Why Does My Air Conditioning Unit Increase CO2 Levels?

increased levels of CO2 from air conditioning

Chart showing increased levels of CO2 from air conditioning unit.  How does this happen?  Can anyone explain why a newly installed air conditioning unit would increase CO2 levels in my home?

Here is a chart produced by Foobot that measures indoor air quality factors.  It shows a rapid increase in CO2 when the air conditioning unit is turned on and then a decrease when it is turned off.   Please answer or respond via email. 

An air conditioning unit, particularly a central air conditioning system, does not directly increase carbon dioxide (CO2) levels in the air. Air conditioners work by removing heat from the indoor air and transferring it outside, which helps cool down the indoor environment. The cooling process itself does not produce or release CO2.

However, there are a few indirect factors that can contribute to increased CO2 levels in a building or indoor space when an air conditioning unit is used:

Lack of ventilation: Air conditioning systems often work in conjunction with ventilation systems. If the ventilation system is inadequate or not properly maintained, it can result in poor indoor air circulation and reduced fresh air intake. This can lead to a buildup of CO2, as humans exhale CO2 as a byproduct of respiration.

Infiltration of outdoor air: When an air conditioning unit is running, it typically operates in a closed-loop system, recirculating indoor air. If there are air leaks or poor insulation in the building envelope, outdoor air can enter, bringing with it higher levels of CO2. This is more likely in older or poorly sealed buildings.

Occupant behavior: In some cases, when an air conditioning system is running, people tend to keep windows and doors closed to maintain the desired indoor temperature. If there are many occupants in a confined space, their collective exhalation of CO2 can accumulate, especially if there is insufficient fresh air exchange.

It's worth noting that high CO2 levels indoors can result in poor air quality and discomfort. To mitigate this, it's important to ensure proper ventilation, maintain a well-sealed building envelope, and consider using energy-efficient air conditioning systems that have built-in ventilation features or integrating standalone ventilation systems to enhance fresh air exchange. Regular maintenance and cleaning of HVAC systems are also crucial to ensure optimal performance and air quality.