Do you have that Carbon Monoxide detector yet?
If you don’t, especially if you heat with fossil fuels, go get one and 
install it. If you have one installed, pay attention, and take it seriously when it signals an alarm.
Carbon Monoxide (CO) is odorless, tasteless, and colorless so it can accumulate and creep up on you without you even being aware of it. Enough exposure, especially in children and older adults, will make you ill and perhaps kill you. The Centers for Disease Control and Prevention provide a great overview of the risks and the preventive steps you can take to avoid CO poisoning.
Recently the CO detector alarms went off in a client’s newly constructed cottage. At first the security company thought it was a false alarm; perhaps a bit of dust in a very sensitive system, but after cleaning the devices the alarm persisted. We vented the house.
The next day we worked with the HVAC technicians to trace the exhaust systems from the heater and the hot water heater and found some problems with the exhaust line from the heater; incomplete joining of two pipes, a hole in one pipe, and an incomplete connection at the unit itself. None of these were large but the cottage, designed as guest sleeping quarters, is built to very tight construction standards with minimal fresh air input and the heating system had been running for two months. Much of the exhaust vented as designed through the chimney but some vented directly into the cottage. The gas built up enough to trigger the alarms.
What was at first put aside as a true threat was real. Without the detector’s in place we would never have known there was an issue until something truly terrible happened.
So, go get that CO detector you 
have been thinking about. Install it and test it monthly. If it signals an alarm take it seriously and have your HVAC contractor work with you to find the source of the problem. You and your family will breathe easier.
