Louise McHugh at Breathing Buildings puts the case for hybrid natural/mechanical ventilation to balance air quality and energy efficiency, to support school learning.
The publication of updated Government guidance in February 2026 has reinforced the importance of ventilation in education settings for healthy and productive learning environments.” The guidance places renewed emphasis on how ventilation should be managed in practice, particularly in balancing ventilation with energy efficiency and thermal comfort.
For architects and building services engineers, this reflects an increasingly complex design challenge. Ventilation must now respond to dynamic internal conditions, fluctuating occupancy and external climate, while also supporting compliance with energy and overheating requirements. The guidance identifies natural, mechanical and combined approaches to ventilation, and highlights the importance of adjusting ventilation rates to suit conditions, maintain comfortable internal temperatures and conserve energy.
This represents a shift towards more responsive, operationally driven design. In school environments where occupancy density is high and internal heat gains vary throughout the day, the ability to modulate ventilation is essential to maintaining acceptable indoor air quality (IAQ) without incurring unnecessary energy penalties.
As school buildings continue to improve in terms of airtightness, reliance on designed ventilation systems has increased. Reduced air infiltration improves energy performance but removes a degree of passive air exchange, making controlled ventilation critical. The guidance reinforces the role of ventilation in removing polluted air and airborne contaminants, while also highlighting its contribution to reducing the spread of respiratory infections. However, increasing ventilation rates, particularly during colder months, can increase heating demands if not carefully managed.
This highlights the challenge of balancing IAQ, thermal comfort, and energy efficiency, particularly in education settings where both operational cost and occupant wellbeing are key considerations.
Hybrid ventilation
Natural ventilation systems rely on facade openings, vents or stacks, with airflow driven by wind, buoyancy and temperature differences. Mechanical ventilation systems provide controlled airflow using fans and ductwork. This allows designers to achieve consistent IAQ and thermal comfort. Combined with heat recovery, these systems can reclaim energy from exhaust air, reducing heating demand.
Hybrid ventilation brings together the strengths of both in one system to optimise IAQ, thermal comfort, and energy efficiency. For commercial buildings with high heat gains, hybrid ventilation makes use of free heat, reducing demand on heating systems and cutting energy bills. Schools can maximise health, comfort and sustainability without having to invest in significant building works, making it ideal for retrofitting.
The addition of a low-resistance heat exchanger cell, providing both heat recycling and heat recovery, can reclaim more heat, providing greater occupant comfort, and allow users to include it within building energy assessments (SBEM).
The guidance also highlights the role of ventilation in preventing overheating and maintaining comfortable internal conditions. This aligns with BB101 (2018) ‘Guidelines on ventilation, thermal comfort and indoor air quality in schools’, which sets limits on temperature and overheating in teaching spaces. Natural ventilation, when carefully designed, can effectively manage internal temperatures in mid-season and summer conditions. Strategies such as appropriate facade design, window sizing, shading and the use of thermal mass can help prevent overheating, while maintaining a low-energy approach.
Meanwhile, with MVHR, features such as summer bypass and night-time cooling allow the systems to respond effectively to warmer temperatures, providing good year-round thermal comfort.
The hybrid approach means ventilation optimises IAQ, comfort and efficiency by automatically switching between natural, hybrid and mechanical ventilation, maximising the benefits.
A key theme within the Government guidance is the importance of monitoring ventilation and air quality. In practice, this requires the integration of sensors and control systems capable of responding to real-time conditions.
CO2 concentration, internal temperature and external conditions can be used to control operation. Ventilation supplied with external temperature sensors, and internal temperature and CO2 sensors, as well as an intelligent controller can adjust ventilation rates dynamically, maintaining IAQ while minimising energy use.
The recent Government guidance reinforces that ventilation is central to both health and education, linking ventilation to pupils’ concentration, comfort and infection control. Achieving the right balance between IAQ, thermal comfort and energy efficiency is essential and requires a coordinated approach, integrating ventilation within the wider building design. And of course, ensuring it operates as designed.
Louise McHugh is product manager at Breathing Buildings