said by nunya:We already have a number of propane appliances, but the draw at full load for a 20kw generac is much larger than our 45 gallong tank could supply. Even if the tank could keep up, it'd be dead in about 4-7 hours depending on load.
OP, if your house is still in the construction phase you should probably do some quick research on propane appliances if you are going to have a tank installed anyway.
Quite often, even propane beats operating costs of electric heating appliances. Electric resistance heat is very inefficient.