We called around 9AM on a Friday because our furnace would not turn on and we were getting pretty chilly. Sierra Air guaranteed same day service and was incredibly professional, with wonderful communication! Dago, the tech who came that same afternoon, was a Godsend! He explained the issue, fixed it and recommended adding an awesome air cleaner since we live in a very dry and dusty area. He was cordial, funny, very knowledgeable, and seemed to genuinely have our best interests in mind (not just trying to "get a sale"). Once the air cleaner was installed we could immediately smell and feel the difference! Amazing! He was also nice enough to offer to return if anything went wrong/stopped working/ or if we ended up not experiencing all the benefits the new air cleaner offered and promised. Dago, thank you for all of your help, and truly offering exceptional customer service! We will definitely be referring any friends or family that need/want a cleaner and healthier home to Sierra Air!