I have tried leaving my water supplies in the sun all day, and even on hot days, that's not adequate. Sure, the water isn't cold cold by the end of the day, and it's OK for washing hands, but to my way of thinking, it never gets warm enough to take a warm, comfortable shower--a cold shower, yes, but not that's not comfortable.
So my latest glamping equipment is a BoundaryTec shower coil. http://www.boundarytec.com/1530-showerc ... shower.php I ordered the full enchilada, which includes the shower coil, 2 water bags (15 liters each), and the connecting tubing. First, the delivery was very fast. I ordered it last winter, and it came within a week. Second, it was exactly as described in their website, and appears to be well made of quality materials. On a cool but dry day, I tried it out in our driveway. I used my old but supremely efficient MSR XGK backpacking stove--the newer ones are probably more convenient, but the heating specs are the same, so I'd highly recommend one as a heating source. At first, I was disappointed in the temperature of the water, so I turned up the thermostat. But I didn't test it again.
The first time I was able to use it "for real" was at the Meredith Lake seaplane splash-in, a couple of weeks ago. I heated the water per their instructions, and this time it was nice and warm! That took about 15 minutes. I then drained the water from the heated bag into my Nemo Helio shower system, which provides water pressure for showering without the need to hang the shower bag--it's conveniently the same volume as the BoundaryTec bags. I have a shower tent for privacy (nobody wants to look at my ancient bod, anyway), and I erected it and staked it down while waiting for the water to heat and drain into the Nemo Helio. And it works gloriously well! I had a very nice, warm shower, using about half the water in the Nemo Helio.
When camping, I can go a couple of days without a shower, but pretty soon I feel pretty grubby. Having a comfortable shower in camp makes a huge difference in my own comfort (and perhaps makes me more acceptable to those downwind from me). I highly recommend the BoundaryTec shower coil for anyone who wants to have a warm shower in the back country.
Cary

