The problem with tankless systems is the huge power required on demand. Which, with the necessary heavy wiring and switching also adds up to lots of dollars. I have a traditional longhouse, [aptly named- it's about 144 feet long!]. With bathrooms at either end, now that the old stables, hay barn and machinery shed now have us both esconced in them, a single hot water supply would have been problematic, to say the least. I fitted 200 litre [52 USG] chauff eaux, [hot water tanks] running at mains water pressure of 45 psig near each bathroom and tapped off to the kitchens. [Yes, we got 2 of those as well, due to the remodel]. Power is only 2kw per unit, [230V @ 9A], run on cheap night and 2 hours midday tarif, which you can over-ride if required. These can be got for c. US$ 450 or less here, sizes up to 300 litres/ single unit. The heating is oil fired hydronic, which is not used for our domestic hot water. We use an average of 110 liters [26 gallons] of potable water a day, discounting the toilets, which are flushed with pumped well-water, biologically clean but makes lousy tea!
My units are foam insulated and stay hot for days if turned off, which one of them usually is unless the ankle-biters turn up for a free vacation. They are marketing solar-aided chauf eaux here now. When I looked at the price tag, the only thing that got hot was under my collar!
