Axiom Home Page Forums General Discussion The Water Cooler Masonry Heater is up and running

Hey John!
I have a question also:

If you DO want a fire for aesthetic reasons, is there a way to "bypass" transferring so much of the heat to the masonry via a fan or different duct? Or, would you have to walk around in your boxers for three days because the place is too hot?

>>Ok, so the brick and mortar mass stores the heat for up to two days. Does that mean you really only need to fire up the stove with one good fire per day to get/keep the house warm?

Yep, that is one of the biggest attractions of masonry heaters, especially the fact that you don't need to get up in the middle of the night to feed the fire. Your "one fire a day" obviously has to be fairly big, maybe 50 pounds of wood, but you still end up burning less wood than a typical woodstove would consume given the same heating task.

When it's bitterly cold I expect it may take two fires a day, one in the morning and one in the evening, although the house is pretty well insulated so one might be enough.

>>If you DO want a fire for aesthetic reasons, is there a way to "bypass" transferring so much of the heat to the masonry via a fan or different duct?

The custom-built heaters often include dampers to bypass the masonry mass, or to let you run a small fire in a cooking oven/stove without firing the heater, but this one uses a prefabricated modular heater core and is pretty basic, so no bypass. We thought about it, but since I have the chimney pretty far away from the heater core there was no obvious way to put in a bypass.

The really fancy custom-built heaters have benches (heated with smoke channels) poking off into other rooms, coils of pipe for hot water, ovens and smokers built in so controlling all the dampers is a bit like operating an old steam engine.

>>Or, would you have to walk around in your boxers for three days because the place is too hot?

Of course not, I have air conditioning

Seriously, masonry heaters require a bit of planning ahead, and if the weather suddenly turns warm after you fire the heater you might need to open a window or something. The nice thing is that since so much of the heat is radiant (ie the air temperature might be lower than normal but you still feel toasty warm) this isn't as much of a problem as you might expect.

I wanted to build at least one conventional fireplace into the house so I could keep a small fire going for aesthetics, but the house was already way past my original budget and there was just no way I could add anything else.

My original plan was to start with just a big daylight basement, subfloor and tarps over the subfloor, finish one corner with a small gas heater and a big-ass woodstove, and live in there until I had more money saved up and knew what I wanted the rest of the house to look like. Unfortunately existing zoning laws prevented me from living in a partially-built house (that used to be a fine old tradition in Toronto) and newly passed laws meant I needed to build *now* or lose the ability to get a building permit.

>>By the way, what is the temperature during the day in your neck of the woods this time of the year. It won't be long and you will really see the benefit of having a heating system like that in place.

This September has been warmer than normal, typically 70 during the day and 50-60 at night. Right now I am just running baby fires to make sure the mortar is dry.

I also need to buy firewood, which seems crazy since the house is in the middle of a forest, but the heater needs seasoned firewood because of all the twisty smoke channels. Apparently the norm for these heaters is to have the chimney inspected every year and cleaned perhaps every 10 years -- the firebox gets very hot so the fire burns cleanly.

Sounds like your weather, at least for now, is similar to ours seen typically in Missouri at present time. You mentioned that you need to buy cured wood. I guess cleaning the creosote from the flue channels could present some challenges, especially if it were an elaborate configuration with all the options.

Fantastic home - and I love the heating system!!! From what I've read, your only other source for heat is the electric infloor heating in the bathrooms, is this correct? Do you have a back-up heat source in the house? From some of your other posts, I gather you live in a fairly isolated area outside Toronto. What is your plan when/if you leave the house for extended periods during the winter? I assume you have a friendly neighbour who could light a fire in your house every few days if you spend a week or 2 in sunny Mexico during the winter? Actually, I'm in Sudbury, and a week or 2 near Toronto in that beautiful house would be like a holiday for me... and I know how to light a fire... I might be onto something

Thanks !!

When the house was being designed I organized an impromtu "design committee" including, among other people, a family friend who was also my real-estate agent.

"The committee decided" that the house would also have a conventional furnace. I went with propane for convenience -- it's more expensive per BTU than oil but the masonry heater will carry much of the heating load. Also, it seems that insurance companies strongly prefer wood heat to be secondary, not primary.

If I go away for more than a few days I have someone stop by periodically and make sure the furnace is still running. If I ever get time off to take a real vacation I'll give you a call

>>I guess cleaning the creosote from the flue channels could present some challenges, especially if it were an elaborate configuration with all the options

Exactly. Burning it out seems to be the only practical option, and even a masonry heater has a tough time surviving a creosote fire undamaged. When you need to run a heater on uncured wood, the most common solution seems to be the "Russian Heater" approach, where the smoke channels are horizontal and easy to access. Normally Russian Heaters are built entirely from brick, so the mason just leaves one or two unmortared bricks at the end of each channel. When it comes time to clean out the heater, you just pull out the loose bricks and "presto" you have a cleanout. If you want to be fancy you can use cleanout doors

Very cool John. I haven’t seen one of those before. A friend of mine just built a home and put in a beautiful soap stone fireplace from Sweden I believe. Same principle: thermal mass. They had to design the foundation to support its weight.

That sounds like a Tulikivi from Finland ?

That was what I had my eye on initially. They are beautiful, but even more expensive than a built-on-site heater (since everything has to be shipped from Scandinavia) and I have to admit that soapstone wouldn't have fit the style of the house as well as a big stone-covered monolith.

My original sketches for the house had a straight-walled two-story great room with flaming torches around the periphery, a walk-in fireplace and a chandelier about the size of a mid-sized car. It was immediately vetoed by the real-estate agent

I suppose you had to rename the Dungeon, too.

Yes, it is now the Treehouse (loft) and not nearly so interesting. On the other hand I should have a loaned minibar fridge and hotel lobby wheeled bar up there in a week or so (piano didn't quite fit so in goes the bar) so it's not a total loss.