Do Air Conditioners Produce Carbon Monoxide?

When you think about carbon monoxide (CO), your mind probably goes straight to things like gas furnaces, fireplaces, or car exhaust. But what about your air conditioning system? Can it produce carbon monoxide too? It’s a fair question, and you’re not alone in wondering. There’s some confusion because of how CO is associated with heating systems, so let’s break it down and clear up the air.

Understanding Carbon Monoxide and How It’s Produced

Carbon monoxide is a colorless, odorless gas that is created when fuels like gas, oil, or wood don’t burn completely. Most commonly, it’s associated with things like gas furnaces, water heaters, and even appliances like stoves or fireplaces that burn fuel.

It’s a dangerous gas because, since you can’t see or smell it, it can build up in your home and become a serious health hazard without warning. Inhaling high concentrations of CO can lead to symptoms like dizziness, headaches, confusion, nausea, and even life-threatening conditions. According to the Centers for Disease Control and Prevention, about 400 people in the United States die each year from unintentional carbon monoxide poisoning not linked to fires, and an additional 14,000 are hospitalized.

For an HVAC system to produce CO, it must burn fuel. This is where AC systems differ. Air conditioners – whether central units, window units, or portable models – don’t use combustion to operate. They work by moving refrigerant through coils to absorb and release heat, thus cooling the air in your home.

Since they don’t burn any fuel, air conditioners do not produce carbon monoxide. Similarly, heat pumps and electric furnaces also operate without combustion, so they are free from CO emissions. However, gas and oil furnaces; gas, oil, and propane, boilers; and gas water heaters can produce carbon monoxide if they burn fuel improperly or have ventilation issues.

Why People Might Think ACs Could Produce CO

So, why do some people ask – do air conditioners produce carbon monoxide? It likely comes from the fact that people often associate CO with other parts of their home that do burn fuel, like gas furnaces. Many homes have both a furnace and an AC system, and while the furnace might produce CO (if it’s not properly maintained), the AC itself does not.

If you have an old furnace or a furnace that isn’t working properly, it could produce dangerous levels of carbon monoxide due to incomplete combustion, poor ventilation, or a cracked heat exchanger, which can allow CO to leak into your home instead of being safely vented outside. In such cases, it might seem like the entire HVAC system (which includes both heating and cooling) could be responsible for CO, even though the air conditioner part of the system isn’t involved in the combustion process.

How to Keep Your Home Safe from Carbon Monoxide

Even though your air conditioner isn’t a source of carbon monoxide, it’s still important to be proactive about your home’s safety. Here are a few steps you can take:

Install carbon monoxide detectors

Place these detectors on every floor of your home and outside of bedrooms or sleeping areas. When the CO detectors sense dangerous levels of carbon monoxide in the air, they will go off to alert you to the potential hazard, giving you time to evacuate your family and pets and address the issue before it becomes life threatening. A good rule of thumb is to inspect CO detectors monthly and replace the batteries at least once a year.

Get your furnace serviced regularly

An annual inspection by a professional HVAC technician can help identify potential issues with your furnace or other fuel-burning appliances, such as leaks, cracks in the heat exchanger, or improper combustion, before they become serious problems and potentially leak dangerous CO. The best time to perform maintenance is in the fall before the arrival of cold weather.

Ensure proper ventilation

Make sure your furnace, water heater, and stove are vented properly to the outside to prevent carbon monoxide from building up in your home. While you can check vents for blockages or damage yourself, it’s a good idea to have a professional HVAC technician conduct a thorough inspection to make sure your fuel-burning appliances are all working safely and correctly.