semi full time no generator

pnichols wrote:

Hitech wrote:
Why get a genset? You'll get more heat per gallon running the motorhome's engine, and pay less in maintenance per hour run. Gensets are inefficient sources of heat.

Jim,

You make a good point ... under certain conditions.

Our Ford V10 supposedly consumes about 0.7 gallons per hour idling and it's cab heater can completely heat our (small) Class C motorhome. Our Onan built-in generator can only power about two and a half ~5000 BTU electric heaters while consuming about 0.5 gallons per hour ... so probably the idling V10 wins on fuel usage efficiency to heat our motorhome.

However:

1) Diesel engined motorhomes probably shouldn't be idled nearly as much as can be the Ford V10 (i.e. I believe that E350/E450-based emergency vehicles sometimes idle their V10's for hours and hours.).

2) I'm not sure my Onan generator costs more me more $$ for service than the V10 does ... far less oil to change and less $$ for an air cleaner with the Onan.

FWIW, I do consider that if required and not considering efficiency, our MH has three interior heating methods: Idling V10 w/cab heater, or propane furnace, or built-in generator powering electric heaters.

Exactly. The cutaways are designed for extended idling such as in emergency vehicle service. The engine service visit cost is the same order of magnitude for a genset as a gas vehicle engine, but the interval in hours between engine service on an e series engine is far longer than on a genset. And the vehicle engine lets you extract both heat from the engine AND motive force to drive an alternator.

Burning propane has a much higher efficiency, but when more total BTUs are needed the next best system in a Motorhome is the engine. Genset is last resort for heat generation in terms of BTUs generated per cost to generate them.

Jim