I have a Gas generator and a 10 circuit transfer switch. My gen is 5500 watt and only used about 2300 watts everytime i used it in the winter. It's gas and never an issue. Did you ever have an issue with your lawnmower? Just put Stabil in and run it a few times a year. I have never had a Gas station run out of fuel or power around here. My gen runs about 11-12 hours at half load. A propane runs about 8hrs. If you need propane at 2am where r u going to get it? I turn off the gas and let it stall out everytime it's used. I have had this setup since the 2008 ice storm. ask the electrician about an interlock switch they seem to be the go to these days...I just have 3 , 5 gallon emptys incase ....My basement is finished so a frozen pipe wouldnt be good...There is a few 5500 watt gens on craigslist NH for sale, ones a Briggs storm responder 5500 watt and a craftsman 5600 watt for around 450ish.