Laboratory HVAC systems are often designed for the worst possible day—but operated under normal conditions more than 99% of the time. That mismatch creates one of the biggest value engineering opportunities in laboratory construction. By using demand-based ventilation strategies, many projects can reduce the size of major HVAC equipment while improving long-term performance.
Why is laboratory HVAC equipment often oversized?
Traditional laboratory ventilation is typically designed around a fixed air change rate (ACH), often between 8 and 10 ACH, determined during the Laboratory Ventilation Risk Assessment (LVRA).
Because this airflow must always be available, engineers size air handlers, chillers, boilers, and exhaust systems for maximum demand—even though those conditions rarely occur.
The result is larger mechanical equipment, higher construction costs, and increased energy consumption throughout the life of the building.
What is the biggest value engineering opportunity in laboratory HVAC?
The greatest opportunity is often reducing the size of primary mechanical equipment rather than making small changes to ductwork or materials.
When ventilation can respond to actual laboratory conditions instead of worst-case assumptions, the mechanical plant no longer needs to support peak airflow everywhere at the same time.
This can reduce the required capacity of:
- Air Handling Units (AHUs)
- Chillers
- Boilers
- High-plume exhaust systems
How does Demand Control Ventilation (DCV) work?
Demand Control Ventilation uses real-time environmental sensors to monitor laboratory air quality.
Instead of continuously supplying 8–10 ACH, the system can:
- Operate at approximately 2 ACH during normal clean conditions.
- Automatically increase ventilation to 12–18 ACH if contaminants are detected.
- Return to normal ventilation once the event has passed.
The laboratory receives more ventilation when needed—and less when it isn't.
Does reducing airflow make laboratories less safe?
No—not when the system is properly designed.
A demand-controlled system actually responds to changing laboratory conditions instead of assuming the worst case is happening all day, every day.
When contamination is detected, airflow increases automatically, providing rapid dilution and removal before returning to normal operation.
How does DCV reduce construction costs?
One of the biggest savings comes from applying system diversity.
Research and operational data show that laboratory contamination events are rare and typically short in duration.
Because not every laboratory will require maximum airflow simultaneously, engineers can calculate a realistic peak demand for the entire building rather than sizing every piece of equipment for full-capacity operation at the same time.
This often allows smaller:
- Air handlers
- Chillers
- Boilers
- Exhaust fans
without compromising laboratory performance.
Doesn't DCV add additional costs?
Yes.
Demand Control Ventilation requires sensors, controls, and additional system integration.
However, these costs are frequently offset by reductions in primary HVAC equipment costs.
For many projects, the savings from smaller mechanical equipment exceed the cost of implementing the control system, creating a positive return before the building is even occupied.
When should Value Engineering be considered?
The best time is before equipment procurement.
If a project is exceeding its mechanical budget, contractors can submit a Value Engineering proposal or Request for Information (RFI) asking the Engineer of Record to evaluate equipment sizing using a demand-controlled ventilation strategy.
Making this adjustment early provides the greatest opportunity to reduce capital costs while preserving long-term building performance.
The Bottom Line
Traditional laboratory HVAC systems are commonly designed around maximum ventilation requirements that occur only occasionally.
By shifting from fixed air change rates to demand-based ventilation, project teams can often reduce the size of primary HVAC equipment, recover construction budgets, and deliver laboratories that are both safer and more energy efficient over their lifetime.