Yes, we are here!

At MOTHER EARTH NEWS, we have been educating folks about the benefits of self-reliance for 50 years. That includes researching and sourcing the best books and products to help individuals master the skills they need in times like these and beyond. Our online store is open and we are here to answer any questions you might have. Our customer service staff is available Monday through Friday from 8a.m.-5p.m. CDT. We can be reached at 1-800-234-3368 or by email. Stay safe!

Dual-Mode Hot-Water System Heated with Solar and Wood

| 11/10/2016 10:07:00 AM

How the Dual-Mode Solar-and-Wood Water Heater Works

Having hot water for showers and dish washing is certainly a joy that makes off-grid feel as luxurious as on-grid, yet without utility bills or fossil fuels. Where I live, summer sunshine is abundant, but winter cold requires the heat of a woodstove.

In summer, I connect to the solar hot water panel in the greenhouse, and in winter to the hot water coil on the wood stove pipe. I have cold and hot water tanks, located upstairs, to provide gravity-fed hot and cold water to a kitchen sink and a shower on the lower floors. The hot water tank is filled manually, by a pipe and valve plumbed from the cold tank.

I let the hot water tank heat all the water in the tank to a usable temperature and then use it. Hot water is circulated to the hot water tank by heat convection — no pumps.


The solar collector heats my ten gallon hot water tank to 120 degrees Fahrenheit in about three hours on a summer day, even if partly cloudy — the stove pipe coil heats the tank above 130 degrees F in about two hours, or three hours if the starting temperature of the tank is near ice-cold.

A surprising discovery is that the hot water coil will lower the stove pipe temperature by 100 degrees F when water is circulating. Depending on how hot the water in the tank is, and if I mix cold at the faucet, showers use 2-1/2 gallons and washing dishes use 2 to 4 gallons per day. The tank will drop about 20 degrees F overnight or after the woodstove has stopped burning.

Solar Hot Water Collector

The solar hot water collector panel is made with an array of CPVC pipe on a flat plate collector (3 feet by 5 feet). It has ten 1/2-inch collector tubes that “T” into a top and bottom manifold that is 1 inch CPVC and routes to the hot water tank. CPVC pipe can withstand 200 degrees F, while the hottest temperature on my flat-plate collector is 130 degrees Fahrenheit.

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

click me