Being a chimney sweep and being called to investigate chimneys that are suspected of polluting household environments and applying the methodical process of elimination has lead to some
interesting conclusions that I would like to share. First of all, the poor wood burning chimney gets blamed for everything. We should be thanking the wood burner because years before the carbon monoxide sensor became mandatory in Ontario homes it was already mandatory when there was a solid fuel burning appliance within the home like a pellet stove or wood stove. It has been through investigating the concerns of home owners on the job sweeping that I have been able to deepen my awareness of house system dynamics.
I got a call that a barely used, one year old, high efficiency fireplace was triggering a C0 alarm. Strange, since all new fireplaces in Ontario are required to have an outside air supply connected directly to the fireplace to ensure it has a steady air supply so it will not use up the oxygen in the house and depressurize, reverse the draft or pull combustion air from other appliances like oil furnaces and water heaters and expose the occupants to the fumes of those appliances. In this case, after careful examination of the fireplace and finding everything as it should be I turned my attention to the home. It was new construction and very tightly insulated- as is the trend. There was an HRV (Heat Recovery Ventilation) which is an appliance that exchanges stale air from strategic locations from within the home with fresh air from the outside. I made sure it was turned on and set up correctly because stale air (lacking sufficient oxygen) is carbon monoxide. Consider if you will the off-gassing, contamination of your fridge compressor motor or your propane cook stove. How about your coffee maker, computing devices or your furnace which is basically cooking the dust in the air as it circulates. Do not delay! Go now and open up your windows a crack- do you even remember what fresh air smells like? The mystery continued. The couple with the newborn was still having their Carbon Monoxide sensor sounding the alarm. It kept me up that night. The next time I went back I walked in and there was a door open that I had not seen before. There was a monolithic clothes dryer and it was turned on. How I did not get sucked into the room I will never know.
Contrary to popular belief, the poor, little wood stove and chimney is often not the cause of household distress- rather, it is the 'canary in the coal mine'. It is a common misunderstanding that an HRV will provide 'make- up' air to counteract the depressurizing effects of appliances within the home. Considering the air-tightness of new homes due to building regulations - my question is why are manufacturers of appliances that depressurize the home not require to design air make-up accessories for each and every appliance to nullify the quantifiable negative effect of the products they are selling? It may be the wood stove that gives some smoke or odour that brings the problem to your attention - because a wood chimney that is asking to be swept has a weaker draft and is more susceptible to smoke spillage due to home depressurization. Here is a table flip for you - if your house is sealed too tightly and/ or has chronic depressurization from various sources - that in turn will cause your wood stove to perform with less efficiency, thereby creating even more than normal creosote and requirement for chimney sweeping! Here, now at least some of the myriad sources of depressurization and stale air within your home should no longer be a mystery- not to you, not anymore. Now about that window.....