Hi my name is Ken. I have been retired for about 5 years now and just bought a 8 unit apartment building,the last owner had the gas co. install 4 units of hot water on demand units and said it will cut down on your gas bill.Well the only thing it seams to be doing is the gas bill is about the same but my water bill much higher as it takes about 5 minutes for the hot water to get to each apt. I was wondering if I would be better of with Two hot water tanks with a circulating pump, and insulate the hot water circulating line. Any help would be greatly appreciated. Ken

what uses less energy, zone valves or circulators? 12 zone circulators or 12 zone valves with a differential bypass valve? do zone valves only take energy when switching to open or closed but take no energy when standing? also are there zone valves on the market that do not consume energy after switching?