Catalytic vs Non-Catalytic Wood Stoves: What’s right for you?

by / Friday, 14 November 2014 / Published in Articles, Fireplaces

A wood stove can be a primary heating source for your home or room, adding a layer of ambiance through the crackling of burning wood. Cozying up to a wood burning stove reminds us to stay connected to our families and remember the simple things in life. What is the most important aspect to keep in mind with a wood burning stove when it comes to our loved ones? Safety.

What comes to mind when a wood burning stove is mentioned is a roaring fire; all you need to do is throw in a few logs into it right? Not quite.

Modern wood burning stoves are designed with safety in mind. Modern stoves produce almost no smoke, minimal ash, and require less firewood. While older uncertified stoves release 15 to 30 grams of smoke per hour; new EPA-certified stoves produce only 2 to 7 grams of smoke per hour (EPA).

Wood Stove Comparison

How efficient is your stove?

Emission Limits for Wood Stoves

Wood Stoves are now a much more complicated piece of technology. Gone are the years of just putting a block of wood into a metal container. With EPA’s Emission Limits, wood stoves need to be designed under certain guidelines.  EPA’s mandatory smoke emission limit for wood stoves is 7.5 grams of smoke per hour (g/h) for non-catalytic stoves and 4.1 g/h for catalytic stoves. Stove manufacturers have improved their combustion technologies over the years, and now some newer stoves have certified emissions in the 1 to 4 g/h range.

Two Types of Wood Stoves

Now that we’ve discussed the recent advancements in reducing smoke emissions we can now talk about the two different combustion styles that help achieve these reduced emissions, catalytic and non-catalytic combustion. Both approaches have proved effective, but there are a few performance differences.

Although most of the stoves on the market are non-catalytic, some of the more popular high-end stoves use catalytic combustion. Since they are slightly more complicated to operate, catalytic stoves are suited to people who like technology and are prepared to maintain the stove properly so it continues to operate at peak performance.

Non-catalytic Stoves

Non-Catalytic Stove Diagram

Non-Catalytic Stove Diagram

Homeowners will save money and time with a non-catalytic model over a catalytic model. It is also easier to start and operate, and is ideal for those with less heating demands on their wood stoves. A few key advantages for a non-catalytic stove are:

  • Slightly lower cost
  • Lively flame picture
  • No catalytic combustor to replace
  • Easier to operate

How Does it Work?

  1. Primary combustion air enters the stove and is preheated then introduced above the glass doors. This primary air flow is adjustable and provides control of fuel burn rate and heat output. The sweeping action of the airwash system helps keep the glass clean for better view of the fire.
  2. Jets of combustion air enter through the shoe refractory and maintain a superheated primary combustion zone of coals and burning fuel where combustible gases ignite as they pass into the secondary combustion zone.
  3. Flames entering the highly insulated secondary combustion chamber are further mixed with staged secondary combustion air which provides the optimum level of oxygen to more completely burn off any remaining combustible gasses. This results in lower emissions, higher efficiency and a stable, even heat output from your stove.

Catalytic Stoves

Catalytic Stove Diagram

Catalytic Stove Diagram

A higher efficiency heating machine, catalytic wood stoves are ideal for those who wish to supplant a major portion of their heating needs with their wood stove. A catalytic stove is ideal for those who want more control over their fireplace experience. With a catalytic stove you can look forward to:

  • Higher efficiency
  • Longer burn times
  • Advanced features such as top-loading, swing-out ash pan and thermostatic control

Note: A catalyst needs to be cleaned and maintained and generally needs to be replaced every 5 years or so.

How Does it Work?

  1. Primary air enters the stove through a thermostatically controlled flap in the back and is preheated as it is drawn through the interior walls of the stove and finally to the air wash.
  2. Thermostatically controlled secondary air mixes with the smoke (which is unburned wood gases) beginning the secondary combustion process and providing an optional mixture for greater efficiency.
  3. The mixture passes through a catalytic combustor which lowers the smoke’s burning temperature from 1,200 ºF to 600 ºF and causes it to ignite. This catalytic combustion turns the smoke and other pollutants into usable heat.

 

Cleaner burning wood stoves can reduce your fuel bill, in addition to protecting your health. The Hearth, Patio, and Barbecue Association has developed a fuel efficiency calculator  to show how various cleaner-burning stoves can actually save you money. You can compare the cost of heating your home with wood, electricity, natural gas, oil, or coal. You can also see how using a cleaner burning hearth device to supplement your existing heating system can reduce your overall home heating cost.

A central furnace cycles on and off several times an hour and heats your entire house – even unoccupied rooms – wasting money. Using a supplemental hearth appliance to heat the rooms your family occupies most, or “zone heating,” allows you to turn down the thermostat for the central furnace, decreasing your fuel bill.

The following energy savings calculator was developed by the Hearth, Patio & Barbecue Association and is provided for estimating purposes only. Actual energy savings may vary based on use and other factors.

For more information on wood burning stoves please contact us at 204-667-3330 or fill out the form below.

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