- Knowledge & Experience
No wood burning stove, fireplace or furnace can function properly without a good chimney. A good chimney is:
A good chimney and system design produces desirable performance characteristics:
When planning a wood burning system, the first thing you need is reliable advice on matching the appliance to the right type and size of chimney. Most wood heat retailers and chimney sweeps can guide you and there may be government agencies and publications you could get locally. Also, unless you have done it before, we strongly recommend having your chimney professionally installed by someone whose references you have checked. You never want to lie awake at night wondering if an incompetent chimney installation is putting your house and family at risk.
Think of the chimney as the engine that drives the wood heating system. Think of its fuel as heat. Think of the power it puts out as draft. The more fuel (heat) you give this engine (chimney), the more power (draft) it will deliver. So, the hotter the exhaust gases, the more draft is produced. Draft, by the way, is good. It’s the suction that keeps the smoke from coming into the room. Insulation in the chimney is important because it helps to keep the exhaust hot until it is expelled outside, and so, increases draft.
The chimney works with the stove or fireplace in a kind of feedback loop. Heat in chimney makes draft, which pulls in more combustion air, which makes the fire burn hotter, which delivers more heat to the chimney which makes more draft and so on. An insulated chimney makes more draft with less heat.
In winter, a well-designed and properly installed chimney makes some draft and flows some air upwards, even when no fire is burning. When you build a fire in a stove connected to such a chimney, the kindling ignites easily, draft increases rapidly and you have a nice bright, hot fire right awayâ€”and no smoking. This is the kind of system you want in your house.
When it is cold outside, the warm air inside the house wants to rise, producing a pressure difference: low pressure low in the house and high pressure high in the house. The pressure difference is called stack effect. The colder it is outside, the greater is the temperature difference, so the stronger is the stack effect. A chimney installed in the middle of a house naturally overcomes stack effect by being as warm, but taller than the house.
Houses are being built more tightly sealed for increased comfort and lower energy costs. This is done by using doors and windows with gaskets and walls with a continuous air barrier (usually plastic film). If you turned on a powerful range hood or downdraft kitchen exhaust in a relatively small, tightly sealed house, it might suck so much air out of the house that the pressure inside would fall enough to overcome chimney draft and suck the smoke out of the stove. It’s not that common yet, but it can happen.
If you live in an area that has a real winter “ the ground freezes and you get some snow “ or if you live at high altitude “ say more than 4,000 feet “ you’ll need to follow these design guidelines exactly in order to get perfect performance. You people at low altitude with mild winters may not need to be quite so fussy, but, then again, good design always pays off in better performance.
Call Roger today to book your WETT Certified Inspection of Wood Stove, Fireplace, Outside Boiler or Pellet Stove. We service Angus, Alliston, Barrie, Thornton, Tottenham, Beeton, Orillia, Midland, Penetang, Wasaga Beach and Elmvale.