CARBON MONOXIDE ALERT!!
The neighbor of a good friend of mine had a big scare this week. They moved into a 1970's house several months ago and soon installed new vinyl windows. This week they used their fireplace one evening while the kids were sleeping upstairs. They had a new carbon monoxide detector and it soon alarmed; in the meantime, they had developed headaches and other symptoms they recognized as carbon monoxide poisoning. They called the fire department, and after the house had been checked out, they were told that the carbon monoxide level had reached over 900 parts per million-enough to cause unconsciousness and death in a couple of hours.
What happened you ask? Apparently the old windows had leaked enough air to satisfy the oxygen requirements of the fireplace. After the new, tight ones were installed, the fireplace stole its air through the furnace flue on the roof and dragged carbon monoxide into the house with it The moral: WHEN USING A WOOD BURNING FIRPELACE, CRACK A WINDOW TO LET FRESH AIR INTO THE HOUSE !!
PS: If you don't already have a carbon monoxide detector, get one ASAP.