The ENERVEX Retrofit Modulating Building Exhaust System™ (MBESr) is a demand-controlled ventilation system designed for multi-story buildings with multiple kitchen hoods, bathrooms or clothes dryers on multiple floors specifically geared toward retrofit applications.
Rather than having a large number of individual exhaust ducts for each appliance, or a fan that operates at full speed 24/7, the MBESr senses when appliances are running and modulates with the load. It assures proper exhaust rates at any time no matter the demand. They MBESr system can reduce the exhaust rate of conditioned air by up to 60-70%. In addition the BEFx fan is ultraefficient with high-efficiency housing design and a IE5 highly efficient EC-motor.
Traditional exhaust systems run at full speed all day—regardless of actual demand. That means you’re exhausting conditioned air and consuming energy even when appliances aren’t running.
The MBESr replaces that constant-speed approach with demand-controlled ventilation built directly into the fan system.
Instead of guessing airflow needs, the system continuously monitors pressure inside the duct and automatically adjusts fan speed in real time:
This creates a self-regulating exhaust system that matches ventilation to actual usage, without manual intervention or external control panels.
Because controls are integrated into the unit, installation is simplified and commissioning is faster compared to traditional fan + VFD + external control setups.
Engineered for:
Construction Suitable for:
Reduce Energy Waste by Matching Demand
Eliminate unnecessary fan runtime and conditioned air loss by only ventilating when needed, often reducing energy consumption dramatically compared to constant-speed systems.
Retrofit Without Re-Engineering
Upgrade existing systems without major duct or system redesign, making it easier to modernize older buildings and aging infrastructure.
Lower Operating Costs
Reduce both:
Simplify Installation and Commissioning Integrated controls remove the need for multiple components (fan + VFD + external controller), reducing wiring, setup time, and potential points of failure.
Improve Tenant Comfort Lower noise levels and more stable airflow help reduce common complaints associated with constant-speed exhaust systems.
Reduce Maintenance Burden
Service-friendly design and controlled operation reduce wear on components and simplify ongoing maintenance.
Support Sustainability and Compliance Goals
Helps buildings meet energy efficiency targets and evolving code requirements while reducing overall environmental impact.
Multi-use, high performing, variable-volume centrifugal exhaust box fan designed for indoor and outdoor installation. Can be used for special exhaust or exhaust of lint-laden air or to supply make-up air and combustion air.
A modulating pressure control that provides superior pressure control in single- or multi-story building applications such as clothes dryers, bathrooms and kitchens.