Pros and Cons of Masonry Heaters

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Masonry heaters are wood stoves with the welded steel or cast iron casing replaced by bricks and mortar. They are very efficient at warming an entire house, producing much higher temperatures from their fuel than standard metal stoves. Like all forms of heating, they have certain benefits and drawbacks.

The advantages

  • They use a renewable fuel which is abundantly available and easy to source. They are therefore incredibly sustainable.
  • Masonry heaters serve a double purpose: they can act as backup heat for a passive solar home and as a primary source in times with little sunlight.
  • They come in designs and sizes suited to everything from a single room to an entire house of 2,000 square feet.
  • They are very easy to operate – no more difficult than a normal wood stove.
  • They use 35-50lbs (16-22kgs) of wood per firing, usually twice a day in heating season, providing enough stored heat to last the whole 24-hour period.
  • They are very efficient and produce very little pollution.
  • They burn so clean that they are exempted from wood-burning bans (even in Washington).
  • They fall into the super-low-emissions category.
  • Masonry heaters are safer than wood stoves because there is no risk of creosote fire.
  • They require little maintenance – every five or ten years is essential, though a yearly clean is often worth the effort to keep things quick and easy.
  • They are cooler to the touch than most wood stoves (around 155°F to 175°F, or 68°C to 80°C). Historically, they used to have benches built into them.
  • The air is not directly heated by the stove, so still feels fresher and cooler. They do not cause drafts.
  • You can install a damper to shut off the flue when the fire is out, which also improves the chimney draft at lighting, and protects the chimney from rain, snow, birds, and strong downdrafts (assuming it's a rooftop damper).
  • They can be installed with glass doors so you can see the fire. They can even have pizza/bread ovens built into them!
  • You can buy plans and build one yourself.
  • They are very aesthetically pleasing and, unlike most stoves and heaters, can form an attractive centerpiece to a home.


The disadvantages

  • Masonry heaters are not easy to source in the USA (though much easier in Europe).
  • They require someone's active presence and cannot be used for backup when you're away.
  • They produce delayed heat – firing in the afternoon will heat in the evening and night, depending on the mass of the heater.
  • They must be very carefully sized. High-mass heaters provide more heat for longer. Most models weigh in at 2 to 4 tons, though smaller options for mild climates and truly massive designs (up to 8 tons) for very cold areas also exist.
  • Masonry heaters are very heavy, so they often require beefed-up foundations. This makes them hard to retrofit.
  • They must be airtight when built.
  • They must be built of materials which can cope with significant expansion and contraction – and the installer must understand the needs of such changes.
  • Facing materials must take