Callahan Roach is widely credited as the company that introduced flat-rate pricing to the HVAC industry. Founded in 1989, Callahan Roach built its reputation on publishing the most extensive and up-to-date flat-rate guides in the residential trades, covering HVAC, plumbing, electrical, pool and spa, and propane and fuel oil service. Over 60 million repairs have been priced using Callahan Roach products, and many home-warranty companies and manufacturers use Callahan Roach labor times and parts costs to establish usual and customary charges for service repairs.

Beyond the pricebook itself, Callahan Roach has always operated as a consultancy, coaching HVAC and plumbing contractors on flat-rate best practices, sales technique, and margin management. The company's content and training are specifically designed for residential home service contractors, not commercial or construction.

In September 2019, Callahan Roach and Profit Rhino merged and began operating under the Profit Rhino brand - "Profit Rhino powered by Callahan Roach." Callahan Roach content now powers the flat-rate pricebook inside Profit Rhino's modern mobile app, Housecall Pro's flat-rate feature, and ServiceTitan's enhanced pricebook content. For HVAC contractors, that means Callahan Roach content sits behind most of the major flat-rate pricebook offerings in the market today. Profit Rhino and Callahan Roach are part of the EverCommerce portfolio.