I have an older TT that never had a hot water heater. I was thinking of adding - but only want on-demand. (Current on-demand system is filling a pot and putting it on the stove  😛 )

Only need it for washing dishes and maybe (if I add it) external shower option.

Things considered:
LP - Possibly have to replumb LP lines for the whole trailer (rather than tap into old copper).
LP - Pilot Light - wastes gas 90% of the time - rather have DSI.
LP - External vers Internal options. 
LP - Takes up a lot of space (external or internal)

Electric - small on demand solution.
Electric - most are 220v - or high amps 110v (30a or more)
Electric - Most serviced lot are 15a or 30a 110v here.  Very few 50a-220v location.

I am leaning towards Electric (for now). Due to - not having to cut a large hole in the side of the unit. Possible LP if external unit at a later time if boondocking.

Has ANYONE used any of the Marey Heater Corp - like

[img width=495 height=640]http://www.marey.com/product_pics/1.jpg[/img]
http://www.marey.com/productDetailsi.asp?productID=4

Growing up at the cabin (30+ years ago) we had a unit similar to above for hot water for our sink. Was never enough for a shower. It was plugged into a 110v 15a GFCI outlet near the sink. It was great as could turn up the heat an slow the flow - instant hot for tea or coffee. Or faster and have warm water for dishes.

This looks like could use standard threads and plumb it up for the whole trailer.

Cost - maybe about $120

or
[img width=624 height=640]http://www.marey.com/product_pics/26.jpg[/img]
http://www.marey.com/productDetailsi.asp?productID=26

Cost about $200

ANY THOUGHTS or other recommendations?