How A Wood-Stove Catalyst Works

Just How Does A Catalyst Work?

Some EPA certified wood-stoves have a catalyst, however a catalyst is not a filter.  In fact if it were, it would more than likely need cleaning or replacement more frequently than it does.  The catalyst does not capture and hold nasty material, instead there is a chemical reaction that reduces combustion temperature and the nasty stuff is actually burned.   The platinum in the honeycomb structure of the catalyst cause or create this chemical reaction that takes place, allowing the catalyst to turn combustible gasses in the smoke into water vapor, carbon dioxide, and HEAT..  You may have also heard about a catalyst or catalytic converter in your automobile, which are used to reduce emissions.  However, the wood-stove catalyst not only reduces emissions but also takes that energy and uses it to contribute HEAT to your home, also increasing the efficiency of the stove overall.  A working catalyst will have invisible gas and white water vapor (steam) coming from the chimney, if you see dark smoke from your chimney, this is a sign that the catalyst is not working properly.

Whys Is There A Bypass For The Catalyst?

The catalyst can not operate below a specific temperature, knows as “light-off temperature”  This why a bypass is provided for lighting the fire and the warm up period.  This temperature is around 260° Celsius.

The actual catalytic reaction temperature will reach a maximum temperature of around 700° Celsius.   In fact exceeding this temperature can be destructive to your stove.

Does an Advanced Chimney Sweep make one better?

Have had a few ask about the Advanced Chimney Sweep and why or what makes it better.

I like to be up front and honest – it is a good marketing tool – but honestly there are sweeps out there who are Certified Sweeps (without Advanced status) who are every bit as good a sweep as those with the Advanced status.

It really means one only did perhaps a bit more book work and scored better on exams.  More head knowledge and more bookwork.. but does not guarantee a better worker in the field.

How do I know?  I am an Certified Advanced Chimney Sweep – and I know several who are only Certified Sweeps and would tell you in a heartbeat they are every bit as good at what they do as am I.

Bad smelling firewood.

Have had customers from time to time mention the smell of firewood.  All firewood stored outdoors will have some humidity in it even when seasoned; and with that some wood can carry an odour.

Even when wood is down to 20% level of moisture – which is considered seasoned by the woodstove manufacturers – it can still contain enough moisture to emit a smell.

Some wood is worse than others – one we have around here that can smell bad is Red Oak.  Best to not put the wood indoors – some like to store inside – but please know in advance it can smell.

Also note that storing wood indoors – on any wood or woodstove site – will NOT be recommended for a few reasons.  In fact I don’t think I have ever seen a reputable site which recommended storing inside – reasons to not do so include.

These include – adding moisture to your home – making the firewood too dry (yes it can be too dry and there are other blogs I have explaining that) – adding unpleasant odours to your home – bringing pests and insects indoors with the wood – potentially causing a fire hazard (do not stack close to heat – wood stove – in fact in most cases keep back 48″ from stove).

So yes there can be nasty odours from firewood – some worse than others.  Oak in our area can be one of the worst – yet is also a highly desirable wood.  If you are going to bring it inside – despite all the above – try to tell the wood supplier you do not want any oak in the mix.

Building a Rumford Fireplace!

Are you thinking of a fireplace in your home, or maybe have one and it simply does not provide heat!

Ever consider the Rumford?  Ever hear of a Rumford?

A Rumford is an old designed – designed to heat the home rather than the outside.  But the Rumford with the tall openings creates a beautiful and efficient fire that you and your family will love – and the shape of the opening will ensure you get the most heat from the fire as it burns.  Your friends and family will love. The unique shape ensures that you will get the most heat out of the wood you burn.

You see Count Rumford understood that the only really useful heat generated by any fireplace was the radiant heat. Any air that was heated by the fire simply went up the chimney, he therefore worked to design a fireplace with a large opening – which was fairly shallow – to reflect as much heat as possible back into the room.

The problem with the design is that a tall, wide shallow fireplace by design will tend to smoke, making the room uncomfortable. However, keep in mind that Rumford was a physicist and understood fluid dynamics – in fact he was way ahead of his time – in his design he essentially created a venture or nozzle which essentially will pull the smoke up through the throat into the receiving smoke chamber.  Because of this in the Rumford design the smoke is effectively pulled out the chimney instead of lingering and entering the room – an added benefit for those new to lighting a fireplace.

The problem is that is not the way masons were trained and many masons today, who are trained to build modern fireplace will have trouble believing a Rumford will draw – that is until they see it work.  You see the rules and Building Codes are different – in a modern fireplace the fireback is usually sloped forward pushing the gases from combustion toward the front, the incoming air from the room flows over the steel lintel and mixes with the heated gases, causing a turbulent smoky mixture.  Most masons, who while good at their job, do not understand fluid-dynamics and will tell you that you need to “cross over” or drop the lintel about 200 mm or so below the damper which will create a pocket for this turbulent smoke – or else there will be smoke coming out of the fireplace opening.

Because of the design, the opening into the chimney is only half as large, it takes more room for this turbulent air to get out.  It is a more efficient design, invented by a physicist.   The Rumford is more efficient, radiates more heat and wastes less heat to the outdoors.  Frankly, other than for aesthetic benefits one wonders why the modern fireplace design ever came into existence – it really was because an architect liked the looks – did not care about efficiency and designed around looks over performance.  It is rather unfortunate as our whole system now has grown accustomed to this design and feels there is no other that will work!  And a poor design it is – built on looks versus function – and with a Rumford you can actually have both!  Yes the Rumford – although not today considered traditional can be a beautiful and a functional fireplace which can heat the home efficiently.




The Spazzacamino Chimney Sweep Festival

A popular festival for Sweeps from across the globe.  The Chimney Sweep profession is respected and celebrated in Europe and has an an

nual festival in Italy.  The 4 day festival is an opportunity to get to Ita

ly and enjoy the sights and the festival.  This is an annual festival; and Cherry and I love Italy as our favorite vacation spot.  Actually southern Italy is

the most favored area, but northern Italy is great as well – and once in the North why not go south for a couple of nights before the flight home.  Oh, she does hate that flight!

What is a Rumford Fireplace?

What is a Rumford?  In fact you may have one and not even know it.  Really it is a fireplace design by Sir Benjamin Thompson, Count Rumford; an American born physicist and inventor whose challenges to established physical theory were part of the 19th century revolution in thermodynamics. His work involved a wide area but include gunnery, explosives, insulation and heat. And of course the fireplace design named after him – the Rumford.

The Rumford is a fireplace that works, and an existing and possibly compromised fireplace can even sometimes be turned into a Rumford.  The Rumford was popular when peopled heated with a fireplace instead of using it for visual entertainment.  But in the environment of high electrical costs; you want the heat from your fireplace!

Yes the modern fireplace has a stylish look, but frankly they don’t work.  They quite simply are not as effective as the old classic Rumford.  The Rumford has been with us a long time, invented in the 18th century.. and yet it still works better than the traditional fireplace of the 21st century – which often time sends much of the heat skyward.

In design the Rumford was about as wide as it was high, the total depth and width of rear wall is approximately 1/3 the width / height of opening – note by Ontario Building Code this must be at least 300mm in depth.  And the back wall is vertical in design.

Get professional help and get a Rumford – and heat your home in style and a traditional working fireplace.  Get a Rumford.  More heat and less smoke!

How Does A Wood-Stove Work

Wood-stoves today can complement almost any décor, can be highly efficient and one of the lowest net contributors to green house gasses available.  Are they for everybody?  No, and there are reasons for that, but where they work they are a great alternative.

­What does the word wood-stove bring to mind?  Perhaps the “roaring fire”, the “incredible warmth”, the “glowing dancing, flickering flames”.  Whatever it is, many of us enjoy wood-stoves for varying reasons.  Wood-stove industry has made incredible gains in the past decade or two, and if your wood-stove is over 20 years old, it is likely time to consider replacement.  While you may consider replacing an appliance to save energy costs, many forget about the wood-stove as it appears to be old-technology.  In fact the wood-stove has made perhaps greater gains in efficiency and pollution emissions in the past two decades than any other home appliance.

However, the same can not be said of the fireplace.  An open fireplace is notoriously inefficient, and some of them can actually make your home colder.  The use and idea of a fireplace is actually not in anyway related to efficiency of green house gas emissions.  They can be made better with a fireplace insert, and an insulated chimney liner, but still not as good as the best EPA certified wood-stoves.

Fact is for most people, the best option for flexibility, cost, efficiency and green house gas reductions is the certified wood-stove.

The Chimney


If your chimney is not working properly; neither will your wood stove, fireplace or furnace.  Without a good chimney the rest does not much matter.


  • the right chimney for the appliance is is serving;
  • sized correctly for the appliance – most often the same size as the appliance outlet collar;
  • located and positioned properly – generally within the heated space of the home (or if exterior then at least insulated);
  • installed properly – as per manufacturers instructions, Ontario Building Code and CSA B365 – which ever apply for the particular chimney.


  • allow fires to be lit easily and have a good draft
  • will not fill room or house with smoke when lighting a fire
  • will not spill or puff smoke back into room when door of wood stove is opened
  • will not emit foul stinky odors or a cold draft into the room when not in use

If you are planning to have a wood burning system installed.  The first critical component is the chimney.  Get reliable advice on the type and location of the chimney to be installed.  Most wood heat retailers and chimney sweeps can provide guidance in this area.  For most people it is preferable to have a professional install the chimney versus doing it yourself.  Once installed you MUST have a WETT Inspection – and you will need to find a WETT Certified Chimney Sweep, WETT Certified Technician or WETT Comprehensive Inspector to do this – the SITE BASIC Inspector is not permitted to perform inspections on new installations.


  • If there is no fire burning and the door is open, air should flow into the stove – not out.
  • When you light kindling the smoke should flow toward the chimney, not back into your face.
  • Kindling when lit should burn with a bright hot flame very quickly.
  • A properly built kindling fire burns bright and hot very quickly.
  • If operated properly there should never be any smell of smoke in the house.


If the chimney is the engine, then the fuel it needs to work is heat.  The more heat the better and more it works, however a good chimney really will not need much heat to work properly.  The more heat you put into it the more draft or power the chimney will deliver.

The stove helps the chimney produce more power (draft) and the chimney in producing the draft helps the stove work better.  The two of them in a good system work hand in hand.  A chimney that is interior to the home or one that is insulated is able to product more draft with less heat in is essentially a more efficient producer of energy/power (draft).

Chimneys do need heat to work properly and in doing so they do rob the home from heat.  Most chimneys need around 20% of the wood heat, which means that the stove is unable to send more than 80% into the home.  However, the more efficient the chimney is, the better the system functions and the more heat you have inside the home for each stick of wood burned.  Because the chimney needs the heat, stoves running much over 80% tend to have water vapor condensation inside the chimney, especially on exterior masonry chimneys.  Do not starve your chimney of heat as it does need heat to function properly.

In winter, a well-designed and properly installed chimney will always make draft and upward air flow, even without a fire burning.  When a fire is lit, the kindling ignites and burns easily, draft increases quickly and there is a nice, bright, hot fire immediately without any smoke in the house.


Warm air inside the house wants to rise, and pull in cooler air at the lower points of the home.  This is a naturally occurring air flow in any home and is called stack effect.  The cooler the outside air, the stronger this air flow and pressure differential becomes.  The top of the house has a higher pressure and the basement a low pressure, in the middle of these two zones where the pressure is equal to outdoors is called the neutral pressure plane.  This pressure plane will move up and down in actual location in the home depending upon temperature differentials between inside and outside, the operation of exhaust fans in the home, etc.  If the home is tightly sealed this pressure can build to a greater degree and turning on exhaust fans in a tightly sealed home only exaggerates this further.  If the wood stove is situated in the basement, the lowest pressure point location and this pressure differential becomes high enough, air can be drawn in through the chimney in a reverse direction – sucking smoke and flue gases into the home with it.  In this example, you would need a very good chimney and wood stove to enable overcoming this situation at all times.


1. Cold hearths and odors: when no fire is burning, cold air and/or odors seep from the stove.

  • The air in a chimney that runs up the outside of the house gets chilled, so the draft in the chimney is less than the stack effect of the house, and the chimney backdrafts, making the hearth cold and causing unpleasant odors
  • Cold backdrafting can also happen if the chimney penetrates the warm part of the building below its highest level, which it will if the hearth is installed at the low side of a cathedral ceiling, or in a single story section of a two-story house
  • Install the chimney inside the building and have it penetrate the warm space at its highest level and it will make draft, even when no fire burns

2. Open door smoke spillage: when you go to reload, smoke rolls out the door.

  • When you open the stove door, a lot of dilution air must flow through the opening to keep the smoke inside; if the exhaust flow is restricted, smoke will roll out into the room
  • Go straight up, if possible; avoid 90 degree turns in the flue pipe and offsets in the chimney

3. Sluggish performance: smokey fire, hard to get a hot fire burning.

  • Large, cold chimneys, like old brick ones, suck up the heat from the exhaust, causing slow draft build up.
  • Size the flue to match the stove and use an insulated chimney to keep exhaust hot and moving quickly; never use an air-cooled chimney


1. Put the chimney inside the warm building environment
2. Go straight up, no elbows or offsets
3. Insulation around the flue liner
4. Flue sized to match stove


Follow the design guide carefully or during our cold winters you will be sorry. Good design will pay off.