Texas

Believe it or not, the weather is about to get cooler. That means turning off the air conditioner at home and turning on the heater.

That also means making sure the home's heat-producing appliances run the way they are supposed to, said an expert from Texas Cooperative Extension.

Having the heating system checked before winter starts could prevent a tragedy--carbon monoxide poisoning, said Janie Harris, Extension housing and environment specialist.

"Carbon monoxide is an odorless, colorless gas that interferes with the delivery of oxygen in the blood to the rest of the body," she said. "Even though carbon monoxide will not explode, it can be dangerous--even deadly--to you and your family."

Symptoms of carbon monoxide poisoning include headache, nausea and disorientation, Harris said.

This dangerous gas can be produced inside a home if carbon-containing fuels are incompletely burned, she said.

"The gas must be exhausted to the outside," she said.

These fuels include natural gas, coal, wood, fuel oil and charcoal--the sources used most often in home heating.

The culprits include oil or gas furnaces and cooking appliances, water heaters, fireplaces and wood stoves that aren't working or vented properly, Harris said.

"Two common sources of carbon monoxide in homes in Texas are the gas furnace heat exchanger and the gas hot water heater," she said. "As homes have been built to be more energy-efficient, they have fewer places where fresh air can leak into the home. In order for fuel-burning equipment to operate correctly and safely, it must have a source of fresh air for complete combustion. The ventilation system should provide the fresh air."

A negative pressure could be created inside the house, causing these gases to be pulled back inside in a process called backdrafting, Harris said.

Other sources of carbon monoxide are unvented kerosene and gas space heaters, fireplaces, gas or wood stoves, automobile exhaust from attached garages and tobacco smoke, she said.

To protect home and family from the dangers of carbon monoxide this winter, Harris suggested the following steps:

--Have the home furnace checked by a professional who will make sure the burners and vent systems are working correctly and the heat exchanger isn't cracked.

--Look at the area around the furnace to make sure enough fresh air can flow in. A home's furnace should not be in a tightly enclosed space.

--Make sure the water heater and the furnace flue have no internal obstructions or leaks near the joints.

- To test a gas water heater while the burner is on, hold a lighted match under the draft hood. The flame should burn upward. If the match flickers downward or goes out, the exhaust may have a back flow and is releasing carbon monoxide into the house.

--Open the damper of a fireplace or wood stove so combustion gases will flow outside.

--Never use a gas range to heat the house.

--Don't leave cars or lawn mowers running in an attached garage. Carbon monoxide given off by these vehicles can drift into the house.

--Make sure all combustion equipment and appliances in a home are installed correctly, are properly maintained and have adequate ventilation.

--Don't use all of the home's exhaust vents and the clothes dryer at the same time. This could create negative pressure in the house, pulling carbon monoxide back inside.

"If you have the fireplace burning and turn on the kitchen exhaust vent, you will likely smell smoke," Harris said. "This means the fireplace is not drawing the carbon dioxide out, but is backdrafting. If you use only one of the exhaust fans--bathroom, kitchen or dryer--the backdrafting will not likely occur."

--Use carbon monoxide detectors near sleeping areas and fuel-burning appliances. Choose detectors that have Consumer Product Safety Commission and Underwriters Laboratories seals of approval.

--If a carbon monoxide detector goes off, call the fire department immediately and get everyone out of the house. Anyone with symptoms of carbon monoxide poisoning should be taken to an emergency room.

For more information about this and other home environment issues, visit Extension's Family and Consumer Sciences website at http://fcs.tamu.edu/ and click on the link to "House and Home."