How To Avoid Carbon Monoxide In Your Home

As I walked into my 66° home, I immediately adjusted the thermostat warm enough to knock off a few layers of sweaters and shirts. I was home, safe and – soon enough – cozy. As I sat, I knew that other home owners are doing the same thing across the state, but at what cost?

Many people are aware that their combustion furnace can be hazardous due to explosions and fires, but when it’s actually when everything is working as it should that it’s at its most dangerous! Carbon monoxide (CO) is a deadly poison that’s created whenever combustion occurs and is dangerous in large amounts.

So a gas stove? Produces CO. Fireplace? Produces CO. Generators? Produce CO. Propane, oil, gas heaters? All produce CO. Many cases of family deaths and hospitalizations are attributed to CO poison because poisoning happens while everything is seemingly working fine. Read on for tips to protect your family, and how to defend against the odorless, colorless poison present in many homes across the country.

What is carbon monoxide?

The CDC describes carbon monoxide as: “an odorless, colorless gas, which can cause sudden illness and death, is produced any time a fossil fuel is burned.” 

Carbon monoxide is present in campfire, cigarette smoke, and automotive exhaust, so how bad is it? Exposure to different doses for different lengths of time determines the outcome of an individual case, as well as health factors and other conditions.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) defines these exposure lengths and concentrations:

You can see how complaints of headaches indicate how fast-acting and potent carbon monoxide poisoning is. The dangers of furnace carbon monoxide poisoning are compounded at home: as I sit and wait for my space to reach a cozy 72°, the effects of CO poison can cause drowsiness and fatigue, making evening relaxation easier — but potentially fatal. 

Where is carbon monoxide found in homes?

Every time your furnace is heating, it’s producing carbon monoxide as a byproduct of combustion. Engineers and manufacturers understand this, and have transitioned from passively relying on gravity and air density to remove this poisonous gas to actively using fan motors to push it out of the home. 

Some older houses may still utilize natural draft venting so these homes need to be “breathable”. Natural draft venting is a method of flue gas removal that older furnaces used. It’s basically like a chimney. No fan is used, and the heat and natural draft of air into the fireplace allows combustion byproduct to leave the space through the chimney instead of flooding the house with smoke and CO (in a chimney’s case). A breathable home allows more outside air to penetrate the house envelope. It’s an older method of residential construction that has been shown to result in efficiency losses in heating and cooling. 

Conventional homes use newer model furnaces, which allow the home to be protected from outside conditions while still venting carbon monoxide. That means newer furnaces are safe right? Not exactly. 

Over time, every furnace in use has a weak point: it can damage the heat exchanger, which is an essential component of every forced-air heat system. The heat exchanger is a large metal enclosure that absorbs the heat from combustion, then air is blown across it to provide heat into your home.

Through heating seasons and cycles, this metal expands and contracts hundreds of times over its lifespan. This contraction and expansion (along with many other contributing factors) eventually culminates as a crack in the heat exchanger. Once a crack appears, the poisonous gas that was previously contained inside the heat exchanger will begin to leak into the air that is heating your home. 

This may be a small amount at first, 0-20ppm, resulting in benign symptoms. However, through each subsequent cycle of expansion and contraction, the crack will grow, and the leak will allow higher concentrations of carbon monoxide into the house. This phenomenon routinely causes deaths and hospitalizations in households across America, but is becoming increasingly preventable. 

How can I protect myself from carbon monoxide poisoning?

Many HVAC companies offer maintenance contracts that vary in service type, offerings, perks, and costs. It can be overwhelming trying to make a decision! Some homeowners may not find value in such a service and others may simply want filter changes or have other more specific concerns. If you’re heating with combustion, it is of tremendous value to have a maintenance contract with an HVAC company that routinely checks for carbon monoxide and has the equipment and training to do so. A great tip is to get a carbon monoxide check at least once per heating season from an HVAC contractor you trust.

Outside of a cracked heat exchanger, other complications can lead to home carbon monoxide poisoning. For example, a bird’s nest in a chimney’s vent pipe, a clothes dryer, or any other combustion appliance can be just as damaging. These are aspects of the home where some traditional heating and cooling contractors may not provide service. 

In these situations, carbon monoxide detectors are your first alert to danger. Every home, no matter the heating source, can benefit from this extra layer of protection. When a carbon monoxide detector senses CO in the air, it sounds an audible alarm, usually coupled with a visual effect like flashing lights. 

With numerous options on the market, it can be tough to figure out which is best for you. There are plug-in sensors and ceiling/wall mounted sensors, as well as whole home systems integrated with fire and smoke detection. 

When choosing a carbon monoxide detector, two factors come into play: the threshold and location of the unit you select. Some carbon monoxide detectors only alarm at higher concentrations of CO (75 PPM). In contrast, there are models that are more sensitive to lower concentrations (35 PPM or less). Be certain to understand this, as serious health problems occur at higher concentrations. 

As for where to place your carbon monoxide detector, it’s complicated. On one hand, placing your detector too low won’t work, because it’s unlikely to  find carbon monoxide accumulating on the ground. CO is slightly lighter than ambient air and mixes well, so the lower plugins in the home won’t protect as well as a higher receptacle. On the other hand, placing your detector too high may also be a problem. Dust, moisture, exposure to airstream, and sunlight may also affect the location that each type of device will perform best in. Refer to manufacturer instructions to further identify the best setup and type to protect your areas.

If your detector goes off, call a certified professional ASAP! We have sniff out carbon monoxide even in a high concentration area, as well as other mitigation tools. 

What’s the alternative to combustion-based heating systems?

The easiest way to eliminate the risk of carbon monoxide poisoning is to get rid of the source — your combustion furnace. Geothermal heating and cooling uses the ground’s constant energy to heat and cool without burning anything — no gas, no fuel, no fire. No combustion means no carbon monoxide produced. 

Geothermal can also save you money, increase your home’s value, and significantly lower your carbon emissions. Not sure if geothermal is right for you? It might not be. 

Click the button below to get a free consultation and make an informed choice for your family. 

About the author: A proud Dandelion service tech, Josh Atkinson is a family father of three, and has been in the HVAC industry for 8 years. Currently a licensed master HVAC mechanic, residential home inspector, and certified power plant operator.