Masonry heaters: Expensive, but worth it.

These people have a relatively modest home, but their heating system is fit for a palace!

COUNTRYSIDE'S report on the 1998 Midwest Renewable Energy Fair included a discussion on masonry heaters. We have a custom-built masonry heater in our home and like it very much.

I turned 55 two years ago and took early retirement from my job in another part of the state. My wife, a teacher, left her job as well, and we moved to north central Minnesota, where we are building a homestead on 40 acres of woods and meadows. We cut our own wood, garden, raise a couple of pigs, and keep a small flock of hens. Even though we are building our homestead somewhat later in life than most, we look forward to many satisfying years beyond the sidewalks.

We sold our house in our previous location and used the money to build a small, two-bedroom energy-efficient home. We have about 1,100 square feet of living space, plus a full basement. The home has an open floor plan, and the masonry heater is its central feature. The heater, a modified Finnish "contraflow" design, sits in the middle of our 14' x 28' kitchen, a small mudroom and a hallway leading to the bathroom and bedrooms. The radiant heat from the masonry heater keeps the house cozy all winter, and we don't have to use the electric back-up heat even on the coldest days. An open floor plan maximizes the efficiency of the heater.

Normally I fire the heater twice each day, usually between 6-7 in the morning and 6-7 in the evening. I put about 12-15 pieces of firewood in the box, add some kindling, open the outside air intake and the damper, light the fire and close the see-through glass and iron doors. With the aid of outside air coming in the firebox, the fire burns very hot, complete and clean, and there is virtually no creosote buildup in the chimney. Masonry heaters are environmentally sound because as COUNTRYSIDE'S article noted, the high temperature combustion results in few emissions.

The hot wood gases first rise up through an opening at the top of the firebox, pass through a bake oven on the back side, then head downward through two channels on either side of the firebox. When they reach the bottom of the heater, the gases are channeled through the chimney at the side of the heater.

During this process, most of the heat is absorbed by the mass of firebrick inside the heater. The heat then radiates out from the heater. Because the doors are kept closed, there is no smoke or smell to contend with. With heat evenly radiating from the heater throughout the day, there is little change in room temperature between firings, and there also is a minimal difference in air temperature at the ceiling and at the floor. We couldn't say that with the forced air heating system we had in our other house.

On mild, sunny winter days, we may fire the heater only once. Our house sits on a small hill, with a southeast exposure, and we put in lots of windows with low-E glass on the south and east sides. Thus we are able to take advantage of the sun's energy on nice days. The low-E glass lets in the sun's radiant heat in the winter, while reflecting away those same rays in the summer. In the spring and fall, we sometimes build smaller fires in the heater just to take the chill out of the house.

The past two winters have been quite mild by Minnesota standards. We burned a little over three cords of wood the first winter and a bit less this past winter. Even so, if next winter is much colder, I don't expect to burn more than four cords, since it is not efficient to fire the heater more than twice a day. Whether the outside temperature is 20 degrees above or 20 below, two fires are enough to keep the house warm.

Ash removal is easy. There is a hole at the bottom of the firebox, and I simply remove the cover and push the ashes into the hole. The ashes drop into an ash pit in the basement (the heater sits on a concrete block foundation built up from the basement floor). Because of the complete burn,;, there is a relatively modest amount of ashes. I hauled out only six five-gallon buckets of ashes following the first heating season and about the same amount this spring.

The bake oven is a very nice option, and we use it to bake bread, rolls, stews and the like. Once the fire is out, the bake oven is ready to use, and the mass of heated brick around it keeps the oven hot for a long time.

The bench at the front of the heater is another nice option. It's great to come in from the cold and sit on the warm, granite-top bench for a while.

We discovered an additional benefit in having a masonry heater. Because the basement doesn't contain a furnace or a network of heating ducts, it stays quite cool during the heating season. We store potatoes, carrots and squash down there, and this year we are walling off a small area in one corner to serve as a root cellar.

Although several companies offer prefabricated kits for the internal flue system, with local masons adding the outside brick or stone, we chose to have our heater custom-built, inside and out, by Richard Larson, a talented mason who lives in our area. He has a masonry heater in his home as well. He used remnant pieces of three-and four-inch thick Minnesota granite for the top of the heater, the mantle and the benchtop. We chose brick for the exterior. The heater is a beautiful thing to behold and a beautiful thing to experience.

The heater cost us $6,900. The high cost is a major disadvantage, for sure, but my wife and I feel the investment is worth it. The heater will last for many years. No electricity is required to operate it. I would rather have a small house with a masonry heater than a large house without one.

In addition to their initial cost, masonry heaters have other disadvantages. You just can't go out and buy one, like a wood stove or gas furnace. A lot of planning is involved before construction can begin. Also, you need a back-up heating system to keep the house warm when you are away for more than a few days. We spent an additional $900 to install electric baseboard heaters as our back-up. In addition, you can't get instant heat from a masonry heater. It takes a while to heat up the mass of brick and stone.

Homesteaders interested in this type of heating system should write the Masonry Heating Association of America, 11490 Commerce Park Dr., Reston, VA 22091 or call [phone] for more information. The association also maintains a web page with lots of information and photos.

BILL TURGEON
RR 2 Box 159A
AKELEY, MN 56433