VRF Systems for Historic Buildings

Learn why Variable Refrigerant Flow (VRF) is a viable option for historic building renovations.

August 7, 2018

Renovations and restorations of historic buildings can present a wide range of challenges for building systems engineers. When the renovation includes an HVAC additions or updates, many limitations such as preservation, available space, coordination, and budget constraints are typically present. One viable solution is the installation of a Variable Refrigerant Flow (VRF) system.


A VRF system consists of a single outdoor unit and multiple indoor units that serve individual rooms or zones. The capacity of each indoor unit can effectively match the space it is serving, allowing for greater zoning options in the building. The system is also uniquely capable of simultaneous heating or cooling different zones. The ability to utilize any combination of indoor unit configurations (i.e. ceiling, floor, or wall mounted) gives greater flexibility than that of a conventional ducted system.

Building Preservation

Utilizing a VRF system means the need for ductwork is limited to that which provides required fresh air to the building via dedicated outside air units. The system requires minimal penetrations to the exterior and the outdoor units are smaller and more lightweight which minimizes disturbance to the existing structure and, in many cases, reduces the need for additional structural reinforcement. An additional and appealing quality is that the inverter driven compressor greatly reduces noise generation when compared to a conventional system.

Cost Factors

It is also important to point out how the utilization of a VRF system may be the best option for the project budget. The lack of a complex system of plumbing and ductwork reduces installation cost and eliminates many of the coordination issues. While the system does have a higher initial cost, the efficiency of VRF often leads to lower utility costs over time.


While utilizing with a conventional ducted system will get the job done, there are unique requirements and limitations that are inherent to historic building projects. The combination of flexibility, modularity, and overall cost benefits of VRF systems should make them a top choice for conditioning historic projects.

Founded in 2003 and re-branded in 2018, HTW is an Arkansas-based firm specializing in architecture, engineering, planning, and interiors. Since its formation, HTW has become one of Arkansas most innovative and fastest-growing architecture and engineering design firms, providing services to clients across the United States.

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