Large lab building – Variable Air Volume (VAV) Fume Cupboard Upgrade

September 2nd 2026

Project Overview

This large lab implemented a Variable Air Volume (VAV) control strategy on nine constant air volume laboratory fume cupboards.  The objective was to reduce conditioned air extraction when fume cupboard sashes were closed, thereby lowering both ventilation and heating energy consumption while maintaining laboratory safety standards.

Challenge

Traditional constant volume fume cupboards extract the same volume of air regardless of sash position. This results in significant energy waste because conditioned air must be continuously heated, cooled, supplied and exhausted.

Solution

Nine fume cupboards were upgraded to VAV controls that automatically reduce exhaust airflow when the sash is closed.

Airflow Reduction Achieved

The system was designed on the assumption that cupboard sashes remain closed approximately 95% of the time.

Results

Ventilation Savings

The upgrade reduced average exhaust airflow by approximately:

• 1.91 m³/s average annual airflow reduction
• Around 80% reduction in extracted air volume when sashes are closed

Heating Energy Savings

The reduced ventilation load translated into substantial heating energy savings.

Key contributors included:

• Reduced conditioned air extraction
• Lower replacement air heating demand
• Reduced plant operating power

Business Benefits

• Significant reduction in HVAC energy demand
• Lower carbon emissions
• Improved sustainability performance
• Enhanced laboratory operational efficiency
• Rapid return on investment through energy savings

Key Takeaway

Implementing VAV controls on laboratory fume cupboards demonstrated that a controls upgrade can reduce exhaust airflow by approximately 80%, resulting in substantial ongoing heating and ventilation energy savings while maintaining safe laboratory operation.