What is the main effect of an increase in indoor humidity on an HVAC system?

An increase in indoor humidity primarily leads to reduced cooling effectiveness in an HVAC system. When humidity levels rise, the moisture content in the air makes it feel warmer than it actually is, due to the body’s natural cooling process through perspiration becoming less effective. This can overwhelm the cooling system, as it has to work harder to remove excess moisture from the air along with lowering the temperature.

In humid conditions, the air conditioning system may struggle to reach set temperatures, and occupants might feel uncomfortable even with the system running. This is because the HVAC system's cooling effectiveness is diminished when it has to manage both temperature and humidity, leading to higher energy consumption and potential strain on the equipment.

The options indicating increased energy efficiency, increased equipment lifespan, and improved indoor air quality do not align with the impact of high indoor humidity. Instead, the increase in humidity generally necessitates more energy for dehumidification and can lead to stress on equipment, potentially shortening its lifespan and negatively affecting air quality if moisture levels promote mold and mildew growth.