It's cold and now that winter is here you can bet most people's furnace are working a bit harder.
You need to be aware especially this time of year that your furnace can cause carbon monoxide poisoning.
"The most important thing to know about carbon monoxide is you don't know that it's affecting you. It's colorless odorless and tasteless," Julie Davis from the Red Cross said.
So the biggest problem is people don't know they are breathing it. A sign of carbon monoxide poisoning is flu like symptoms like severe headaches nausea, dizziness and sometimes fainting. If you breath it too long it can kill you.
"If your carbon monoxide detector does go off you need to get out of the house," Davis explained.
Once your outside contact the fire department.
Now there are things you can do to keep you safe, like making sure your furnace is working properly no matter how old it is.
"Now of course the older the furnace gets the more of a problem but any furnace can develop a problem, " Davis said.
Also if you are using alternative heat make sure it's in a well ventilated area. But the most importunely have a detector.
"Everyone should have a carbon monoxide detector. It's Christmas time it's a great gift to give someone," Davis said.
Carbon monoxide kills 480 people each year and sends another 15,000 to the hospital.