hello all new to this site and looking for some educated advise. I am currently heating my home with an Earth outdoor water furnace. After heating with it for a few years my wife and I are wanting to also start heating our domestic hot water with the furnace as well. I will have to install a heat exchanger at the electric water heater to accomplish this as the OWB does not have a coil in it for domestic water. There seems to be two options a brazed plate in series with the current water heater's supply or a sidearm exchanger that mounts to the drain and relief valve of water heater. It seems like the sidearm would keep the water heater from needing to run while we were at work and not using water, whereas the flat plate would only heat the water when the hot water was being used and the tank was refilling. Could the brazed plate heat exchanger be used in an "on demand" fashion, where I could plumb it so that I could bypass my water heater when I am heating the house with the OWB? Or would a sidearm heater work better to eliminate the need for an electric hot water heater all together? Also, will either of these heat exchangers work efficiently if I plumb them in series and downstream of the water to air exchanger for the furnace? Will heating my domestic water in any of these fashions drastically increase my wood consumption? Sorry for being so wordy and thanks for any help.