Carbon Monoxide Safety and Your HVAC System: What Austin Homeowners Need to Know

Why Carbon Monoxide Is a Hidden Winter Danger in Austin Homes

Austin's winters are mild compared to northern states, but Central Texas does experience cold snaps — sometimes dropping into the 20s and 30s overnight. When temperatures plunge, Austin homeowners fire up furnaces that may have sat idle for months. That's when carbon monoxide (CO) risks spike. CO is a colorless, odorless gas produced by the incomplete combustion of natural gas, propane, oil, or wood. At low concentrations it causes headaches and nausea; at high concentrations it can be fatal within minutes.

Unlike northern states where furnaces run constantly and problems surface quickly, Austin's heating systems often go untested for six or more months. Cracks, corrosion, and blockages that developed over the summer can go unnoticed until the first cold night of the year — exactly when you need your heater most. This makes pre-season furnace inspections especially critical for Austin homeowners.

How Your HVAC System Can Produce Carbon Monoxide

The most common HVAC-related source of CO in Austin homes is a cracked heat exchanger. The heat exchanger is the metal component inside your furnace that separates combustion gases from the air circulated through your home. When it cracks — due to age, thermal stress, or overheating from a clogged filter — combustion byproducts including CO can leak directly into your ductwork and living spaces.

Other HVAC-related CO sources include blocked flue pipes or vents (which prevent exhaust gases from escaping outside), improperly sized or installed furnaces that run inefficiently, and gas furnaces with dirty or malfunctioning burners. Even a bird's nest or debris blocking an exterior vent cap can cause dangerous CO buildup inside your home.

It's worth noting that heat pumps — which run on electricity and don't burn fuel — do not produce CO. If you've recently switched from a gas furnace to a heat pump, your CO risk from your HVAC system is essentially eliminated. However, gas water heaters, stoves, fireplaces, and attached garages still pose risks.

Warning Signs of a CO Problem in Your Home

Because CO is invisible and odorless, you can't detect it without a detector. However, there are indirect warning signs that your HVAC system may be producing CO. Watch for: a yellow or orange furnace burner flame instead of a crisp blue flame, excessive condensation on windows when the furnace runs, soot or black marks around the furnace or vents, and a furnace that frequently shuts off on its own (a safety mechanism triggered by overheating).

Physical symptoms are another warning sign. If multiple family members — or pets — experience unexplained headaches, dizziness, nausea, or fatigue that improve when you leave the house, CO poisoning should be suspected immediately. Leave the home, get fresh air, and call 911 before re-entering.

• Yellow or orange burner flame (should be blue)
• Soot or black marks near furnace or vents
• Furnace frequently cycling off unexpectedly
• Unexplained headaches or nausea in household members
• Excessive window condensation when heat is running

CO Detector Placement and Maintenance for Austin Homes

Texas law requires CO detectors in new residential construction, and for good reason. Every Austin home with a gas furnace, gas water heater, gas stove, fireplace, or attached garage should have CO detectors installed. Place detectors on every level of your home, including the basement if you have one, and within 10 feet of each sleeping area. CO is slightly lighter than air, so mid-wall placement (about 5 feet high) is generally recommended, though ceiling placement also works.

Test your CO detectors monthly using the test button, and replace batteries annually — a good habit is to swap them when you change your clocks for daylight saving time. CO detectors have a lifespan of 5–7 years; check the manufacture date on the back and replace any unit that's past its expiration. Don't rely on smoke detectors alone — most smoke detectors do not detect CO.

The Importance of Annual Furnace Inspections in Austin

The single most effective way to prevent CO exposure from your HVAC system is a professional furnace inspection before each heating season. A licensed HVAC technician will inspect the heat exchanger for cracks, check burner operation and flame color, test the flue and venting system for blockages, verify that safety controls are functioning, and measure combustion efficiency. These checks can catch dangerous defects before they become life-threatening emergencies.

Austin's climate means furnaces often sit unused from April through October. Six months of inactivity can allow dust buildup on burners, pest intrusion in vents, and corrosion in older units. A pre-season tune-up — ideally in October or early November before the first cold snap — ensures your system is safe and efficient when you need it most. Austin Air Pros offers comprehensive heating system inspections for Austin and surrounding Central Texas communities. Call us at (512) 580-8055 to schedule your pre-season furnace check today.

If your furnace is more than 15–20 years old, the risk of heat exchanger failure increases significantly. An aging furnace with a cracked heat exchanger should be replaced, not patched — the safety risk is too great. Our team can help you evaluate whether repair or replacement makes more sense for your home and budget.

What to Do If Your CO Detector Goes Off

If your CO detector alarm sounds, treat it as a life-safety emergency — not a nuisance alarm. Immediately move everyone (including pets) outside to fresh air. Do not stop to gather belongings. Once outside, call 911. Do not re-enter the home until emergency responders have cleared it and identified the source.

After the emergency is resolved, call a licensed HVAC technician to inspect your heating system before using it again. Austin Air Pros provides emergency heating repair services throughout the Austin metro area. Our technicians are trained to identify and repair CO-related HVAC defects, including cracked heat exchangers, blocked flues, and faulty burners. Don't take chances with carbon monoxide — call (512) 580-8055 for prompt, professional service.