Rosenberg's ECFanGrid replaces old belt-driven fans in any air handling unit without major structural changes, cranes, or downtime.
Engineered to solve the real problems of retrofitting—energy waste, installation complexity, downtime risk, and maintenance burden.
EC motors achieve system efficiencies over 70%, cutting energy use by up to 50% versus old belt-driven fans. Fan replacement pays back in two to five years on average.
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Compact components fit through standard doors. No crane and no structural changes. Two people can handle all parts and bring them in via normal stairs and lifts.
No belt drive means no abrasion dust, no second filter stage, and a fully accessible floor inside the AHU. Fans are lubricated for life and directly driven.
Built-in redundancy means if one fan fails, the remaining fans automatically increase speed to compensate—no downtime, no service interruption.
An ECFanGrid replaces a single large belt-driven fan with an array of smaller, electronically commutated (EC) fans operating in parallel. Volume flow scales with the number of fans while pressure remains constant—and the system keeps running even if one fan fails.
Because every retrofit presents different mechanical and spatial constraints, Rosenberg offers ECfan Grid systems in multiple configurations. Each option is engineered to integrate into existing equipment while delivering consistent performance, efficiency, and reliability.
Powered by energy-efficient EC Motors, Rosenberg’s ECFanGrid provides a compact and modular solution for HVAC retrofit and new Air Handling Unit (AHU) installations. Compared to traditional single large blowers, the ECFanGrid system can reduce required space by up to 50%, offering a flexible setup tailored to your specific needs—whether it’s a 1x3, 2x2, 2x3, or 3x3 configuration. Our multi-fan systems ensure uniform airflow distribution, enhancing the performance of downstream components like coils and filters. Additionally, using multiple fans instead of a single blower produces higher-frequency sound levels, allowing for smaller attenuators and more efficient airflow management.
Rosenberg's ECFanGrid Retrofit Kit is the ideal solution for upgrading your HVAC system. This all-in-one kit provides everything necessary for a smooth and efficient retrofit, improving system performance, and energy savings. Simply provide us with your Airflow, Static Pressure, and Cabinet dimensions, and our team will customize the perfect kit for your needs.
The ECFanGrid Retrofit Kit includes:
The Unobox is a self-contained EC fan system featuring a backward-curved impeller mounted inside a durable and insulated box. Designed by Rosenberg for modular HVAC systems, the Unobox is ideal as a stand-alone unit or when replacing outdated casings. Its robust extruded aluminum frame is complemented by thermally and sound-insulated galvanized steel panels, ensuring efficient performance and quiet operation. Powered by Rosenberg’s energy-efficient and easy-to-control EC motors (ECM), the Unobox can be stacked in any configuration, offering flexible solutions for your HVAC needs.
Simple, reliable, and ready to use – Plug and Play.
Multiple provincial incentive programs for the installation of VFD’s delivered by local hydro companies are available for retrofitting commercial, industrial, and residential HVAC systems. Rosenberg EC fans comply with these retrofit incentives in different ways:
Our ECFanGrid is a multiple fan array that was designed for HVAC Retrofit. Unlike "FanWall" systems by Nortek, who buy AC motors from another company, we build and use our own EC motors. Rosenberg's EC motor (ECM) technology is more compact than AC motors, and our built-in speed controls are more energy-efficient than VFDs used with AC motors. Our speed controls are fully variable from stopped to full-speed and save more energy as the speed is reduced. VFDs only operate down to 50% of full-speed and become less energy-efficient as they reduce the AC motor’s speed. Our EC motors power our ECFanGrid to make it the most compact, energy-efficient, and truly 100% variable-speed, multiple-fan system available on the market today.
Our goal is to provide our customers with all the tools needed for a successful HVAC retrofit project. With our Rosenberg Retrofit Kit, we deliver all the elements to fit the ECFanGrid inside the plenum of any existing Air Handler (AHU).
Consider Rosenberg’s ECFanGrid for your next HVAC Retrofit project.
To find out more information on energy rebates and incentives OFFERED by the government of canada, choose a province:
Saving on energy with Rosenberg Fan Energy-efficient Retrofit Kit
Rosenberg's Retrofit Kit includes all components needed that contemplates all the elements needed when thinking on retrofitting old coupled through belts or other inefficient types of fans to outdated non-premium motors.
We have the only solution that allows efficient external rotor EC motors fans (ECM) to be mounted directly to the plenum.
Download Brochure for more details about Rosenberg Retrofit Kit.
Watch Assemblage Video.
Real results from real retrofits—energy savings, improved reliability, and lower maintenance across commercial and industrial facilities.
The project focused on upgrading two identical, outdated, and inefficient Air Handling Units with Rosenberg's state-of-the-art ECFanGrid.
The previous Air Handling Units had become obsolete, leading to suboptimal performance and increased energy consumption.
Recognizing the need for a more sustainable and cost-effective solution, the decision was made to install Rosenberg's ECFanGrid to modernize the building's ventilation system.
The installation of Rosenberg's ECFanGrid brought substantial benefits to the Administrative Building in Ottawa. With fan redundancy ensuring uninterrupted operations and substantial energy savings, the retrofit project improved energy efficiency and indoor comfort.
The successful implementation demonstrates the building's commitment to sustainable solutions, setting an example for others to embrace greener practices and reduce operational costs.
Supply Fan 1: 50,000 cfm @ 5.25” SP
Supply Fan 2: 50,000 cfm @ 4.75” SP
Providence Health/Brock Fahrni sought solutions to avoid wall demolition due to limited access and to upgrade their outdated fan system. Previously, any failure of the fan caused the entire system to stop, leading to an interruption of airflow.
The installation of the ECFanGrid provided fan redundancy, ensuring uninterrupted operations. Other significant benefits of this retrofit project for the building included energy savings, space optimization, and improved energy flow.
Replace the old belt-driven fan (rated 125 HP motor operating at 50,000 CFM @ 1.5” of total static pressure). The ball bearings in the motor had been replaced four times in the past five years causing significant downtime and at a total cost of $40,000.
Rosenberg Fans Canada’s retrofit solution uses our 3x3 ECFanGrid.Our system’s total power is only 42 HP to produce 50,000 CFM @ 1.5” of total static pressure. That is one third of the original motor’s 125 HP, which will translate into significant power and electricity cost savings. No maintenance is required for EC fans, and the system can be running when a fan needs to be replaced. There should be no system downtime, ever. ECFanGrid control has been seamlessly integrated into the existing building management control system.
An old belt-driven 10-HP fan has been replaced by two of Rosenberg's quiet and energy-efficient EC (ECM) fans.
A 2x1 ECFanGrid is supplying 9,375 CFM at 2.2" of total static pressure with a total input power of 7.6 HP. Our very efficient composite "E”-wheel impellers were used in this project. The speed is controlled with a simple potentiometer provisionally. The final upgrade will include automation and communication with the building management system using the analog and digital communication ports that are integrated into each of Rosenberg’s EC fans.
Design and installation of the ventilation and air conditioning system in a brand-new, multi-use arena located in the city of Edmundston, New Brunswick. The new amphitheater is a $21-million project and will have a total capacity of 2,400 seats for ice sports, and 3,680 seats for show configuration.
The customer was looking for an efficient system not dependent on just one fan. Another important feature was to minimize the footprint of the new Air Handling Unit, maximizing the available real estate. Rosenberg’s ECFanGrid was the perfect solution.
Increasing reliability, redundancy, and capacity in an existing air handling unit. Three compact, light, and reliable Rosenberg’s Unoboxes, each equipped with our external rotor motor plug fans, were selected for retrofitting two outdated forward-inclined curved blowers driven by a single shaft coupled to a single motor.
Our Unoboxes were a perfect fit to the existing casing. Due to their compact and light design, it was possible to accommodate three fan assemblies, each with an independent AC motor providing increased capacity and efficiency to a system that was totally dependent and prone to failure. The use of three Rosenberg Unoboxes provided the system with built-in redundancy, avoiding the total shut down of the system in the event of failure.
Rosenberg’s UNOBOX powered by EC Motor plug fan was the selected choice when increasing flow rate on this facility. The UNOBOX ready-to-use casing and simple design was installed at the discharge of the supply fan to achieve the desired flow rate in an easy and simple way—PLUG & PLAY.
The Flexibility of Rosenberg’s multiple size Unobox ready-to-stack casings, in combination with the different diameter of fans and motor sizes, give multiple options to the property management, contractor, or engineer to solve any given retrofit or upgrade project. Increased flow rate, increased static pressure, reduction of operational costs, ease of control and configuration are what the EC FAN GRID, RETROFIT KIT, UNOBOX, or standard GKHM original design can provide for your next ventilation project.
Rosenberg Fans Canada was awarded a multi-facility contract to retrofit old fans with our EC FAN GRID concept. The following is an illustration of the work done and the advantages of our multiple-fan approach.
The EC FAN GRID array was installed and commissioned while the old belt driven fan was still operational. With this upgrade, our customer’s risk of being dependent on just one fan for continuous operation was eliminated.The 4x2 grid has space for future expansion as only seven fans were installed. The flexibility for future demand is already included in the solution without the need of major modifications. The efficient EC FAN GRID motors allow operational savings right away of more than $8,000. The available air flow rate is 20% higher; there is less space used, less weight, less sound, and less vibration.
Rosenberg Fans Canada was awarded a multi-facility contract to retrofit old fans with our EC FAN GRID concept. The following is a summary of the work done and the advantages of our multiple-fan approach.
This project was completed quickly: the new Fan Grid was up and running in less than two days. After completion, the customer was very satisfied with the fact that they no longer depended on just one fan to operate their system. The installation was a clean solution and approach that achieved operational cost reductions, more reliability, more flexibility, and ease of control.
