Dave from TwinTech was very knowledgeable, professional and thorough in the buying process. He helped us to identify the best furnace for our home and our budget. When we needed a new filter a year later and seemed to have a problem finding the right one, I called Dave up and he delivered a filter to me the next day! The cost was on par with other retailers, but it was this unexpected personal service that really was impressive. The furnace? Works like a charm.