I can't remember the amperage, but, in winter it will run the Furnace, water pump, lights and tv, even the computer. The new one is supposed to put out even more, yet be more energy efficient. (it runs on propane) Which supplies our heating, hot water and cooking needs.
Never mind, I looked at the quote, it's a Kohler Model 12RES, rated at 12 Kw,KVA producing 50 amps at 120/240 volts phase 60 Hz. Except for the Ice storm of 1998, we have not lost power for more than 12 hours, BUT, we do lose power for several hours at least 3-6 times a year.
Having a generator hardwired to our house has been a lifesaver. The original was installed 3 months before the Ice storm and we lost power for 3 days. AND we were lucky, most others lost power for 1-2 weeks!