Thinking of getting one of these for my house and maybe one for my office. Every time it rains the lights go off at my office, it want run the AC 120 tons, but at least the phones and computers will work.

Pros and cons, different models etc.

Curtis

Natural gas is the only way to go. Diesel will only get you so far before it has to be refueled. Natty will run cleaner and you won't have to worry about how much fuel you have on hand. You will pay a little more for a natty gen set than a diesel. Olympian makes a nice product. Buy bigger than you need and have a automated switching system with a constant power supply so there is NO interuption in service during the transition.

It was going to be nat gas, with an automatic switch.

Can I run a small AC unit (2tons) ?

CM

You'll have to add up the wattage for every piece of equipment you want to run. You'll also have to get the wattage used by each piece at turn on or start up. Large appliances like refrigerators, washer/dryer, dishwasher, A/C units, air handlers, water heater, etc. pull more current to start than they use at any other time. You have to take all that into consideration when you purchase a generator.

40 Kw!!!

I run a Generak 15k unit, as it won't run my whole house it runs both our 2ton and 3ton ac units, the freezers ,refrigerators, and essential lights.
She kicks on 10 seconds from the time our power goes off and has runs 48+ hrs at a time on natural gas.
It was a good investment for us!

You can run anything that you want. It's all a matter of how much you want to spend. I just specified a 600kw Kohler unit for a new building. http://www.kohlerpowersystems.com/pdfs/g5235.pdf

This is a 2000kw that I got to see installed years ago. This one was inside the building on the second floor. You could feel it rumbling 100' away. v16, 4 valves per cylinder, twin superchargers, twin turbos, twin oil pans, 4 exhaust manifolds, the electric fan was 6' in diameter. The wild thing is that the unit wasn't making it's full wattage, so the engine was torn down on site and rebuilt. The pistons were just a little smaller than a #10 tin can. http://www.kohlerpowersystems.com/pdfs/g5236.pdf

I'm installing one at a house I'm building. It's a 12000sf home & the owner wants everything including the pool & spa to work if the power goes out.
It's a custom Onan/Cummins 140KW unit which I'm sure will work for you. Should I order another? It only cost about 100k including the two 2000 gal propaine tanks. The $38,000 underground vault would be an extra if you want it.
The transfer switch is about as big a a Volkswagon

Nat gas will give you problems, more crap to fail, plugs, cap, wires. must go industrial to eliminate the BS.

I am a dealer for ONAN, CAT, KOHLER, DETROIT, KATOLITE, BALDOR AND SDMO.

if you want some help just PM or ask,

A typical house 200 amp service can be supported for less than 20K

or you can just turn on all the things that you may be running at the same time and then put an amp clamp around your phases to check total draw.