Greg, one thing you might want to check is how old your oil furnace is. The reason i ask is small generators tend to have "dirty" electricity. If you have a newer furnace, even though it is an oil burner, it might have electronics in it that are susceptible to damage from voltage or phase variation that is present in a small gen set. Old oil burners will run just fine on a generator. If in doubt check with your service tech. or the manufacturer.