A wood-fired hot tub

The view from an upstairs window.

My hot tub is a non-electric setup that combines a $60 stock tank and an external Chofu woodstove.

The lid is a scrap of blue styrofoam insulation.

The stock tank has two connections to the wood stove: one pipe near the bottom of the tank, and another about 8 inches from the top. As I fill the tank (using a hose from the garden), water travels through these pipes to fill the water jacket that surrounds the fire box.

Once the tub is full, I light a fire in the stove. As the water in the jacket warms, it rises into the tub through the top pipe, which pulls cold water from the bottom of the tub through the bottom pipe. So with no pump, the water slowly circulates and heats itself.

It takes about an hour and a half to heat the tub. Depending on what I'm burning, I check the fire every 20 to 30 minutes. If I'm really lazy, I use one of those tacky sawdust logs and let it do all the work.

Once everything is hot, I shut the stove door, stir the water with a scrap piece of plywood, and hop in. While I soak, coals in the firebox keep heating the water. If it gets too hot, I squirt in cold water from the garden hose for some classy jet action.

Back in the garden, there's a chlorine filter on the hose. So the tub has less chlorine than a conventional bath, and I don't keep the water in it for more than a couple of days.

I plan to insulate the tub some day, so it will take even less wood to heat it.

Links

I got the Chofu from Backwoods Solar. It can burn wood or coal.

Chlorine filter for the hose