Note that I reviewed several water heaters before buying this one. This one does an adequate job heating one shower at a time but don't run water elsewhere or your shower will go cold. I turned the unit to the hottest setting (140 degrees) and the shower has a nice hot flow, but does sometimes go cold. I would definitely look for one with more GPM and also poassibly a 3/4" inlet and outlet insteaf of just 1/2". As for the venting, buy the specific venting for the Eccotemp at about $175. online which was not bad.