The problem is when impedance drops in half, current flow doubles. If the 1400 is producing 1400 Watts of output at 4 Ohms, it'll be 2800 at 2, 5600 at 1, and 11200 at 1/2. There's no way any part of the amp could stand up to those levels.
I don't know why you'd select such an amp for whole home audio, it really isn't suited to the task, unless you're running M80s in every location.
Whole home audio is at odds with fidelity from the start. But if that is the goal, I'd get a pre-amp with balanced outputs, split them with gear designed for the job (not just Y-cables), and do the runs with good quality balanced cables. Then stick amps in each room with speakers, and turn them on and off where I wanted sound or not.
Or get a distribution amp designed for the task (like the ATI AT 6012
http://www.ati-amp.com/at6012.html ), and use individual speaker on/off switches, not the multiple selector.
