InSinkErator H-HOT150SN-SS Invite Single Handle Instant Hot Water Dispenser, Satin Nickel

Q: Does it come with a power cord?

The one I ordered recently came with power cord.

Q: What is the difference between this model and h-wave sn-ss model?

This model is more economical "Invite" series, and h-wave sn-ss is more expensive "Involve" series. And the faucets are different. I regret I am not much help, but I just spent 10 minutes on Amazon site trying to figure out the difference. The more expensive model reads just like my more economical model: it makes 60 cups of hot water. Not sure what you get for the extra $110.

Q: How much room is needed behind the spout in order to turn the handle a full quarter-turn? Or, put another way, how far does the handle protrude?

You need 2 inches from the center of the hole for the handle to rotate to the rear 1/4 turn. I'd want 2.25 or more inches.

Q: Do you have to turn and hold the handle constantly in order to get hot water or can you turn and let go?

This is a safety feature; user must turn and hold handle for hot water to dispense. An unlimited flow of near boiling water could cause burns quickly.