Hi Pat - It is a very good idea to have a CO detector in or near the sleeping quarters if you have a Diesel-fired heating plant aboard. We have a Xintex unit mounted low in the companionway as well as a fire/smoke/CO detector on the overhead in the master stateroom. This latter unit goes off regularly if we leave the starboard port open while underway (water-cooled exhaust thru the side just ahead of the master stateroom). So I guess there's enough CO in the engine exhaust to set it off. Regards, John "Seahorse" > I am sure the need for air conditioning in the pacific N.W. is not very high, and you can go with a DIESEL forced air heating system which is clearly another reason for diesel power. **************It's Tax Time! Get tips, forms and advice on AOL Money & Finance. (http://money.aol.com/tax?NCID=aolcmp00300000002850)