After finding myself suspicious about another heating/cooling service provider, who 'very sadly' informed me that my heat exchanger was rusted through and that I needed to purchase a new furnace, I contacted the Angie's list service which provides consultation.
Synergy arrived an hour after I called. The men did a comprehensive testing and inspection, informed me (and had researched in advance!) of my warranty opportunities, and gave me the good news that I neither needed a new heat exchanger nor a new furnace. They were exceedingly comprehensive in their explanation, never put down the firm that tried to bilk me, and they thorough and comprehensive in presenting options. They were articulate and professional, and -- even when I offered -- they accepted no pay from me for this visit. Synergy will be my company of choice. The other company will be chagrined to learn that the firm which I lead (which has, in the past used their services) will also no longer be using them. I will recommend Synergy to our building engineers.
Source: Angie's List