Gas water heaters rely on natural gas or propane to ... How long does it take to install a 40-gallon hot water heater? The installation of a 40-gallon hot water heater typically takes two to ...

Both tanked and tankless gas heaters send hot exhaust gases out of the flue ... "The cost and efficiency differences between a 40-gallon and a 50-gallon water heater are usually minimal," he says, "So ...