Abstract: A water heater for exchanging heat between hot gasses and water within the water heater. The water heater includes a water tank, a conduit for allowing flow of the gasses therethrough, the conduit extending through the tank and promoting heat exchange between the gasses and water in the tank, and a baffle extending within the conduit for affecting the flow of the gasses. The baffle includes a sheet bent in a zig-zag manner and having a number of plate sections. Each plate section has a through-flow portion allowing the gasses to flow therethrough. The sheet also has a number of first bends and a number of second bends, the first bends alternating with the second bends such that each plate section is defined between one first bend and one second bend.