Balanced mechanical ventilation simultaneously supplies filtered fresh air and exhausts stale air in equal volumes, maintaining neutral building pressure. This approach combines the benefits of both supply and exhaust ventilation while avoiding pressure imbalances. Equal airflow rates (typically 0.35 ACH per ASHRAE 62.2) prevent moisture accumulation and infiltration problems.
Technical Specifications
Balanced systems use dual fans or a single unit with separate supply and exhaust pathways. Supply air is filtered through MERV 8-13 filters before distribution. Operating costs are moderate, with two fans consuming 300-600 watts depending on home size and ductwork design. Proper ductwork sizing and sealing maintain system balance within 10% variance between supply and exhaust airflows.
Applications and Benefits
Balanced ventilation suits most climates and building types, particularly new construction with tight envelopes. It provides consistent indoor air quality without pressure-related issues like backdrafting or excessive infiltration. However, balanced systems lack heat or energy recovery capability, making them less efficient in extreme climates compared to ERV or HRV systems. They work well in moderate climates where heating and cooling loads are manageable without recovery equipment.