Masonry Heater (7)
A masonry heater (or masonary stove, ceramic stove, tile stove) is a device for warming an interior space by capturing the heat from periodic burning of fuel (usually wood), and then radiating the heat at a fairly constant temperature for a long period .
Short answer: very. A masonry heater is one of the most efficient cordwood burning devices known...
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Thermal Mass is not an "it" but rather a property, like weight. Every object absorbs, retains and releases stored heat, but some hold more than others. An object that holds a lot of heat energy is said to have, or be, a Thermal Mass.
The simplest way to think of a Thermal Mass is to visualize a dump truck next to a compact car on a flat, smooth parking lot.
The truck takes more energy to get moving, and keeps rolling further after one stops pushing. It has more mass.
The compact car gets moving easily, but won't keep rolling as long.
It's not a perfect picture, but it suffices to get the idea across. Let's take a look at it in woodstove terms:
A metal woodstove is a light stove. Light a fire and it will put out heat very quickly, but let the fire go out and the heat stops just as quickly. The knack for getting a metal stove to heat a home well is to smoulder the wood just hot enough to keep a little heat coming out. This is simply bad combustion. Wood burns better when it can burn hot, but that's a digression.
Let's add some Thermal Mass to the wood stove, say, soapstone. Take a 200 pound metal stove, add 300 pounds of soapstone and you've got a night and day difference. The now 500 pound stove holds heat much longer, keeps the fire going better, and makes the space heated much more comfortable with less re-loading effort.
Let's add more thermal mass and consider an oven or a masonry stove.
3,000 - 5,000 pounds is a typical weight for a masonry heater, though some weigh up to 10,000 pounds. Now we're talking about heat storage. A thermal mass of 10,000 lbs of masonry will hold heat for days!
For ovens and masonry heaters thermal mass = thermal stability. Ovens cook the food after the fire goes out, and heaters heat the house after the fire goes out.
The challenge of good design is to match the thermal mass to the heat output needed. To small an oven and you won't..... (I don't know beans about ovens)
If a heater is too massive you will find yourself living with an unresponsive behemoth. Balancing mass to heat output needed is something that must be considered during the design process. A custom heater builder can match your heater's performance to your desired lifestyle, so that the truck rolls just as far as you need it to for each push you want to give it.
Typically a masonry heater that is sized to heat a whole house will need a concrete block foundation as outlined in our "building codes" section, but in today's high efficiency homes, or with a heater not intended to heat the whole house the framing for the home can sometimes be augmented to support the load of a smaller masonry heater.
Simply visit our member page here and select a company in your area. If there is no company in your area, you can contact AMHOP or one of our members and they will be pleased to point you in the right direction.
There's a lot of different stoves out there and builders of differing levels of proficiency. You don't need a builder with the same level of skill to install some of the kits on the market as you do for a fully custom heater.
AMHOP undertakes a comprehensive review of each applicant for a "heater mason" membership, and only those applicants that meet our standards are allowed to carry the title. Who you hire will depend on your budget, your requirements, tastes, and maybe even your geographical area.
You should be sure your builder has the ability to answer your questions thoroughly and competently. If you are uncomfortable with anyone you've spoken to, AMHOP is happy to offer answers to those same questions in this FAQ page, and in direct communication.
A masonry heater is an investment that will provide long term value, and must be seen from this perspective. Long past the point where you no longer care what you spent on it, a well designed and built masonry heater will still be delivering to you very cozy warmth and using very little fuel to do it.
That said, everyone has a budget of some kind, and so it's a good thing to know what's out there, and what the major costs are to installation of a masonry stove.
There are 5 major components that add up to the cost of a masonry stove, and no matter how each item is approached, there will be some charge associated with it:
Masonry heaters are available as either fixed designs or custom designs. Many of the fixed designs are available as pre-fabricated kits; some of these can be installed by a home owner. Whether you choose to go with a fixed design or a custom design there is a cost associated with coming up with the design. Very rarely will a consumer pay the full cost of design: Even in a custom designed stove, the stove mason will draw upon experiences in the past and will take that into account in designing your stove.
A mass produced "kit" type stove will have a different approach to design than a custom stove, and so you will pay more for the design of a custom stove than you will for a fixed design.
If your stoves comes in a "kit" form, you are paying for a production facility, raw material, and labor to produce the components that fit together to make your stove.
If your stove is "hand built" using commonly available modules this fabrication will involve a single person or a small group working to assemble your stove from basic materials (commonly firebrick). There is variation in construction methodology, so this cost may vary considerably from stove to stove.
Typically you will pay more in material cost to a "kit" type stove, as this cost of production must be met by selling each stove. A "handbuilt" heater will use less expensive material, but will typically have a higher install cost.
There are also kits which use commonly available firebrick for straight walls and supply cast pieces for difficult to build sections of the stove.
The cost of getting the components to you will vary from mason to mason. Some builders use locally available materials to keep costs down, while others will truck material in themselves. The latter gives more builder control over quality and type of materials. It is advisable to use higher grade material in a masonry heater flue system and firebox than is typically available at masonry yards.
A "kit" type stove will typically be shipped on pallets.
Another huge variation from builder to builder. Some methods take a longer time to install than others, and this contributes greatly to the bottom line cost of a masonry heater. A completely prefabricated kit will install quickly, and this cost will be lowest with such a kit.
A custom masonry stove built with imported stove tile and fabricated on site will take weeks to install and a pre-fab "kit" can be installed in just a few days.
How much individual attention does the builder give you as you're choosing your stove? How much will they be available as you're breaking things in to help you through the unfamiliar process? Your "kit" type stove may be customizable, but there's more involved if you're designing from the ground up to suit your specific situation. There's also more decisions to be made!
If you choose a manufactured stove, you'll likely be getting less of these things than you will with a custom stove. This is not to say that you will get a lesser level of service, but that the service will be less involved than would be needed on the other side of the spectrum.
So what does a heater cost?
That's a hard question to answer. You can make it up yourself and take your chances that it will work and spend less than you would on a top of the line metal wood stove, but this approach is more likely to yield trouble than it is happy evenings!
You can also choose to spend tens of thousands of dollars on expensive materials and intricate design, heating a 5000 square foot space.
The cost of your stove will depend on the knowledge base of the person you hire to build it, how big it is, and how intricate it is to build.
I need feedback from AMHOP members on this!
Wood Fired Oven (5)
The interior of a masonry oven heats slowly, evenly, and over a longer period of time by radiant heat. In contrast, an oven made of metal will heat much quicker and is unable to store the amount of energy in the wood, thus the energy is wasted through the walls and by heating air. It is the slow release of radiant heat in a masonry oven that gives wood fired food the taste and texture that differs so much from a metal oven.
A quality wood fired oven is made from quality materials. Your expected use and cooking requirements will also dictate the type of oven you purchase. As your cooking requirements and usage increase, you will want to tend towards a thicker dome and floor to provide more mass to store heat and for more thermal shock resistance. Ovens with thicker domes and floors also tend to be constructed from more than a few pieces which also lends to the longevity of the oven.
Depending on the temperature your oven starts with, and the moisture content of the wood, you can plan for 20-30 minutes to heat up your wood fired oven to cook pizzas or burgers. If you are looking to cook a roast or large quantity of bread, it is best to plan for a little longer heat up time to allow the heat to soak into the masonry mass of the oven.
The best wood to burn in a wood fired oven is a seasoned (dry) hardwood such as oak, maple, or hickory. You should stay away from moldy wood, softwoods with pitch such as pine and hemlock, and especially from pressure treated or painted wood. Any chemicals, molds, or rot in the wood can affect the taste of the food.
If you are burning quality, seasoned hardwood the temperatures in a wood fired oven can exceed 1000 degrees Fahrenheit. This is too hot for most foods, however. You will find that pizzas cook best around 850-900 degrees, meats at 600 degrees, and other dishes around 500 degrees Fahrenheit. As you use your wood fired oven, you will learn to know what the right temperature is for different foods.