Indoor Air Quality (IAQ) plays a critical role in safeguarding human health and influencing our well-being, not only representing our direct exposure to commonly known pollutants such as CO2, volatile organic compounds and particulate matter, but also through its role in the spread of airborne pathogens. Humans emit CO2 and airborne pathogens while breathing. The concentration of both in confined spaces can be kept under control minimising the contagious risk thanks to the HVAC system. While temperature control is normally designed in most new and existing buildings, equal importance should be given to controlling IAQ and humidity to help maintain ideal conditions for an effective human immune system. In the context of the urgent need to reduce energy consumption to address climate change, the concept of Zero Energy Buildings (ZEB) is crucial. In the design of such buildings, the primary goal is to achieve high energy efficiency while maintaining high standards of indoor comfort and air quality, within the limits of economic sustainability. Achieving low to zero energy buildings without compromising occupant health and IAQ is a challenge that can be met with HVAC systems that integrate energy recovery, heating & cooling, humidification & dehumidification, intelligent controls and continuous monitoring of operating conditions. This paper presents a complete strategy for ensuring a healthy indoor environment that not only provides a satisfactory return on investment (ROI), but also significantly reduces CO2 emissions, making it a valuable solution in different climatic conditions.