I highly recommend this type of setup. I installed fin tube baseboard radiators throughout my house instead of messing with a heat exchanger in my forced air system. It uses 1 zone valve and a thermostat. When the house calls for heat the valve opens and it runs through the side arm for the water heater and then through the house loop. When the valve is closed it only runs through the side arm and then back out to the OWB. My forced air furnace is on the main floor and serves as a backup, but I sure don't miss listening to it run. I'm sure I save some on electric as well. As to baseboard wanting 180* or better I don't know, but I've never had a problem keeping the house at 72* even in sub zero windy weather with my set points at 175 and 185.