… the guys at Great Water in Maine gave me a great price, and were extremely helpful with install advice. I was in Florida at the time, I paid for it and was able to go to the factory in Florida and pick it up. This replaced a then 20 year old Raritan 12 gal that lasted that long just fine. I really do like the Isotherm/IsoTemp, have been very happy. We are three onboard, we usually shower every day in the Bahamas, I have never run out of hot water. We move around a lot, plus in addition to a 12V system, I also have Sea Frost engine drive refrigeration, so we run the engine for 40 minutes every other day, if we are not moving. I have found the Isotherm is better insulted than the Raritan, but that Raritan was 20 years old, and had fiberglass insulation. We can easily go well over 24 hours and still have HOT water, more like 48 hours (in the Tropics) and still a nice, comfortable shower. I know how many folks don't care for hot water showers in the Tropics, but we like them, thank you. My install was rather tricky, we wound up making a custom bracket for the water heater, I bolted this to the underside of the winch bolts under the port coaming, so the water heater tucks up nicely and hangs from this bracket underneath the port coaming, so it's not in the way of anything. BUT, I'm not sure I like that weight out there, it does make a difference. I haven't seen weight mentioned here so far … that extra 6 gallons of water is going to cost you 50 pounds. Perhaps not a big deal, but 50 pounds here, 50 pounds there, next thing you know the waterline gets a little closer to … the water ! Our boat is small (by today's standards) at 40 feet. I'm getting to the point where we are trying to take things, and weight, off the boat as opposed to putting things on. Feng shui. Every new install I contemplate is greatly influenced by weight these days, whereas 10 years ago it never occurred to me. I will easily spend more money if it means whatever it is I'm doing will weigh less. I went thru the same decision you are going thru back then. If I was to do it again today, I would either (A) go the route Max has done with the Precision Temp Propane, or (B) probably go with Isotherm's 24 liter (6.4 gal), because of weight & size … and now we are two, with the hot-water hogging teenager rarely onboard these days. The reason I decided against the Precision Temp back then was because we are constantly moving, rarely are we in one spot more than a couple days, so I considered that free heat, and we only have space for one 10# propane tank and getting that filled in the Bahamas isn't exactly convenient.

One thing to think about, assuming you will have this unit heat water by the engine as well as 120V, is that the Isotherm unit has the expansion relief valve. I connected a hose to that and drained that to the bilge. When the engine runs for any length of time, the Isotherm will drip (hot) water constantly, not much, but some that you will need to prepare for and deal with.

We have a cockpit shower and a Head Shower. Never use the Head shower, always the cockpit shower, both have an on/off on-demand wand. We are conservative, our showers are short.

Cheers, John