One of the big decisions we had to make when we were planning our new off grid home was what kind of heat we were going to have? We pretty much eliminated anything that would require electricity such as a heat pump or forced air furnace since we’re going to produce our own electricity with solar power. Ideally an underground home with passive solar design was the very best design concerning heating but Laurie may have put me underground about 6’ if I tried to put her in an underground house so we had to keep looking.
We considered geothermal but it wasn’t practical due to water availability concerns and again, the electricity required for the pump. We were trying to stay away from propane heat in the pursuit of sustainability.
We did have 40 acres of trees and wood heat was a consideration but what would be the best kind of apparatus to deliver the heat? I had heated for years with a wood stove and didn’t particularly like the unevenness of the heat circle. If you place them where you live (living room) it can get pretty hot up close. A wood furnace would once again have the need of electricity for the fan to circulate. Fireplaces are not efficient or effective with the possible exception of a Rumford.
At the time we were planning this new home I was fortunate enough to be self employed in the commercial masonry business. I was discussing the heating issue with a colleague one day and he asked me if I had considered a masonry heater for my primary heat source. Well, I just told you I was the Owner but I never said I was a professional mason. He explained to me that there were other terms like Russian stove or Russian fireplace etc. I had heard of those before but didn’t know what they were. I started doing research as soon as he left my office.
The short of it is that we did indeed end up with a masonry heater as our primary heat source. We also had a wood burning kitchen stove and oven built on one end of the heater. I can’t tell you how happy we are with our choice. These heaters are over 95% efficient. Some claim they are the cleanest heat source available in terms of emissions. They burn so hot that all of the gases and toxins are burnt up before they go out the chimney. Once the fire is started they are virtually smokeless.
They work differently than a woodstove. When a woodstove gets too hot you have to damper it down and they don’t always burn as clean as you would like when that happens. You also have to keep a woodstove going 24/7 in the cold months.
Masonry heaters are different. They are a solid mass of brick and/or stone with a unique course for the exhaust to travel from the firebox to the chimney. The exhaust chamber starts at the firebox and then winds through the mass of masonry before it exits out the chimney. This allows the masonry mass to be heated thoroughly in a short time. We burn our hot fire for about two hours and then shut it down completely. Fire out. The heated masonry mass then continues to emit passive heat for the next 10 hours. Passive heat is the most comfortable heat there is. It is the same type of heat the sun puts out. You can even touch the outer stone with your hand without getting burnt so they are much safer for children and pets to be around.
Because you only burn for two hours twice a day you save on wood. We are going to use about six cords of wood per year but we live in cold country. This heater has kept our house (1400 sf) at a comfortable temperature when it was down to -9 degrees F so far. We did have to close off two rooms that didn’t need to be heated. If we need more heat or if we don’t want to close those two doors we just light a fire in the kitchen stove. If I had this same heater in my old house I would only use about three cords per year. We have even learned to use our kitchen stove to heat the house in the milder temperatures like spring and fall. That takes about an armload of wood per day.
These heaters have been around for hundreds of years. They were developed and are still quite popular in Europe. Mark Twain commented that they were the most comfortable heat he had ever experienced after a trip overseas. They were developed as Europe became more populated and wood became scarce. Short hot fires to heat the mass and then let the mass emit heat for hours afterward. Most of them had ovens and even platforms for sleeping attached.
There are six different types of masonry heaters. Ours is a Finnish Contraflow. Each type has unlimited design ability. They are all custom designed and built.
There is a downside to these heaters. They are expensive. I may not have had ours put in except I was in the business and was able to cut the costs considerably. You can’t imagine why they cost so much until you see one being built. They are complicated to build and require more material than you could ever imagine if you didn’t see it with your own eyes. There is a legitimate reason they are so expensive. I should also mention that you have to burn relatively small pieces of wood, not to exceed 4”. That means way more splitting than a wood stove or furnace.
You can build one yourself but I would caution you to do a lot of research on the design and size before you do. If you are going to hire it done like I did, make sure your designer/mason is qualified and experienced. This is too large of expenditure and too important to your well being and comfort to do otherwise. For references or research I would suggest you start at your local masonry supply store or visit the MasonryHeater Association Of North America on line. You might also look at FirecrestFireplaces .
As an aside, we did put direct vent propane wall heaters in as backup if we have to leave the house for any length of time during the winter.