Just bought the CO Angel personal CO monitor. I wear it almost all the time now. Walked into an estimate call and the unit alarmed at about 40-45ppm immediately. I asked the owner if he knew he had a CO problem and he said yes. Turns out he was shut down by utility 1 YEAR AGO and a 'contractor' came in, ripped apart the boiler and 'couldn't find anything wrong.' So he fired it back up. Guy has a grown son living in a bedroom adjacent to the boiler room. They also watch a grandchild 3 days a week. The entire house was filled with 40ppm.
This guy was in denial big time, but was convinced about shutting the unit down and we did boiler install one day later.
Me: Just curious, do you have a CO alarm in the house?
Owner: I used to, but it was always beeping and my son couldn't sleep so we disconnected it.
I will be purchasing a CO Angel for all my techs soon- what a great tool.