Julie is right. Worthington (distributors) has an awesome forum on HAI. As for the phase coupler, it is recommended but we have found good success without it. As long as you can pass a signal, and have neutrals in the switch gangs, you are generally cool. No IR for the dimmers and they have not yet released a 1000 watt dimmer. It's good to be involved in the design stage of the house. Often, the sparky will pull the neutral to the load and a hot leg off that for the switch. This is no good. HAI is great stuff but don't buy it when their salespeople promise the moon. They will claim that there is no special wiring requirements to run UPB but, that is not grounded (I couldn't resist) in the real world.