Green Remodel Forum

Don't use recirculation pump with tankless water heater, or your warranty maybe void.

sounds like you may need a water hammer, or check to see if there is an in line valve somewhere that is not completely open. A plumber can install a hammer but you can check the valves.

Tank-less is more expensive. Install tank hot water is easier. All you have to do is to
replacement another tank hot water and nothing else. To install tank less you need a different flue and bigger gas line, more work, more money.

Storage hot water tank can last for a long time if you maintenance it every year. See Water Heater Rescue website.
http://www.waterheaterrescue.com/pages/ ... nance.html