Wondering what the experience is with running the duetto on 15amps(so group and steam boiler cycle back and forth)- any measurable loss of performance with relatively light home use? Thanks

You will find as I have - you won't see any performance diff. The pid switches between the 2 boilers ( priority on the brew) within split seconds. I was concerned at first when I heard of this before receiving my machine. I only have 15 amp service. The bottom line-I pull multiple shots in the morning and steam milk. I have never had to wait on the machine in the 15amp mode.

I've had a Duetto II since the Spring and have been running it off a single 15 amp outlet. I have not experienced any power, pressure, or temperature problems with my home use. I brew 4-5 doubles most every morning for my wife and I, and steam 8-12 ounces of milk twice (once for my wife's mocha and once for my somewhere between a cappuccino and latte). I have plenty of steam and brew power, and I usually start the steaming for each of the two drinks while the last double is halfway done brewing. The steaming power/pressure/temperature measured through the gauge and the PID does seem to maintain itself better in 15 amp mode once the brew group is closed. In other words, if I continually brew and steam at the same time, the steam boiler will slowly drop in pressure and temperature (still produce steam, just not as much). Once the brew group is closed, it quickly recovers. This I assume is due to the fact that the computer chip will always give priority to maintaining the brew group temperature. When both boilers are open, you can see the Brew Boiler and Steam Boiler lights rapidly alternating, with the Brew Boiler getting most of the juice. To sum it up, I have plenty of power to steam and brew to my heart's content--even with my in-laws in town and brewing/steaming successively for 8 doubles and 4 8-10 ounce milk drinks every morning, I've experienced no performance problems. I love my machine.

I have mine hooked up to 20 amps and its great. 15 amps works fine but with 20 everything heats up and recovers much much faster.

No issues running in 15 amp mode here. When I have the opportunity to run a dedicated 20 amp circuit, I will, but in the mean time I don't feel like I'm missing anything.

Run mine in 15amp...
I do find that I pay attention after pulling a shot for cappa to the brew temp... if it dropped a bit low from setpoint, I let it recover a few seconds, before starting to steam, otherwise, steam pressure gauge may settle a bit below or right in green region. It's not a big issue, though. I love that they made it support both, one day may try 20amp.

if you have the option to run 20amp go for it. If not then 15 runs fine, but it does take slightly longer to heat up. i am running 15 amps and i experience no noticeable issues.

Works fine on 15 amps for home use even with relatives and brewing 8-10 shots and steaming milk.

The machine is faster than me every time.

Maybe if you are a super fast pro barista you will have to wait.

Not my case.

The machine is great.

One problem. Once your friends and relatives try your coffee they will be returning for more.

Don't say you haven't been warned.

11 amps total in UK. No problem.