We don’t have any but we don’t have a furnace nor an enclosed garage. Lucky to live in HI.
Do you have gas appliances? Those can produce CO as well. (Driers, ranges, etc)
No gas appliances–would have to get a huge tank on our property. We have solar and photovoltaic and pretty much no energy bills.
Your dad is very lucky! I ran in to that CO detector end of life issue not too long ago:
http://talk.collegeconfidential.com/parent-cafe/1832406-co-detector-end-of-life-p1.html
Ours is hardwired into the house and is part of the security panel. I have no idea how to test them to see if they work, though. Do hardwired ones have an expiration date, I wonder…
I know hard-wired smoke detectors have a finite life. Our smoke detectors started chirping at random times, looked them up , and sure enough, that was a signal to replace them.
The newer codes require the hardwired ones to also have a battery in case of a power outage. We bought a new home last June and the sellers had to install five combo smoke/carbon monoxide detectors. I think only two are hardwired–the ones in the hallways on each floor.
Make sure your kids have them in their dorms or apartments. A few years back (2005?) in a new apartment complex at UVM, a friend’s daughter spent weeks in the hospital, and a young man visiting her died, from carbon monoxide poisoning due to faulty ventilation. In a matter of days the entire campus was outfitted with new detectors.