In my state, new CO detectors are required to have 10 yr sealed lithium batteries, and they self-expire themselves. If addition, if it is a combo CO-smoke detector, it is required to talk to you to tell you which alarm is going off. If you are buying new ones, check the current codes in your state first.
You don’t want a CO detector right next to or above the furnace or other gas fired appliance because they can often leak a small amount to CO when they start up, which is not dangerous but can cause false alarms and many people will just remove the detector rather than move it if it frequently false-alarms.
CO detectors have an end of life warning, which is a chirp every 30 seconds. The first time I heard this I thought it was just the battery, but learned that it was actually the CO detector telling me it was dead. They used to have a 7 year life (and 7 yr warning). Since 2013 they have been making them good for 10 years.
We have 2. One is in our master bedroom on the first floor. The other is in my son’s bedroom on the 2nd floor.
We had an alarm go off once when our furnace broke. Something was installed incorrectly, so when the furnace broke and started to generate CO, it was vented into the house. Lucky we had the detector!
We have a one-story house and have two CO detectors. One is in the hallway outside the master bedroom and the other one is in the hallway outside the other two bedrooms. We have separate hardwired smoke detectors in each bedroom as well as in the hallways outside the bedrooms.
It is embarrassing to admit how long it took three of us to identify the source of the chirping expired CO detector. It has been plugged in behind a shelf near the oil burner for ten years, so it was not visible AND it makes the same sound that the hard-wired smoke detectors emit.
So, one new detector near oil burner in unfinished section of basement. Building code required a combustion air source thing. (Perhaps @mathmom can help me figure out what I am trying to say.) It is this tall silver pipe that I think brings in fresh air? I think the town expects residents to box in the HVAC equipment and finish off the entire basement after they sign off on the CO, but we never did.
I have a second detector in the kitchen and a third up on the second floor in the hallway outside the bedrooms. Since it is two full floors between the oil burner in the basement and the second floor bedrooms, I don’t know if that third detector is overkill.
Some CO detectors have a display that shows detected CO level, which can be helpful to notice small amounts of CO that are below the alarm threshold, but could suggest a small problem that could become more dangerous later.
Regarding smoke detectors, it is recommended to have both photoelectric and ionization detectors (or dual-sensor detectors), since photoelectric detectors respond faster to smoldering fires while ionization detectors respond faster to flaming fires.
@CT1417 that silver pipe might be your combustion air source. In an unfinished basement with insulation on the ceiling it can just be a grate. If you use your basement your probably don’t want a hole letting cold air in so most people either insulate their furnace room or put what we call around here a “fan in a can” which is hooked up to the furnace and provides air on an as needed basis.
we have a gas furnace in the garage, so only one CO monitor in the house. Recently had the duct work replaced so same the forced air from the furnace goes to all BR’s. Not sure of the need for more than 1 monitor.
@bluebayou Do you have a gas stove? Can you guarantee that gas from your furnace could never ever possibly get into your ductwork? You should put a CO detector near your bedrooms. They are a cheap investment.
nope, electric kitchen. But good point I hadn’t thought about.
Not sure I understand the question. Furnace (and hot water heater) are in attached, but airy garage. If either leak the gas will just escape. (Replaced the HVAC along with ducts last year, btw.) OTOH, by definition, the forced air blows thru every duct. So, if a gas burner is bad, any CO will automatically blow into every BR. So, we just have the CO monitor in the middle BR.
@mathmom – Yes, I recall it being named a Combustion Air Source, but when I googled that term, did not find anything similar to what I have. Your description is correct. It has a wider base and then ductwork that eventually goes through the foundation. I only recall it because the contractor overlooked it on the architect’s drawings and the town inspector forced the contractor to install it.
The unfinished side of the basement houses oil burner, air handler, hot water heater, ejector pump, washer/dryer and far too many storage shelves. The finished section of the basement is above ground due to slope of property. In light of this layout and the fact that we do not have a gas stove, should I be worried about CO emissions on all three floors? Heat is baseboard in basement and on second floor, and hydro air on ground floor, in case that is of any significance.
If you are burning any fossil fuels, or have a garage that is attached to the house in any way, there is potential for carbon monoxide everywhere in your house. The molecules are so small they can pass through drywall.
For the $20-40 cost of one with a 10 year battery, I think you would be crazy not to have at least one on each floor.
We have three - one in our mudroom which attaches to our garage for reasons stated above, one in our upstairs open foyer hallway near the bedrooms just in case (we also have a gas furnace in our attic for the second floor), and one in our basement (near the primary gas furnace).
Both municipalities we recently lived in required a CO detector on every floor (gas heat). Even in the “all electric” condo we recently bought a CO detector was technically needed because there is a parking garage under the building, and the condo allows gas barbecue grills on patios.
We have 4 – one in each bedroom and one in our main hallway. They are actually combination smoke/CO detectors. Ours do talk to us to tell us if they are detecting smoke or CO, and where.