We're doing a remodel of an old house (1914) and I was told by my brother (a plumber) to go with an indirect hot water heater. The boiler will be a direct vent boiler and I'd like to get your opinion on them (indirect HW heaters)as opposed to the gas fired hot water heater (40 gal) that she now uses. We'd need to be upgrading to a bigger hot water heater in any case because I'll be moving in with her. Any help would be appreciated.