Cedar Lane Tech Inc v. Broan Nutone LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Cedar Lane Technologies Inc. (Canada)
  • Defendant: Broan-NuTone LLC (Delaware)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 3:25-cv-965, W.D. Wis., 11/24/2025
• Venue Allegations: Venue is alleged to be proper because Defendant maintains an established place of business in the Western District of Wisconsin.
• Core Dispute: Plaintiff alleges that Defendant’s ventilation products infringe a patent related to methods for retrofitting existing ventilation systems with automated air quality sensor controls.
• Technical Context: The technology concerns HVAC (Heating, Ventilation, and Air Conditioning) systems that automatically activate high-speed fan operation upon the detection of specific airborne contaminants.
• Key Procedural History: The complaint does not reference any prior litigation, licensing history, or post-grant proceedings involving the patent-in-suit.

Case Timeline

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

U.S. Patent No. 7,632,178 - "Ventilation blower controls employing air quality sensors"

• Patent Identification: U.S. Patent No. 7,632,178, “Ventilation blower controls employing air quality sensors,” issued December 15, 2009 (’178 Patent).

The Invention Explained

• Problem Addressed: The patent describes prior art ventilation systems as often relying on manual wall switches or simple occupancy detectors, which can be inefficient. For example, users may forget to turn blowers on or off, and occupancy-based systems may activate a fan unnecessarily or turn it off before high humidity or odors are cleared ('178 Patent, col. 2:6-17). Furthermore, retrofitting such systems to respond automatically to specific contaminants like carbon monoxide or smoke was not straightforward ('178 Patent, col. 2:40-51).
• The Patented Solution: The invention provides a method for retrofitting an existing ventilation system that has a "Remote Switch connection" for high-speed operation. The method involves adding one or more air quality sensors (e.g., for smoke or carbon monoxide) and a relay. The sensors are wired in parallel to the relay, and the relay's contacts are wired to the existing system's remote switch terminals. When any sensor detects a contaminant above a threshold, it triggers the relay, which in turn signals the main ventilation unit to enter a continuous, high-speed mode to evacuate the contaminated air ('178 Patent, col. 2:51-58, Fig. 3).
• Technical Importance: This approach allows for the upgrade of existing ventilation systems to add intelligent, automated air quality control without requiring replacement of the entire system ('178 Patent, col. 2:33-40).

Key Claims at a Glance

• The complaint alleges infringement of "one or more claims" and refers to "Exemplary '178 Patent Claims" identified in an attached exhibit, but does not specify claim numbers in the body of the complaint (Compl. ¶¶11, 16). The patent contains one independent claim, Claim 1, which is a method claim.
• The essential elements of independent Claim 1 are:
  • Providing an existing ventilation system having fans and at least one remote switch terminal for setting a high speed mode of operation.
  • Adding a relay to the system.
  • Inserting at least one air quality sensor in a specific location.
  • Connecting the relay's contacts to the remote switch terminals.
  • Connecting the air quality sensor(s) in a parallel network to the relay, such that detection of an "abnormal air quality condition" activates the relay to set the high speed fan operation.

III. The Accused Instrumentality

Product Identification

The complaint does not name specific accused products in its text, instead referring to "Exemplary Defendant Products" that are identified in charts within an attached exhibit (Compl. ¶¶11, 16).

Functionality and Market Context

The complaint does not provide sufficient detail for analysis of the accused products' specific functionality. It makes the conclusory allegation that the "Exemplary Defendant Products practice the technology claimed by the '178 Patent" and "satisfy all elements of the Exemplary '178 Patent Claims" (Compl. ¶16).

IV. Analysis of Infringement Allegations

The complaint incorporates infringement claim charts by reference to Exhibit 2, which was not provided with the complaint pleading (Compl. ¶17). The complaint’s narrative infringement theory states that "the Exemplary Defendant Products practice the technology claimed by the '178 Patent" (Compl. ¶16). The complaint alleges that Defendant directly infringes by, among other things, having its employees "internally test and use these Exemplary Products" (Compl. ¶12). No probative visual evidence provided in complaint.

Identified Points of Contention

• Scope Questions: Claim 1 is directed to a "method of retrofitting an existing ventilation system." A primary question will be whether Defendant’s alleged acts of making, using, or selling ventilation systems constitute performing this multi-step retrofitting method. The allegation that Defendant’s employees "internally test and use" the products (Compl. ¶12) may be Plaintiff's basis for direct infringement, raising the question of whether such testing meets all limitations of the claimed method.
• Technical Questions: A potential dispute may arise over whether the accused products contain the specific components recited in the claim. For example, a court may need to determine if the accused products' control architecture includes a component that functions as a "relay" and interfaces with a "remote switch terminal," or if they employ a more integrated digital control system that does not map onto these claim elements.

V. Key Claim Terms for Construction

"retrofitting an existing ventilation system"

• Context and Importance: This phrase appears in the preamble of Claim 1 and defines the overall process being claimed. The infringement analysis will depend on whether Defendant's alleged activities (e.g., selling or testing a new, complete system) can be characterized as "retrofitting" an "existing" one.
  • Evidence for a Broader Interpretation: The specification states that some ventilation systems are "especially easy to retrofit" with the invention, suggesting the term applies to the act of upgrading a system with new sensor capabilities ('178 Patent, col. 2:33-36).
  • Evidence for a Narrower Interpretation: The specific steps recited in the body of Claim 1—"adding a relay," "inserting... a sensor," and "connecting contacts"—imply the modification of a pre-existing, operational system, not the de novo assembly or installation of a new one.

"remote switch terminal"

• Context and Importance: This term is critical as it defines the specific interface point on the "existing ventilation system" that the patented method utilizes. If the accused products lack a structure that meets this definition, there may be no literal infringement.
  • Evidence for a Broader Interpretation: The patent's background describes systems with a "Remote Switch connection," which could be argued to encompass any interface that allows for external control of the fan speed ('178 Patent, col. 2:36-37).
  • Evidence for a Narrower Interpretation: The specification’s description of wiring relay contacts "to the Remote Switch interface terminals" suggests distinct physical connection points designed to receive a simple switch closure, a feature that may be absent in more modern, digitally controlled systems ('178 Patent, col. 2:56-58).

VI. Other Allegations

• Indirect Infringement: The complaint alleges inducement, stating that Defendant distributes "product literature and website materials inducing end users and others to use its products in the customary and intended manner that infringes the '178 Patent" (Compl. ¶¶14-15).
• Willful Infringement: The complaint does not use the term "willful." It alleges that the service of the complaint itself provides "actual knowledge of infringement" and that Defendant's continued infringement thereafter is done "Despite such actual knowledge" (Compl. ¶¶13-14). These allegations may form the basis for a claim of post-suit willfulness.

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

• A central issue will be one of infringement theory: Given that the sole independent claim is for a "method of retrofitting," can Plaintiff prove that Defendant directly infringes by "internally test[ing]" its products, or must it rely on a theory of indirect infringement based on the actions of Defendant's customers who may perform the claimed method?
• A key question will be one of claim scope: Can the terms "relay" and "remote switch terminal," which are rooted in the context of modifying older electromechanical systems, be construed to read on the potentially integrated, digital control architectures of modern ventilation products?
• An evidentiary question will be one of factual basis: As the complaint lacks specific factual allegations detailing how the accused products operate, a primary focus in discovery will be establishing the technical reality of the accused systems and comparing that reality to the limitations of the asserted claims.