Hi. I too live in an area that has no natural gas. My primary heat is oil.I use propane for hot water (40 gallon), stove(totally agree with you on cooking),clothes dryer and I've got the gas grill tapped in too.The newest (and best) addition is a gas fireplace, which when properly circulated (I'm still working on this) goes a long way to heating our 2200 sq.ft house.I live in upstate New York and my advice would be to shop for price and go with a company that offers a lock in price.My contract lasts a year.The propane company owns the tank and I don't believe there is any deposit.They will determine which size tank you'll need by the amount of propane they will estimate your usage to be,which of course will be determined by how you decide to heat ,etc.My tank is an upright 100 gallon,and the company supplied a Tank Guard monitoring system which electronically tells them when to deliver.I have been very happy with my current setup. Shop for a reputable company and they will help you out and answer all of your questions. Keep in mind,one of the best ways to save energy dollars is by zone heating. This does'nt necessarily mean fancy ductwork and dampers. It might mean that you have a room that you dont use as much that you have a small electric heater in,while keeping the primary heat off. Some might say electric is bad advice,and yes it's very exspensive.It is also 100% efficient,there is no waste.Also gas companies crow about how much more efficient natural gas is than oil heat. This is very misleading in that oil provides a much higher BTU rating per unit than oil.The knock on oil is that it burns dirtier than gas,necessitating yearly cleanings. One question for you,why an 80 gallon water heater? My 40 gallon more than provides enough,even when the kids were home or we have guests.It has an excellent recovery time,we never lack for hot water.