I thought that it was illegal to sell to the public hvac systems without installing them. I am a HVAC contractor and it is not right that the public can go on line to ebay or craigslist and buy any system they want and they are trying to install them there self. If I am not mistaking, the seller is responsible anybody who buys the unit, not being cfc certified. I dont have my cfc book with me and thought someone could help me on this issue. If anyone has any facts to add I would appreciate it.