Summer-Winter Hookup

[robz01]

I have a summer-winter hookup on my oil fired boiler which heats the water. In this day of high oil prices what is the most efficient temperature differential I should set for boiler to turn on to heat the water back up again?
a 10 degree differential or 20 degree differential. I understand that when I turn my thermostat on to heat my house in the winter this temperature differential doesn't matter. But in the meatime what is the preferred or most efficient setting?

Thanks for your help.

[flange]

With an oil burner, and any burner for that matter, the efficiency is greatest when the system experiences long run times. Therefore, in theory a twenty degree delta would be preferable. Realistically most boilers are oversized and this shouldnt be a problem except in severely cold weather. I keep mine at thirty until its gets in to the single digits, which it rarely does around here anymore. For me its no biggie to simply adjust it at will.