Just a heads-up… IDK know how old your furnace is but my high efficiency 2016 furnace won’t run off my Honda… fussy electronics. Fridges have been electronic for decades and it works fine.
The old farm was all electric and I wired a 25kw pto driven gen in dads barn, in the mid 70s. Wire gauge was right and I made sure the bldgs and the gen had common gnds and neutral. REA put a manual disconnect on the main line and they let him do manual switching. Power was out for 4 days the next winter and dad said his poor old M went thru 50 gallons of gas a day.
