The short answer is absolutely. A furnace produces heat for your home or office by burning natural gas or propane and one of the by-products of burning fossil fuels is carbon monoxide. Carbon monoxide is often called the “silent killer” since people will breathe it in without seeing, tasting or smelling it. It is toxic in high concentrations.
According to the CDC, more than 400 Americans die each year from accidental carbon monoxide poisoning.
In a properly operating furnace the burned fuel, including carbon monoxide, travels safely outside through the flue pipe. With a fireplace or a wood stove the wood burning puts off smoke and carbon monoxide and these normally exit the home through the chimney or stove pipe. If you had a problem with the fireplace where carbon monoxide was getting into the room, then you would also see the smoke from the fire and naturally take some action. But in furnace, since the combustion of fuel is so efficient, there is no smoke and so if you have a leak you will not be able to see it.
So for “safety first” TRS A/C Services and Construction, Inc. recommends that the furnace safeties be tested and test for carbon monoxide every winter. When we test for carbon monoxide we use specialized equipment to verify that the furnace is operating safely and that no carbon monoxide is leaking into the home.
If your furnace is blowing carbon monoxide into your home, this indicates that the heat exchanger is cracked and is in need of replacement.