Merry Christmas to Dave & all: Tankless water heaters range in size from 3kw to 28kw electric, and 38,000-165,000btu. We can output 3.5 to 4.5gpm at 120 degrees indefinitely, or higher temperatures at lower flows. We have units small enough to fit under the sink, or big enough to fill a Jacuzzi or run a commercial laundry. If you need more info, please call me at 800 851 9891 or e-mail me at firstname.lastname@example.org . I hope I have helped put your fears to rest. Sincerely, Brian Wood.