Well we installed the rinnia model 2520 at the office and now there is little to no hot water. It takes 5 minutes, the plumber guy says well it comes out at 120 degrees but by time it gets where its going it drops to like 90 degrees. Still feels cold to us. He claims its because the pipes are in the ground which does makes sense. We are discussing having the pipes rerouted, and he is suggesting most of the walls would have to be torn down. Does this sound about right? The whole scenario, not just the wall thing. We had better overall response with a hot water heater....btw...Thanks for any info