What is an additional cost associated with using outside air in mechanical ventilation systems?

Using outside air in mechanical ventilation systems brings several additional costs, among which is the necessity of heating and cooling the outside air. When outside air is introduced into a space, it typically does not match the indoor temperature. This discrepancy necessitates the use of additional energy to condition the air to an acceptable level for occupant comfort.

In colder climates, incoming air will often be too cold, requiring heating before it can be supplied into the living or working area. Similarly, in warmer climates, the external air may need to be cooled to prevent excessive indoor temperatures. This process involves energy consumption, which translates into increased operational costs for the system.

Other aspects such as maintenance of fans and air filter replacements are ongoing expenses related to the system but are not unique to the use of outside air. Installation of extra ducts may be relevant in some scenarios to accommodate additional airflow, but the direct cost of conditioning outside air is a predominant and ongoing concern that directly impacts energy consumption and operational budgeting. Thus, the primary additional cost associated with using outside air in mechanical ventilation systems is indeed related to heating and cooling that air to meet indoor environmental quality standards.