Make a Fireplace Water Heater

By Lyman D. Schwartz
Published on November 1, 1978
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PHOTO: LYMAN D. SCHWARTZ
The grate is actually a fireplace water heater—a network of pipes through which circulating water picks up heat and carries it to other parts of the Schwartz home and TV shop.

My fireplace saves me money four ways: (1) It keeps my living room and kitchen warm, (2) it provides “hot water” baseboard heat for my TV shop, and (3) it preheats water for my electric water heater, which (4) thereby provides my family with a far greater supply of hot water to use … without costing us a penny extra!

We pretty much run our fireplace day and night during the winter. With heating costs as high as they are today, I hated to see all that warmth going up the chimney. So I set out to do something about using some of the “wasted” heat.

The solution that I came up with is inexpensive, fairly simple to put together, and darned effective, too! I built a fireplace water heater. It’s a grate made of 1″ (internal diameter) black pipe through which I run water from a 75-gallon storage tank, right under the glowing coals. The system uses an electric circulator, which operates continuously while the fireplace is in use. I also installed a backup circulator, powered by a standard 12-volt auto battery, that kicks in automatically if the electricity goes off—as it frequently does during our Gettysburg, Pennsylvania winters.

This setup gives me approximately 80 gallons of hot water, which I feed through another circulator into 55 feet of baseboard heater in my hard-to-warm, north-facing, 20′ x 34′ TV shop … and into another 10 feet of baseboard that runs along our home’s central hallway.

The kitchen and living room get their heat from the well-insulated, blower equipped, “Heatilator” fireplace itself, and the bedroom stays at a comfortable-for-sleeping 58° to 80°F with no heat other than the overflow from the other rooms. To keep the house cozy all night long, I fill up the fireplace once before I go to bed, and again between 2:30 and 3:00 a.m. My standard hot-air furnace will, of course, come on if things get too chilly in the wee hours, but the house hardly ever gets cold enough to make that extra (more expensive) heat necessary.

I also installed a thermocouple and a pyrometer heat meter in my system, so I’d be able to check the temperature of my “stored” water at any time. The meter is capable of reading up to 250°F, and my storage tank’s water averages around 130 degrees. (I’ve actually gotten it as high as 195 degrees on several occasions, but that requires one heck of a hot fire!)

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