manufactured by Twin-Star and sold by Lowe's and Home Depot, infringe four patents related to modular assemblies for electric fireplaces.
  • Technical Context: The technology concerns modular designs for electric fireplaces intended to reduce shipping and storage costs and to facilitate consumer assembly and design customization.
  • Key Procedural History: The complaint alleges a history of business dealings, noting that Greentouch previously supplied electric fireplaces to Lowe's and Home Depot. It references ongoing state court litigation between Greentouch and Lowe's parent company for breach of contract. Plaintiff also alleges providing pre-suit notice of the '390 and '391 Patents to Twin-Star via a demand letter, to which Twin-Star responded with a denial of infringement and an assertion of invalidity based on unidentified prior art. The complaint states that Defendants have not initiated any inter partes review or re-examination proceedings for any of the asserted patents.

Case Timeline

Date Event
2019-09-24 Earliest Priority Date for '390, '391, '409, '158 Patents
2023-04-04 '390 Patent Issued
2023-04-04 '391 Patent Issued
2023-04-17 Plaintiff allegedly informs Lowe's of issued '390 and '391 Patents
2023-04-20 Plaintiff sends demand letter to Twin-Star regarding '390 and '391 Patents
2023-05-15 Twin-Star responds to Plaintiff's demand letter
2024-01-09 '409 Patent Issued
2024-12-31 '158 Patent Issued
2025-07-22 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,619,390 - "Modular Assembly for Electric Fireplace," issued April 4, 2023

The Invention Explained

  • Problem Addressed: The patent's background section describes conventional electric fireplaces as typically being sold completely assembled, which makes them bulky and inefficient for packaging, shipping, and storing, while also limiting consumer choice in design and aesthetics (ʼ390 Patent, col. 1:26-39).
  • The Patented Solution: The invention proposes a modular fireplace constructed via a "knock/down" method, where individual components are manufactured and installed independently by the consumer (ʼ390 Patent, col. 3:62-4:12). The fireplace housing consists of separate panels (base, back, side) that are assembled by the end-user, and an electrical insert containing the heater and flame generator is then installed into the housing (ʼ390 Patent, col. 2:1-18; Fig. 2). This allows the entire fireplace system to be shipped compactly.
  • Technical Importance: This modular approach applies the logistical efficiencies of flat-pack furniture to the electric fireplace market, enabling reduced shipping volumes, lower costs, and greater flexibility for consumers to customize the final product's design (ʼ390 Patent, col. 4:18-29).

Key Claims at a Glance

  • The complaint asserts independent method claim 11 (Compl. ¶37).
  • Essential elements of Claim 11 include:
    • Providing a modular electric fireplace including a heater and a flame generator.
    • Providing at least two housing panels (from a base, back, and side panel) independently of one another, where at least one panel is "foldable."
    • Installing the housing panels into a cabinet's structural opening independently of one another.
    • Installing the heater and flame generator into the opening independently of one another.
    • Electrically connecting the flame generator to the heater.
  • The complaint reserves the right to assert applicable dependent claims (Compl. ¶39).

U.S. Patent No. 11,619,391 - "Modular Assembly for Electric Fireplace," issued April 4, 2023

The Invention Explained

  • Problem Addressed: The patent addresses the same problem as its counterpart: traditionally pre-assembled electric fireplaces are costly to ship and store and offer limited design variability for the consumer (ʼ391 Patent, col. 1:26-39).
  • The Patented Solution: The patent describes a modular electric fireplace comprising a housing and a separate electrical insert. The housing is formed from independently manufactured panels (base, back, side), and the electrical insert is specifically designed to be "fully embedded" within an opening in the base panel so that no part of the insert extends above the base panel's top surface (ʼ391 Patent, Abstract; col. 2:57-61). This configuration maintains a low profile and facilitates a "knock-down" assembly process for the consumer (ʼ391 Patent, col. 4:1-10).
  • Technical Importance: The solution provides the cost and flexibility benefits of a modular, consumer-assembled system while defining a specific spatial relationship between the functional insert and the structural base that enhances the integrated appearance of the final assembly (ʼ391 Patent, col. 9:1-6).

Key Claims at a Glance

  • The complaint asserts independent claims 1, 15, and 17 (Compl. ¶47).
  • Essential elements of apparatus Claim 1 include:
    • A fireplace housing with a base panel, back panel, and at least one side panel, each being manufactured and installed independently.
    • The base panel has a base opening.
    • An electrical insert sized to fit within the base opening.
    • The electrical insert is "fully embedded" into the opening such that "no portion" extends above the base panel's top surface.
  • Essential elements of method Claim 15 include installing a modular fireplace by providing its components (housing, logs, grate, heater, flame generator), installing the housing, installing the heater and grate, positioning the logs, and electrically connecting and controlling the components.
  • The complaint reserves the right to assert applicable dependent claims (Compl. ¶49).

U.S. Patent No. 11,867,409 - "Modular Assembly for Electric Fireplace," issued January 9, 2024

  • Technology Synopsis: This patent addresses the challenge of adapting a standardized electric fireplace heater to fit into surrounding cabinets or mantels of various widths. The invention discloses a heater assembly with interchangeable grill covers of different lengths, allowing a single core heater unit to be aesthetically integrated into different-sized structural openings, thereby increasing manufacturing efficiency and design flexibility ('409 Patent, Abstract).
  • Asserted Claims: The complaint asserts independent claims 1, 5, 16, and 27 (Compl. ¶¶55, 57).
  • Accused Features: The complaint alleges that the modular construction of the accused products, including their heater assemblies, infringes the claims related to interchangeable and adaptable components for fitting into various cabinet sizes (Compl. ¶¶54-55).

U.S. Patent No. 12,181,158 - "Modular Assembly for Electric Fireplace," issued December 31, 2024

  • Technology Synopsis: This patent, part of the same family, also targets the inefficiencies of pre-assembled electric fireplaces. The invention is a modular fireplace system where the housing components are manufactured for independent, consumer-level installation, with a specific focus on at least one of the housing panels being "foldable" to reduce its footprint for more compact packaging and shipping ('158 Patent, Abstract).
  • Asserted Claims: The complaint asserts independent claims 1, 17, and 19 (Compl. ¶¶63, 65).
  • Accused Features: The accused features are the modular, user-assembled design of the Twin-Star products, which allegedly incorporate the claimed independently installed housing panels, including at least one foldable panel (Compl. ¶¶62-63).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are numerous models of electric fireplaces and TV stands with electric fireplaces, manufactured by Defendant Twin-Star and sold by Defendants Lowe's and Home Depot under brands including "allen + roth," "Origin 21," "Kerrington," "Duraflame," "Twin Star Home," and "ChimneyFree" (Compl. ¶¶28-30). These are collectively termed the "Infringing Twin-Star Products."

Functionality and Market Context

The complaint alleges these products are sold as modular kits for consumer assembly (Compl. ¶39). End-users allegedly perform the patented methods by installing the separate housing panels and electrical inserts into the final furniture piece, such as a mantel or media console (Compl. ¶¶40, 49). The complaint positions these products as direct replacements for Plaintiff's own products, alleging that Lowe's and Home Depot began sourcing them from Twin-Star after a breakdown in their commercial relationship with Greentouch (Compl. ¶¶18, 20-22).
No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint references, but does not include, exemplary claim charts in Exhibits 5-7. The narrative infringement theories are summarized below.

'390 Patent Infringement Allegations

The complaint alleges that end-users of the Infringing Twin-Star Products directly infringe method claim 11 of the '390 Patent by assembling the products as instructed (Compl. ¶¶39-40). The theory is that the products are sold as a modular kit containing the claimed heater, flame generator, and independent, foldable housing panels. By following the provided assembly manuals and videos, consumers allegedly perform each step of the claimed installation method (Compl. ¶39). Twin-Star is accused of inducing this infringement by providing these instructions with the intent to cause the infringing acts, and of contributing to infringement by supplying a product especially adapted for this use with no substantial non-infringing purpose (Compl. ¶¶39-40).

'391 Patent Infringement Allegations

The complaint alleges that the accused products themselves directly infringe apparatus claim 1 of the ’391 Patent. The products are alleged to be modular electric fireplaces with a housing composed of independently manufactured and installed panels and an electrical insert that is "fully embedded" into an opening in the base panel (Compl. ¶¶44, 47). For method claims 15 and 17, the theory mirrors that for the '390 Patent: end-users directly infringe by performing the claimed assembly steps, and Twin-Star induces and contributes to that infringement by selling the kits with instructions (Compl. ¶¶49-50).

Identified Points of Contention

  • Technical Question: A central factual question for the '390 Patent will be whether the accused products contain a panel that is "foldable" as required by claim 11. The analysis may explore whether the panels are merely separate, rigid components for assembly or if they incorporate an integrated mechanism, such as a flexible lamination described in the patent's specification (ʼ390 Patent, col. 9:35-42), that enables folding.
  • Scope Question: For the '391 Patent, a key dispute may concern the scope of the limitation "fully embedded... such that no portion of the electrical insert extends above a top surface of the base panel." The infringement analysis will likely require a precise factual determination of the accused products' geometry and a legal construction of whether this claim language permits any de minimis protrusion.

V. Key Claim Terms for Construction

The Term: "foldable" ('390 Patent, Claim 11)

  • Context and Importance: This term appears central to distinguishing the claimed method from the assembly of conventional knock-down furniture consisting of separate, rigid panels. A finding of infringement may depend on whether the accused products' panels are merely disassembled or are constructed in a manner that allows them to be folded.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim itself does not recite a specific folding mechanism, which may support an interpretation that covers any panel capable of being bent or folded, regardless of its construction.
    • Evidence for a Narrower Interpretation: The specification discloses an embodiment where panel segments "are held together with a PVC lamination which can fold at the segments, but which looks like a single part when unfolded" (ʼ390 Patent, col. 9:35-42). A party may argue this disclosure limits the term "foldable" to panels with integrated flexible joints, rather than separate rigid panels.

The Term: "fully embedded" ('391 Patent, Claim 1)

  • Context and Importance: This term defines a precise spatial and geometric relationship between the electrical insert and the base panel. Infringement of this claim element will be a question of fact hinging on the construction of this term.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: A patentee might argue for the term's plain and ordinary meaning, which could potentially tolerate incidental or functionally insignificant protrusions of the insert above the base panel's surface.
    • Evidence for a Narrower Interpretation: The claim includes the seemingly absolute language "no portion of the electrical insert extends above a top surface of the base panel" (ʼ391 Patent, col. 14:20-22). This language may support a strict, zero-tolerance construction. The specification links this feature to the functional goal that the viewing area is "not be impeded with these bulky components," which could be used to argue against any construction that permits visible protrusions (ʼ391 Patent, col. 9:4-6).

VI. Other Allegations

Indirect Infringement

The complaint alleges both inducement and contributory infringement against Defendant Twin-Star for all four patents-in-suit. The inducement allegations are based on Twin-Star providing marketing, promotional materials, manuals, and video instructions that allegedly direct customers to assemble and use the products in an infringing manner (Compl. ¶¶39, 49, 57, 65). The contributory infringement allegations are based on Twin-Star selling products that are material components of the inventions, are especially adapted for infringing use, and have no substantial non-infringing use (Compl. ¶¶40, 50, 58, 66).

Willful Infringement

The complaint alleges Defendants had pre-suit knowledge of the patents and the alleged infringement. It states that Lowe's and Home Depot were aware of the pending patent applications as early as 2021 (Compl. ¶21). It further alleges that Greentouch provided Twin-Star and Lowe's with actual notice of the issued '390 and '391 patents in April 2023, and that Defendants continued their allegedly infringing conduct thereafter (Compl. ¶¶24-26, 37, 47).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of structural fact: do the housing panels of the accused products incorporate a "foldable" design as required by claims in the '390 and '158 patents, or are they simply a collection of separate, rigid panels characteristic of standard flat-pack furniture? The answer will likely require a detailed technical analysis of the products' construction.
  • A second central question will be one of definitional scope: can the term "fully embedded," which requires that "no portion" of the electrical insert extends above the base panel, be construed to permit any degree of protrusion? The case may turn on whether this language imposes a strict geometric boundary that the accused products fail to meet.
  • A key evidentiary question regarding damages will be the timing and nature of knowledge: what did each Defendant know about the Greentouch patents and when did they know it? Given the allegations of early notice of pending applications and formal notice letters upon issuance, the inquiry will likely focus on whether Defendants' continued conduct after notice rises to the level of objective recklessness required for willful infringement and enhanced damages.