Great post on a serious subject. I had a CO detector in my garage in my old house where I brewed and will be getting one for the new house's garage, too. I spent one holiday season working part time for
First Alert, helping out with answering their help line. That's their busiest time of year. I learned a thing or two in my short time there.
Carbon monoxide is the #1 cause of poisoning death in the US. It can be given off by home appliances or even a car in an attached garage. Most people that have an alarm go off think their alarm is defective when, in fact, they really do have a CO problem. 90% of the calls I got when I worked for FA were of that nature.
If you have a newer home, you're even at more risk because most newer houses are built better than they used to be. With better insulation, more precisely made doors and windows and better construction methods in general, homes have less leaks than they did 20-30 years ago. That's great for your energy bills, but leaves any trace of CO trapped in your home.
If you brew in a basement, garage or any enclosed or even semi-enclosed area, a detector is a must. It's damn cheap insurance, especially now that they are much more accurate today than they were just five years ago.
And a big word of advice. Make sure and get a detector with a battery back up. There
are a couple of cheap models still on the market that only run on the AC in your house. If you have a power outage, those detectors are rendered useless.