Uh, why not just buy a natural gas unit? Not sure what warranties are worth in today's world, but I assure you converting a new one will void it immediately. Also, I believe those conversion kits (decent ones) aren't cheap. Unless there's a reason you want or need trifuel capability?

Another question is how often do you anticipate losing power and what is the impact if you do? If the previous owner used a gas genset and natural gas is available, would tend to believe outages aren't that often or extended? You mention a 10KW unit, I got along fine on a 3250 for years and recently bought a 5500 as I got a deal on it and can power more non critical but fun stuff. Do you need a genset that big? Electric heat?

Do the research, talk to neighbors, etc.

Good luck,

Ev

Just remembered there's a Generator Forum, not as active as some, but post your questions and you'll eventually get a response.

http://www.powerequipmentforum.com/forum/9-generator-forum/

I have a gasoline generator that gets used several times a year. I agree with exmar, that a natural gas generator seems more reasonable. Yes, these units are designed to be run for many hours although I have only needed mine for 5-6 hours max so far. I would normally not run it continuously to decrease engine stress and limited fuel, but I imagine you could run one continuously.

Your location is probably important. If you would need AC, you would certainly need a 7000 watt unit and I gather that you have electric heat if the Natural gas is new? In that case, the 7000 watt would probably not be sufficient either. OTOH, a 5000 watt or less unit would be fine if heat and cool are not needed.

BTW, I gather that you already have a wired in transfer switch, but I have a far cheaper and superior circuit interrupt device that prevents generator from back-feeding and at the same time allows any or perhaps all circuits to be used depending on your needs. I'm not sure that these interconnects are available for all electrical box types, but they are better all around and hardly ever mentioned.

Thanks for the feedback.
I was thinking dual fuel because it may be a while before I get the
natural gas lines actually hooked up, and plus I like the idea of gasoline as a
backup source of fuel. In terms of size,
I actually had an estimate done for a built-in backup generator that came in at
$14k installed for a 20kw unit. That’s
too rich. But I did overhear the
plumber’s calculation on how much load I had on the existing backup switchover
box and it was around 6-7kw (fridge, freezer, 3 air handlers, gas boiler, gas water
heater, kitchen lights, microwave, garage door, and a few other things). I want to check that number myself before
purchasing a unit.

I’ve asked the neighbors about how frequently outages occur
– it seems they are fairly rare (maybe every third year) but can be severe
(several times it was out for 3-4
days). That is why ultimately I would
like a natural gas fueled solution.
Gasoline would be a hassle if I’m really only using it every three
years, but when I do need it, I may need it to run for a while.