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Tough call: fireplace insert or masonry heater?

High-efficiency fireplace inserts like this can be a great choice for heating, but masonry heaters (in photo below, on this page) are even more efficient, although heavy and costly.

Posted by Nola Poirier

Hey, remember me? This time last year I was shivering, seeking the sunlight that snaked through the window of my freshly purchased, but unheated, Sunshine Coast home, wearing a toque to stay warm enough to type.

Since then my husband and I have been working to make our home energy efficient – and heated. We have a pretty tight budget and we've been doing the work ourselves, but already the benefits are tangible. I'm not wearing a toque while I write (though of course I always wear a sweater and warm socks to reduce my heating energy use).

Last winter we installed some baseboard heaters that my parents were no longer using to keep us warm through the cold snap. But that was our short-term solution. Now, to reduce the energy we use for heat and to diversify our energy sources, we are getting ready to install either a high efficiency insert into our fireplace or to exchange our fireplace with a masonry heater.

Fireplace inserts

Fireplace inserts work much like woodstoves, but they aren't freestanding, they're installed into an existing fireplace. Inserts use a blower to push the warm air into your home instead of having it rise up the chimney.

While an open wood-burning fireplace is typically only 10% efficient at turning fuel into heat, an insert can increase that to between 65 and 85%, meaning your fire will require less fuel, provide more heat, and produce far less air pollution.

I also want to be able to use some of my fire's energy for cooking. With many insert designs, you can use part of the top for heating food, much like you can with a cooking top on a woodstove. Some insert designs stick out from the fireplace, leaving room for warming soup on the insert top. Or you can add a hob, which is a rack that comes out near the top of the fireplace grate, to create a space that can be used as a warming stovetop.

Masonry heaters

Masonry heaters are a highly efficient and very clean way to burn fuel, using a hot fire and lots of air. Traditional designs come from Russia and northern Europe, in particular from fuel-poor areas, because they can create heat from scrap wood, small kindling and vegetable matter.

Masonry heaters use the thermal mass in their brick, clay, or stone materials to hold heat and slowly radiate it into their surroundings, so it is never uncomfortably hot to sit beside them. They are more than 90% efficient at turning fuel into heat. Because of their efficiency, they only require one or two small fires a day to warm a 2,000 sq ft. house.

Many masonry heater designs include a clay oven, that can be located on the same side as the fireplace, or on the back. The backside clay oven would be ideal in my house, as my kitchen wall is on the back of the fireplace wall. And yum, I dream of the possibility of homemade wood-fired bread and pizzas and fire toasted baked potatoes...

Pros and cons

Masonry heaters are more efficient than fireplace inserts and burn cleaner, but they do have a few drawbacks:

  • They are heavy, around 2,720 kg (6,000 lbs), not including the chimney. Our house has a basement below, so the floor would likely need some reinforcing.
  • They are more difficult to install than a fireplace insert.
  • They can be costly, $5,000 – $10,000 and even more if it requires reinforcing your floor.

I'm pretty sure a masonry heater is what I want in the medium to long term, I just don't know if we can afford it in the short-term, and I want to increase my home heating energy efficiency as soon as possible.

There are prefabricated cores for masonry heaters that you can install, and then add the masonry façade, which are said to be just as efficient and can sometimes be cheaper than a custom model, though not always. I have even seen some of the prefabricated cores for sale on craigslist and kijiji, which would help reduce the cost. And some cost increase for a masonry heater would be manageable, but just not too much.

I think we are going to let the floor supports decide. If we have them examined and find out they can bear this, then we can do it too. If not, then I know I would quickly warm up to an insert.

For more information on making your fireplace efficient, check out the fireplaces tip in bchydro.com's home heating Green Guide.

Nola Poirier is a Sunshine Coast-based freelance writer and regular Unplug This Blog! contributor.