I would have been concerned, except for the fact that this is the third time in a year the detector has gone off.
The first time, we learned that the more than 5-year-old detector was likely at the end of its lifespan. Other unit owners in the condo complex had had to replace theirs, so we replaced ours with a new one.
The second time, about 6 months later, our first tenant was living in the condo. She called the fire department before she called us. And the fire department didn't get any reading of carbon monoxide in the condo. After testing the battery and seeing a full charge, we felt that the detector must have been faulty. I was able to exchange it no problem at Home Depot.
This most recent time, the third time, we have replaced it again, but now I'm getting suspicious! Again, it was definitely not a battery issue. The detector had a recent manufacture date on it, so it can't be at the end of its lifespan.
I'm wondering if, because of the small size of the condo, the detector is too close to the furnace or the vents? I'm not sure that it could really be moved any further from either.
The detector we have been using is a combination smoke detector and carbon monoxide detector in one. It is hardwired and always has a new battery in it for backup. The brand is Kidde.
I'd be so interested to hear if anyone else has had a similar experience?
In the meantime, we've left a plug-in detector at the condo as well.