It's proved to be an expensive week so far with visits from the electricians to complete some work and the HVAC people to clean our gas furnace. But it could have been much, much worse.
A regular cleaning by the furnace people showed that the heat exchanger in our furnace was majorly cracked. A crack that has proably been growing for months. (Could have been longer since we never had our furnace checked last fall.) When there is a crack in this component, carbon monoxide is produced from the air that is blown over the hot metal (to create your heat) and is pumped out along with the hot air.
As you know, carbon monoxide is a very dangerous gas. According to the Journal of the American Medical Association (JAMA), carbon monoxide is the number one cause of poisoning deaths in the U.S.A. Making sure furnaces and other potential carbon monoxide sources are properly vented and in good working condition, along with owning a carbon monoxide detector, could become a matter of life and death.
We'd been unknowingly living with a danger for some time. Sadly enough, we have a CO detector but just never got around to installing it. I really beat myself up on Monday upon realizing this. Things could have been so much worse; we certainly have the good Lord looking out for us! The price of the new furnace (ouch) is nothing compared to what could have been lost.
So please use my bad experience as a learning opportunity - go out and buy a CO detector. You can get models that just plug into the walls and have battery back-up for about $25. See
here. You can also get units that mount to the ceiling like your smoke detector for about the same price, and that may be better for detection.

Proper placement of a carbon monoxide (CO) detector is important. If you are installing only one carbon monoxide detector, the Consumer Product Safety Commission (CPSC) recommends it be located near the sleeping area, where it can wake you if you are asleep. Additional detectors on every level and in every bedroom of a home provides extra protection against carbon monoxide poisoning.
Homeowners should remember not to install carbon monoxide detectors directly above or beside fuel-burning appliances, as appliances may emit a small amount of carbon monoxide upon start-up. A detector should not be placed within fifteen feet of heating or cooking appliances or in or near very humid areas such as bathrooms.
When considering where to place a carbon monoxide detector, keep in mind that although carbon monoxide is roughly the same weight as air (carbon monoxide's specific gravity is 0.9657, as stated by the EPA; the National Resource Council lists the specific gravity of air as one), it may be contained in warm air coming from combustion appliances such as home heating equipment. If this is the case, carbon monoxide will rise with the warmer air.
For this reason, the makers of First Alert®, a leading brand in carbon monoxide detector technology, suggests mounting the detector on the ceiling. This also puts the detector out of the way of potential interference, such as pets or curious children.
You can read more about this
here.
If you already have a CO detector installed, please test it. This weekend we roll back the clocks and you should use this opportunity to test your smoke alarms and CO detectors. I know that we'll be installing ours immediately.