On my land I have a copious supply of wood and heat the house with it. My water heating system, however, is electric. I would prefer to be heating my water with wood as well since, for me, it is free. Does anybody have experience with wood fuelled water heating in their house?
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Yes David - we have a big woodburner that heats the water and drives 12 radiators! We have a big old farmhouse.
The system needs careful design. We have a large tank that has an electric element plus 3 additional coils - one for the woodburner, one for solar panels, and one to put a boiler back into the system if required.
If you have your own wood and fit solar too you should get free hot water pretty much all year. Like you I have enough trees for this, but it is a lot of work, and if I’m not able to do it we have to buy about 5 cords of wood, costing about 1,000€, over a winter.
It is possible I think to put the central heating through the tank coil, but our system has separate circulation through the woodburner for the heating and water. The big issue is the lack of control of the water heating - you must have the recommended size of ‘heat sink’ radiator on the water circuit, and this must be pretty directly above the woodburner so that the system will not overheat the water even if there is no power to the pump. You will need somebody who knows what they’re doing to design and fit it, and they will advise on all these issues - but I can tell you it works well!
Our house is heated with a solarbayer evs wood gasification boiler which then heats a 2000litre tank to feed the under floor heating. We burn once a day throughout the Winter months and every couple of days in Spring if it’s cloudy (it’s also connected to our solar roof coils) it’s simple to use and works well to keep us Comfortable.
You can go from something as simple as a log burning stove with a water jacket that heats a radiator circuit, to a log burning cuisiniere that is one of multiple fuel sources heating a heat store (or buffer) of 1000-5000L. In the latter case you can add anything else, e.g. solar thermal panels, electric immersion heaters, gas or oil fired burners, geothermal exchangers, etc.