All commercial and military aircraft fly with the pitot heat on - it's SOP. In any case, most commercial and military aircraft are inevitably going to fly above the zero deg isotherm.
You don't have an electricity bill to pay, so why not go belt and braces and switch it on before you get airborne. You never know what atmospheric conditions you may encounter, and, as Deano777 says, better to put it on than to wish you had put it on.