Comfort Systems USA Ohio/Kentucky is an operating company of Comfort Systems USA; a publicly-traded company on the NYSE with 48 operating companies and over 70 locations throughout the United States and Puerto Rico. Comfort Systems USA is the nation’s largest full service HVAC and facility automation systems contractor. Mechanical Contracting Our collaborative approach leads to energy efficient, cost effective building solutions. Learn how we can help. Service & Maintenance Proactive maintenance reduces operating costs and extends the useful life of equipment and systems. Learn how we can help. Automation & Security Integrated building automation & security systems provide the most energy efficient buildings. Learn how we can help.