I just had my new air G73 installed and had no problems at all. It is much quieter than I thought it would be from the other reviews I read before I purchased this unit. Heat just pours out like crazy so I am sure this will solve my winter workshop blues. I rated the efficiency of the unit as good because spring has arrived and it won't be used hard till next winter. Thank you air and water this is exactly what I needed for my 24x14 shop.