You did not mention what form of heating you use, what size Fridge, do you want to run a electric or gas cook store, do you want to run a microwave,
Do you have gas or electric heat, is there electric blowers on a home.
On that 1800 sq ft home do are you running a hot tub ? Do you want every light on ?
I have a heat pump for example but for emergancy I would turn it off and use a natural gas back up heater in my home, I have a 10,000 watt generator that runs on high speed rpm at about that 3600 RPM.
I run my single door fridge, all my lights, TV VCR and a blower for the gas heater. ( I can even run the microwave as long as the fridge does not try to kick in) A fridge will have a much higher amp draw starting up, after it starts running it is lower amp. But you can unplug the fridge for a few hours and it stays cold if you need to run some other items.
I still own them, but my old back up system, used DC lights and things