| September 5, 2018

Variable Refrigerant Flow

What is a Variable Refrigerant Flow (VRF)?

Variable Refrigerant Flow (VRF) is an HVAC technology that utilizes refrigerant as the cooling and heating medium. The system uses one outdoor unit, which can be connected to multiple indoor units. The system controls the amount of refrigerant flowing into multiple evaporators (indoor units), enabling the use of many evaporators of different capacities and configurations with one single condensing (outdoor) unit. Like any refrigerant based air conditioner, it operates on the same principles, but has the ability to vary and control the refrigerant flow to optimize performance and energy efficiency.

What are the three basic types of VRF Systems?

Cooling Only: In this mode, all units run on cooling constantly. For example, a cooling only VRF system may be used for computer rooms where there is a cooling need all year round.

Heat pump System: All indoor units can use individual control and set points, but they operate in the same mode of either heating or cooling at any given time.

Heat Recovery: These systems provide simultaneous heating and cooling. All indoor units connected to a heat recovery system can use individual control and set points. This system is ideal when simultaneous heating and cooling is required, maximizing the amount of energy that can be transferred from one zone to another using the refrigerant. For example, an office building with perimeter enclosed offices and an open office area in the core (and meeting rooms) is a good candidate for VRF Heat Recovery.

What makes a VRF system so efficient?

VRF systems operate efficiently at partial capacity because of the compressor’s variable capacity control. The ability to adjust to outdoor conditions is one of the main factors that makes these systems so efficient, compared to the traditional water-cooled systems, chillers and fan coils.

What types of businesses use this technology?

VRF technology has been successfully implemented in various businesses, such as, but not limited to:

  • High or low-rise offices
  • Educational facilities, including schools and universities
  • Health care facilities, including clinics and long-term-care nursing homes
  • Multi Unit Residential Buildings
  • Retail stores

What are the benefits of a VRF System?

For designers: It provides more flexibility for the design team. Equipment is offered in multiple sizes that can accommodate a large spectrum of applications.

For developers: The equipment has less of a footprint than conventional systems. Most VRF indoor units are compact enough to fit inside the ceiling plenum. VRF technology can also be applied in renovation projects, where it is easier and less invasive to install refrigerant piping than larger hot or chilled water piping, along with associated ductwork.

For tenants: It’s a quieter and more comfortable space. VRF technology produces very little noise inside because the compressor is installed outdoors. They also offer precise control as they respond individually to fluctuations in space heating and cooling needs.

What is the incremental cost vs. a typical heat pump?

VRF systems may cost more than traditional systems up front, but this cost can be offset by lower energy bills over time. Each application is different and therefore the incremental costs and the energy savings will be dependent on the building type, size and geometry.

What are the energy savings, and the payback on the additional capital cost?

The payback of a well designed VRF system is typically 4 to 5 years faster than that of a regular heat pump.  However, this is dependent on many factors including; if the selected VRF technology is a heat pump or equipped with heat recovery capabilities. It’s also dependent whether the heat pumps are specified for cold climate operation or standard operation.

What are the first steps to get started?

If you are considering using VRF systems, contact an energy efficiency expert before competing the design phase. From there you may be qualified to receive incentives to help with the cost of a life cycle cost analysis. By assessing multiple energy efficiency measures through an energy model, an energy efficiency expert can recommend the equipment that will have the most benefits you and your tenants while reducing the operating and energy consumption costs.

Get started by contacting our experts today.


Meet the experts at EcoSmart Building Energy Solutions Ltd.


Thank you to EcoSmart Building Energy Solutions Ltd. (ESBES) for taking the time to contribute to our Expert Advice Series with their expert advice on VRF Technology.

ESBES was established in 2017 in Halifax, Nova Scotia. They provide Energy Efficiency Consulting services in the new construction and existing building market. Their project portfolio covers a wide spectrum of applications and buildings including, multi-unit residential buildings, educational facilities, recreation centers, and industrial grow applications.

ESBES was founded by Dr. Hayssam Barhoun who brings more than 18 years of experience in the field of Energy Management, Energy Modeling, and Building Design Optimization. Hayssam is recognized expert in the field of Energy Modeling and became credited to review energy models under several green building and incentive programs.

With specialties in building simulation modeling, energy audits, and mechanical/HVAC design, ESBES provides value to clients through identifying energy management savings and reducing capital costs.