There is More Beneath Your Feet than just the Floor: Underfloor Air Distribution

While you’re walking through your office, what do you imagine is beneath your feet? Carpet? Tile? Concrete? Electrical or network cables? What about air? The world of HVAC technology and innovation is rapidly changing. While new trends are initiating changes to long-standing methods of heating and cooling, a not-so-new trend is offering significant benefits to building administrators and building occupants. UFAD (Underfloor Air Distribution) is a system of air distribution in a building that channels air through an plenum under the floor used for heating and cooling. This system is making its mark on the HVAC industry as an alternative method of heating and cooling a building that offers some interesting benefits beyond efficiency including occupant comfort.

Since the middle of the 20th century, UFAD has been used in server rooms and data centers

UFAD Basics

UFAD technology was developed in the 1950s specifically for environments with high heat loads such as computer rooms and control centers. Although UFAD has been used predominantly in computer server rooms and data centers to this day. However, applications of UFAD have been making their way into commercial architecture and providing more efficient, flexible and comfortable environments

UFAD systems distribute air through a plenum and into the room through ports in the floor

Essentially, the conceptual differences between UFAD and conventional overhead HVAC systems are simple. In a UFAD system, a raised space known as a plenum is built in beneath the floor on each story of a building to facilitate air distribution throughout the building. The raised floor is typically constructed of lay-in floor panels that can be reconfigured to suit a wide range of floor plan layouts. Air distribution vents are fit into the floor panels and can be strategically placed throughout occupied spaces in the building. Once the air is distributed into a room, it becomes warmer and rises to be extracted through vents in the ceiling. The basic structure sounds simple enough, but UFAD offers interesting advantages to building owners, architects and building occupants.

Who Benefits from Underfloor Air Distribution?
Building Owners

One of the more exciting benefits that UFAD affords building owners and administrators is improved energy efficiency. The systems require less airflow volume, lower fan power and a lower air supply temperature than a traditional system in order to cool the same space. This more efficient air distribution is able to help building owners bring their facilities one step closer to meeting LEED (Leadership in Energy and Environmental Design) certification standards.

UFAD systems also eliminate the need for duct work that would be fitted into overhead HVAC systems and, thus, reduce the amount of materials required for construction. This not only reduces initial installation costs but also greatly reduces construction time. Standard modular components further reduces construction costs while making construction and maintenance easier. The need for fan coil plumbing systems is also eliminated for more cost effective maintenance.

Another particularly intriguing benefit of UFAD is that it can add value to a building or facility. The added comfort and flexibility provided by UFAD systems, which we will discuss shortly, not only improve the overall appraisal value of a property, but the integrated modular systems increase the lifespan of a building as they can be easily expanded or replaced. The diminished need for additional equipment such as fan coil systems creates more space on each floor and in higher buildings can even allow for additional floors in the same footprint.

UFAD makes diverse floor plan layout configurations possible

Architects / Designers

Flexibility in design is a godsend to an architect or designer. The easy to install modular components and standardized specs of UFAD systems bring a welcomed freedom in structural and aesthetic design when compared to conventional HAVC systems. The minimal ceiling installation also makes the overall installation and construction process quicker and easier. Designers also appreciate the ability to modify designs and configurations even after installation is complete.

Conventional HVACUFAD SystemWith UFAD systems, occupants have the ability to adjust the air supply to their individual space and air is extracted from the room through vents in the ceiling


The comfort level of occupants in a building speaks volumes about the effectiveness of an HVAC system. With UFAD systems, airflow can be controlled at each air distribution vent so that individual users can adjust the supply of conditioned air in their own space. The air distribution method described earlier delivers more uniform temperatures throughout rooms in a building and better ventilation ensures cleaner air by removing dust and particles from the environment. Flexibility in floor plan layouts also allows users to make more efficient and desirable use of space. Easy access to system components can make the cleaning and ventilation maintenance process more convenient as well.

UFAD offers a new dynamic in heating and cooling that is prime for environments such as office buildings, hospitals and schools. The improved efficiency, increased property value, ease of installation and maintenance as well as optimized comfort makes you wonder why we don’t see more of these systems in place today. But the next time you’re walking through a building, believe it or not, you might be walking on air!

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