I work for a hardware/plumbing store (Score 1)

I work for a hardware/plumbing store, and we sell tankless water heaters. They do have the ability to heat up water in-line, but the difference between this and others is, at least with the ones that we have access to, ours can only serve the purpose of heating for a single application at a time. You can put one under the sink to heat that one line, or you can put it by the shower to only heat the shower, while these will be able to furnish heated water to multiple locations simultaneously. So that is a pretty nice advantage.