Yes the heat escapes very easily! Ivwany one if the gas water heaters but the water pressure isn't enough here, so I would need some kind of pump...am thinking black pipe coiled under perspex (not glass as my van drives ;-). Or the copper pipe around stove pipe, but that's not great when weather warmer!. Great you got a friend with horses, did you see that documentary 'the path of the horse' nice variety of natural training methods in there. I had to sell my horses as with new baby I couldn't do the 3x day feeding needed here in south Spain, its high maintenances here, no green fields, miss them lots. later will do another trek and for much longer,, enjoy your time with the horses and I'm sure one will find you :-)