What is the dba (decible rating) for a Coleman Power Mate Pulse 1800EX (Model PMC 431800.01? I have an opportunity to purchase a used unit for camping and RV use @ $220.00 is that a fair price?... Does it have the capacity to operate the A/C on a 20', 2003 Pioneer Travel Trailer? Plzzz send your findings to mmariscal1034@yahoo.com... Thank you Michael