I moved into a new apartment with a «tankless» hot water heater. It was taking way too long to get hot water in the bathroom sinks. Apt management was dragging its heals. Jim Butcher, owner of Blue Conservation LLC(a plumber specializing in these types of heaters) gave me some very valuable free advice and info on the phone, which I was able to use to convince the apt management that something should be done about the problem, and to have Jim do it. This involved recirculating pumps under each bathroom sink, triggered by an infrared sensor at the bathroom door entrance. This unique solution was proposed by Jim. I highly recommend Jim, who is an expert in tankless hot water heaters, and is very nice to boot.