Use Your Wood Stove as a Water Heater

Your wood stove can heat more than your home. This hot water heating system uses extra heat to produce hot water that will stay warm up to 48 hours!

  • 042-061-01a
    Figures 3 and 4, showing placement for your water storage tank.
  • water heater
    Your wood stove can provide piping hot water for a relaxing shower.
  • 042-060-01a-01
    Figures 1 and 2, showing conventional water heater design compared to the Blazing Shower System
  • 042-061-01tab
    Types of wood stoves for use with Blazing Shower systems.

  • 042-061-01a
  • water heater
  • 042-060-01a-01
  • 042-061-01tab

Three years ago, we were sitting in our cabins wondering how we could satisfy our addictions for hot baths and showers, without paying ridiculous prices for disappearing reserves of fossil fuels. Putting our talents together (one of us is a mechanical wizard and the other a Ph.D. chemist), we devised a homestead alternate energy system — based on the use of otherwise-wasted stovepipe heat — that's allowed us to take those hot baths. We call our system the Blazing Showers Stovepipe Hot Water Heater.

Hot Water Basics

As you can see in Fig. 1 (see Image Gallery), an ordinary water heater is nothing more than a storage tank (located between a house's water source and its various hot water faucets) sitting over a gas or electric burner. Since water tends to rise as it's heated, cold water is piped in at the bottom of the tank, while hot water is drawn off from the top.

Fig. 2 compares such a conventional water heater with a Blazing Showers system. As you can see, our setup employs a coil of copper tubing — located inside a wood burning stove's stovepipe — to heat the water that's held in our storage tank. Hot smoke rising through the stovepipe warms the water in the copper coil, which causes it to rise (and thereby draw more cold water into the coil). Meanwhile, the stovepipe-heated water flows into the top of the storage tank, where it remains until someone decides to take a "blazing shower" and turns on a faucet.

Notice that there are no pumps in our system: Instead, plain ole thermal convection does all the work.

Hot Water... Overnight!

How long does it take to fill a tank with hot water this way? The answer depends on how cold the incoming cold water is, how many gallons your water heater holds, and how hot the flame is in your stove. We estimate that a blazing fire in an average-sized wood-burner can produce 20 gallons of hot water per hour. And—if you store that heated water in an insulated tank as we prescribe—it'll remain hot for up to 48 hours after the fire goes out. What this means in practical terms is that if you have a fire in your stove one evening, you'll still have all the hot water you want (for bathing, dishwashing, etc.) the following morning when you wake up. In fact, that water will actually remain warm for two full days ... even if you don't light the stove again at any time during that period.

First Things First: Storage Tank

The first thing you need before you can install a system of your own, of course, is a storage tank. If you already have a hot water heater, you can use it ... otherwise, look around for a "previously owned" unit.

7/28/2019 7:16:15 AM

The article mentions "the storage tank adapter" in "figure 5", but it is absent. How may figure 5 and the details for the storage tank adapter be obtained? Thank you.

5/14/2019 6:07:46 AM

Hi, I live in France and they only sell cheap storage tanks here with one inlet and one outlet. So that's it! In the US you have an extra hole on the top for a valve and you can use the drain to connect to your woodstove. So my question is. If I would install my water inlet with a T junction where you have the water go into the woodstove, would my circulation be fine when I open my hot water for a shower? Will The water always take the way where it meets the least resistance? So it would fill up the bottom of the tank and not go through my coil around my woodstove? Thanks.

2/5/2018 9:02:37 AM

Interesting article. The use of a wood-burning stove as a water heater can be a good alternative to an electric or gas water heater. But for installation of such a water heater, it is necessary to observe the installation and exploitation rules. The use of wood as an energy can be cheaper than using gas, electricity or another source of energy. But there are a number of shortcomings that should be considered if you decide to install such a water heater or use the stove as a water heater. 1. It is necessary to select the correct fuel. When choosing fuel, it is necessary to understand well the heat capacity of the material. 2. The water heater, namely its furnace, needs regular cleaning from the ash and residues of combustion, at least once every two days, and preferably daily. 3. Doors of the furnace and other compartments must be regularly greased with graphite grease to ensure a tight fit, otherwise, the smoke will enter the room. Therefore, if you decide to install such a water heater it is better to seek help from a special company. A list of such companies can be found on the website - Installation and operation of such systems is a very complex and time-consuming process. Therefore, it is better to seek the help of professional engineers.

Subscribe Today - Pay Now & Save 64% Off the Cover Price

50 Years of Money-Saving Tips!

Mother Earth NewsAt MOTHER EARTH NEWS for 50 years and counting, we are dedicated to conserving our planet's natural resources while helping you conserve your financial resources. You'll find tips for slashing heating bills, growing fresh, natural produce at home, and more. That's why we want you to save money and trees by subscribing through our earth-friendly automatic renewal savings plan. By paying with a credit card, you save an additional $5 and get 6 issues of MOTHER EARTH NEWS for only $12.95 (USA only).

You may also use the Bill Me option and pay $17.95 for 6 issues.

Canadian Subscribers - Click Here
International Subscribers - Click Here
Canadian subscriptions: 1 year (includes postage & GST).

Facebook Pinterest Instagram YouTube Twitter flipboard

Free Product Information Classifieds Newsletters