Why Carbon Dioxide Can Be Dangerous in a Home

Carbon dioxide (CO₂) is a colorless, odorless gas that we naturally exhale every time we breathe. Outdoors, it’s not usually a concern because it disperses into the open air. Indoors, however, CO₂ can build up to levels that make the air unhealthy to breathe—especially in homes that are tightly sealed or poorly ventilated.

As part of a complete home inspection, checking for ventilation issues that contribute to poor indoor air quality is an important step in protecting both health and comfort.

Why Too Much CO₂ Is a Problem

• Reduces Oxygen Levels
  When CO₂ levels climb, the air contains less available oxygen. This can leave you feeling tired, groggy, or out of breath.
• Affects Health and Comfort
  Even moderate levels of CO₂ indoors can cause headaches, dizziness, poor sleep, and difficulty concentrating. Very high levels may lead to nausea, confusion, or fainting.
• Signals Poor Indoor Air Quality
  Elevated CO₂ is often a sign that a home’s ventilation isn’t working properly. If CO₂ is high, other pollutants like allergens, chemicals, or mold may also be trapped inside.

How CO₂ Builds Up in a Home

• Poor Ventilation
  Modern homes are often built to be “airtight” for energy efficiency. While this helps lower utility bills, it can also trap stale air inside. Without enough fresh air coming in or old air being vented out, CO₂ from everyday living quickly accumulates.
• Gas Appliances
  Stoves, furnaces, fireplaces, and water heaters that burn natural gas, propane, or oil release CO₂ during combustion. If these appliances aren’t vented properly, or if exhaust fans aren’t used, the gas can remain indoors and raise levels.
• Everyday Living
  Simply having several people in a closed room—such as during a gathering, in a basement, or in a small bedroom—can raise CO₂ levels because everyone is exhaling into the same limited air supply.

CO₂ vs. Carbon Monoxide (CO): Know the Difference

It’s common to confuse these two gases, but they’re very different:

• Carbon Dioxide (CO₂)
  Naturally produced by people and appliances. Dangerous mainly when it builds up indoors due to poor ventilation.
• Carbon Monoxide (CO)
  A highly toxic gas that comes from faulty or incomplete burning of fuels. Even a small amount can be deadly, which is why every home should have carbon monoxide detectors.

Both gases highlight the importance of proper ventilation and appliance maintenance, but carbon monoxide poses a much more immediate and severe risk.

How to Prevent CO₂ Problems in Your Home

• Improve Ventilation
  Open windows regularly, especially in bedrooms and basements, or consider a mechanical ventilation system to circulate fresh air.
• Maintain Appliances
  Have furnaces, stoves, fireplaces, and water heaters inspected and serviced to ensure they are venting properly and safely.
• Use Exhaust Fans
  Run kitchen and bathroom fans when cooking or showering to pull out stale air and bring in fresh air.
• Monitor Air Quality
  Indoor air quality monitors can measure CO₂ levels, giving you a clear picture of how healthy your air is.

The Role of a Home Inspection

A professional home inspection doesn’t just evaluate the visible structure and systems—it also provides insight into hidden concerns like poor ventilation, appliance issues, or other conditions that affect indoor air quality. Identifying these risks before you buy or sell a home helps protect your health, your comfort, and your long-term investment.

Schedule your home inspection with 5D Home Inspections today and ensure your home is safe, healthy, and ready for you to enjoy.