I’ve been thinking about the best way to heat water for the tiny house this week, and have finally decided to go with gas. I had considered solar, which is in keeping with the green theme and off-grid nature of the house, but it would involve a lot of extra equipment and expense. To start with I’d need a water tank to store hot water in, and that takes up a fair amount of space, the panel would be large and, unless I built my own, quite expensive. I did think of building my own, that was my original way into green technology when I was about 14 and built solar water heaters that could provide hot water for washing up etc. But in such a small house it’s not really practical.
I then looked at a back boiler for the little woodburner I’ll be fitting for winter heating but again you need storage and additional plumbing. So I’m going to go with an instant gas water heater, which will be simple to install, cheap and efficient. Ideally I’d like one of the Bosch ones designed for off grid homes but you can’t buy them in this country and that makes it expensive to install.
Interestingly, there seems to be some confusion amongs manufacturers as to what you would need in a mobile environment and how to provide a suitable device. Ideally, you want a room sealed heater, ie one that takes it’s combustion air from outside and pipes it’s exhaust outside too. In fact, if you’re selling a device for motor homes, caravans etc, this is a requirement. It’s strange then, that the only one of these I can find requires mains electricity to run the igniter, whereas the heaters that aren’t room sealed (ie are for things like static caravans etc) are generally powered by a couple of batteries. Surely it should be the other way round.
In the end, I’ve decided that I’m going to go for a heater that isn’t room sealed, mainly because it will run for such a short time that there’s not going to need to be much air supply drawn from inside the house. It will only be one when I’m running hot water from the kitchen tap for washing up or when I’m in the shower, which won’t be for that long as I’ll be aiming to conserve water as much as I can. The heater I’ve found that looks a good buy is available direct from China on ebay
and details can found here
I’ve been working on designs for two water systems and the rainwater capture which I’ll post next time. Undecided on which one to go for right now, so more pondering to do.