I do not know if this subject is covered here but reading the "downdraft" thread inspired me. I have two smoke/carbon monoxide detectors in my house, one upstairs and one in the basement. I strongly recommend carbon monoxide detectors in addition to smoke for anyone burning firewood. We had a downdraft bring CO from coals inside.
We have detectors at the top of our basement steps, one at the peak of a vaulted ceiling where the wood stove is. One outside the 2 bedrooms, close to ceiling. And one in our bedroom, just above pillow height. None are hardwired.
Understand the home detectors are only for extreme amounts of CO and often over long periods of time, they really almost don't work. When tested failure was in the 50% range and often didn't activate until levels were far past any safe values. This is do to lack of appropriate regulations of the quality of consumer detectors sold at big box stores, and a misinterpretation of acceptable exposure levels. I use one of these to monitor levels at home, and when working on old HVAC units. I would never personally rely on one of those home carbon monoxide detectors. Inspector - Intrinsically Safe Carbon Monoxide Detector & CO Meter (CO Ind) In my research 30ppm for 8 hours one day a year is all you'd really want to be exposed to for good health. Most home detectors kick in at 50ppm after 8 hours and won't sound until after 30 days sitting at 25ppm. You won't die from constant exposure to 25ppm, but you probably won't feel great.
years back when CO first came to light being an indoor issue i bought a detector for my dad. My electrician friend direct wired it. Dad's aftershave would trigger it every night and it wouldnt stop. In despair we would wrap it in a plastic bag. It didnt help. Darn thing would go on forever it seemed!
We have one with a digital readout. To test it I've had to put it right up against a car exhaust. We also had CO-only detectors right over the beds in the bedrooms, but they got to be ten years old and started end-of-life beeping so all the smoke alarms have been updated to combo units. No more AA battery detectors. Except for the one with the digital readout- that stays near the wood stove. My boiler has a wired combo detector integrated with the control board.
That's one reason I like my non-tight housing envelope--all my windows leak just a little bit. And my wood stove does not have a dedicated air line to the outside.
The digital readout will only start reading at 25ppm after 30 days or 50ppm after 8 hours, it's not a real time readout. Low level detectors are my recommendation. Not trying to be a negative nancy, just pointing out the home detectors are not exactly what people think they are, and often defective do to design or age.
Is CO emission an issue with a wood burning stove? Don't get me wrong, I think having a CO detector is a good idea, I have one, but I mostly worry about CO because of my gas furnace (which is almost never used) and other gas appliances. The primary gas released from burning wood is CO2, not CO. Sure some CO is emitted, but I don't worry about that when standing around a fire outside and breathing in tons of smoke when the wind changes direction. The amount of smoke leaking into my house from the wood stove is surely minimal compared to standing around an outside fire. So while I think a CO sensor is a good idea, I don't have it because of the wood burning stove. When I was first learning to use my stove lighting fires with no coals/ash, and I would get smoke in the house, and the smoke detector would go off, not the CO detector which I had in the same room as the stove just to test. I think a smoke detector in another room will go off well before a CO detector in the same room as the stove.
CO can be produced by any fuel that has carbon in it. The normal product of combustion is CO2. CO is produced when the combustion process is not completed properly. If the fuel is starving for oxygen cause by any interruption of the air intake flow or by the exhaust or flue being blocked or partially blocked, CO can be produced. Large amounts of smoke need not be present. I believe in a wood stove the most dangerous time for CO to be produced (other than a blocked chimney) would be when the primary air is turned way down and the fire or coals are about to go out. What is Carbon Monoxide and what produces it? This has a little more info about the production of CO.
An airtight wood stove or furnace produces much more CO than a gas or liquid (fuel oil) fuel appliance. Wood has a higher carbon content than liquids or gas. Liquid and gas appliances get better air:fuel mixing at the ignition/flame front compared to burning a solid fuel. Operating a stove on coals at reduced draft reduces the stack temperature. A house has a natural "draft". I lose a little air out of the bathroom and kitchen vent flapper valves. If the wood burning appliance stack temperature gets low enough and so reduces the chimney draft below the house draft then the chimney can reverse. External chimneys are also cooled by outside air more than a chimney going through the roof and so are more prone to have too low a draft relative to the house natural draft and so reverse. A basement wood burning appliance chimney draft has to exceed the entire house natural draft while a stove on a higher living level would need to exceed only part of the house natural draft. A VERY air tight house can have an interesting battle between wood burning appliance draft and a house natural draft and so many very air tight houses have an external air source for their wood burning appliance (which some building codes mandate).
The good thing about wood burning, CO will almost always come with smoke and the associated smell. A bad heat exchanger or improperly vented hot water heater, will pretty much never produced any smell or smoke. The only time my CO meeter registers anyting from my wood stove is when I light a fire, which is always a company with the smell of smoke. A good thing to do IMHO when you're burning, is to always have a small window cracked just a hair somewhere in the house, especially if the house is sealed up nice and tight.
I have have multiple smoke detectors. I have a C0/c02 detector in the hall outside all our bedrooms too. I think it cost about $20-30 or something like that. Too cheap to not have and burn wood daily. Too much too loose. It’s about risk reduction.
Timberdog, it's the cheap ones you need to worry about. Tests were done years back and found many that were brand new, just pulled off the shelf of a big box store and others taken out of houses where they were installed within the past year or two, did not work at all. Aside from that, most are configured to avoid nuisance tripping, like from the aftershave, which makes you take the battery out or turn it off. They generally don't alarm until the reading reaches 70ppm and stays there continuously for a full 3 hours, unless they go up really high, then they may alarm right away, but again, only if the sensor is actually working. You could have chronic, intermittent low levels, low enough that it will never alarm but high enough to cause brain & nervous system damage over time. The other bigger factor that isn't advertised for some reason. The test button, does not test the sensor, at all. It tests the power source and beeper only. The only way to test them is with a test gas. At the very least, the ones with a Peak Level digital readout are the better of the cheaper ones but the low level detectors are worth the extra money. I could tell you story after story of Carbon Monoxide poisoning from my work. Yes, mostly from gas appliances but not impossible with stoves. Couple years ago it happened to a friend with his pellet stove from a dirty chimney.
Locally there was a young couple and their dog deceased from CO poisoning after installing a new coal stove (furnace?) a couple years ago... MAF143 probably remembers hearing about that one...and I think walt said he knew the family.
