On April 20, Richard Isom brought the civil antitrust action in the U.S. District Court, Eastern District of Michigan, on behalf of himself and “all persons and entities who directly purchased HVAC Equipment manufactured by Defendants in the United States beginning at least as early as January 1, 2020, through the present.”

Trane, Lennox, Carrier, Rheem, Daikin, Bosch, and AAON are listed as defendants, and the suit claims that these seven OEMs control over 90% of the $31.26 billion HVAC equipment market in the U.S.

The complaint argues that the pricing pattern from these OEMs broke from historical norms beginning in 2020, suggesting there was coordination behind the price increases.

According to the complaint, HVAC equipment prices did not follow the CPI and the producer price index increases that other major household appliances did after 2020. Instead, HVAC equipment rose by about 53.5% from January 2020 to present, compared to roughly 29.7% for CPI and 30.8% for major appliances.

The filing notes near-record profit performance for Lennox, Carrier, Daikin, Trane, and AAON during this period, including margin expansion, even as cost pressures moderated.

A referenced preliminary regression analysis, controlling for 19 independent variables, found an estimated 8% overcharge above competitive levels, which the complaint says translates to billions of dollars.

While the OEMs publicly cited factors like tariffs, the pandemic, and issues with raw materials to explain the increases, the suit argues that the public explanations for those increases do not hold up.

“When customers complained, Defendants had their story ready: COVID-19 disrupted supply chains, new efficiency standards required expensive redesigns, and federal law forced a costly refrigerant transition. These were not honest explanations; they were cover,” court documents state.

As an example, the complaint points to the new SEER2 energy conservation standards, which set minimum efficiency requirements for new HVAC Equipment sold beginning on January 1, 2023, and were published in the Federal Register on January 6, 2017.

“Defendants, therefore, had at least six years to develop compliant equipment. Yet, Defendants still blamed the new standards for price increases,” the suit states. “For example, on its website, Lennox claimed, ‘The new air conditioners will be approximately 10%-15% more than [outgoing models]. The new heat pumps will be approximately 20%-25% more than [outgoing models]. This price increase is due to a more efficient compressor, a more efficient fan motor, a larger coil and cabinet size, and a higher refrigerant charge to achieve the higher efficiency.’”

The nature of the HVAC market itself made the alleged coordination efforts easier, the suit claims.

Residential HVAC Equipment prices are broadly uniform across the OEM brands, the suit says, typically falling between $4,000 and $15,000 at the manufacturer level, with variation driven primarily by efficiency ratings, capacity, and features rather than by manufacturer identity.

“A 16 SEER2 heat pump from Trane is priced comparably to a 16 SEER2 heat pump from Carrier or Lennox. Commercial HVAC Equipment follows the same pattern at higher price points, ranging from $5,000 to over $100,000 depending on system type and application, with pricing similarly consistent across Defendants for comparable equipment,” the suit states.

“This pricing uniformity exists in a market where buyers have no practical alternative to purchasing,” the suit states. “When a furnace or air conditioner fails, the owner must typically replace it, regardless of cost. Demand does not decline meaningfully when prices rise. That combination—uniform pricing across competitors and captive demand—gave Defendants both the means and the motive to coordinate.”

To support the price-fixing theory, the suit also references a number of public statements and quotes from senior manufacturing executives that suggested that cutting prices would not result in a manufacturer gaining a larger share of the market via competition. One such quote is from Lennox CFO Michael Quenzer saying the industry had “been disciplined for the past several years” and that the company would keep increasing prices because “others have generally been as well,” plus his statement that taking prices away “does not win market share.”

Beyond pricing, the suit argues OEMs restricted output rather than competing against each other for market share.

“When demand softened, they coordinated to restrict supply, ensuring that lower volumes would not lead to lower prices. As 2025 progressed, Carrier repeatedly claimed that it was reducing inventory to support prices. In January 2026, Trane’s CFO revealed that the company had ‘reduced factory production days by one-third’ and assured competitors publicly: ‘I don’t want anyone to think that pricing is coming down in that market.’ Lennox’s CFO promptly confirmed that Lennox would follow: ‘We’re gonna reduce some production in the first quarter, keep our inventories flat.’ In a competitive market, a manufacturer that cuts production by a third loses customers to rivals. That Carrier, Trane, and Lennox did so openly is explicable only if each company understood that their competitors would hold the line.”

According to court documents, the defendants used two mechanisms to support their price fixing conspiracy: first, the Air-Conditioning, Heating and Refrigeration Institute (AHRI), and second, ACHR News. Neither organization is named as a defendant.

The suit alleges that the manufacturers used AHRI as a private exchange for nonpublic market data, and that manufacturers are required to contribute confidential data to get access to reports and dashboards that showed market performance, inventories, shipments, and other related metrics.

Additionally, the suit claims that the OEMs used ACHR News, which publishes HVAC price increases, not merely to announce price increases, but as a means to communicate with each other out in the open — the precise percentage of an upcoming price increase would be published, along with the specific product lines affected, and the exact effective date, “typically weeks before implementation.”

“In a competitive market, that level of advance specificity is irrational,” the suit states. “A manufacturer that broadcasts a 9% increase three weeks before it takes effect risks losing customers to competitors who hold steady or undercut. Yet after COVID, across six years and more than 40 published price increases, the exposed firm was consistently rewarded rather than punished as competitors matched or exceeded the announced increase, usually within days, at nearly identical percentages, through the same publication.”

Isom is demanding a trial by jury and seeks “to recover treble damages and the costs of this suit, including reasonable attorneys’ fees, against Defendants for injuries sustained by Plaintiff and members of the Class resulting from Defendants’ violations of Section 1 of the Sherman Act, 15 U.S.C. §1, and to enjoin further violations.”