Ventilation strategies in net-zero energy buildings: Balancing indoor air quality and energy efficiency

This review paper examines ventilation strategies in Net-Zero Energy Buildings (NZEBs), with particular focus on balancing indoor air quality (IAQ) and building energy usage. The central question addressed is how ventilation systems can be optimized to meet sustainability goals while maintaining acceptable IAQ with minimal energy use. Reported findings show that heat recovery ventilators reduce HVAC energy by 13.5–19.7% in cold climates, while earth-to-air heat exchangers significantly lower summer demand in Mediterranean regions. Natural ventilation combined with passive design strategies achieve energy savings of up to 62% in educational buildings, and adaptive electrochromic systems yield annual savings of up to 26.6%. Conversely, mechanical ventilation has been shown to increase energy use by about 20% in some cases, underscoring the need for climate- and context-specific solutions. This review paper synthesizes mechanical, natural, hybrid, and smart ventilation performance in a climate-sensitive way, explicitly addressing trade-offs between energy efficiency and IAQ, the role of occupant behavior, and the long-term viability of different approaches when evaluated in an NZEB setting. The findings suggest that hybrid ventilation systems, powered by renewable energy and managed by intelligent controls, are among the most promising pathways toward NZEB targets. However, challenges related to climate variability and occupant behavior remain critical. The insights presented serve as a guideline for developing effective and sustainable ventilation solutions in NZEBs.