Under the new arrangement, new members can choose to join just the national HVAC sales group. The setup has boosted enrollment more than 60 percent, the association said. Specific membership numbers were not released.

"Contractors want an organization that is committed to serving them nationwide, and they don't want to have to jump through hoops to support it," said Phil London, the ACCA’s 2015-2016 chairman. "Clearly contractors wanted open membership, because the response has been tremendous. In fact, in addition to the new members, a lot of former members are re-joining the association because they appreciate the flexibility and freedom of choice that our new membership program offers. Freed from the chains of administering complicated dues, our association staff are focused on serving members, representing contractors, and developing new member benefits."

State chapters, now known as “allied contracting organizations,” include Air Conditioning Contractors of Ohio, Conditioned Air Association of Georgia, Michigan Air Conditioning Contractors Association and Southern Nevada Air Conditioning Refrigeration Contractors Association.

ACCA President and CEO Paul Stalknecht said membership for HVAC sales companies in markets with state groups offer additional benefits.

"It's important that contractors have effective, professional representation at the state and national level," Stalknecht said. "We encourage all of our members who operate in the states served by our ACOs to support those organizations as well as ACCA."

The full list of state groups is here.