HOW ABOUT 'UFAD'? (Under Floor Air Delivery). UFAD is a common solution in commercial projects. Should UFAD be considered for a home? In a two or three story home, under floor becomes easily doable by simply placing ducts within the floor joist systems and then using floor registers. New High Velocity HVAC systems use small ducts that can be easily routed down through walls into a floor system. UFAD ducts can by economically cast into a residential slab. But why consider this? Because UFAD air can be 8 to 10 degrees cooler* or warmer than ceiling delivery air and provide the same level of comfort. That saves energy. Other studies show that because conditioned air in an under floor plenum is in contact with the slab's concrete, additional energy and cost savings strategies become available. The concrete slab's thermal mass provides a consistent cool air or warm temperature thermal mass reservoir. This saves even more energy and money!
* 12-08 UFAD Case Study in Enviromental Design & Construction magazine by Michael Jouaneh "The New York Times Building features a versatile underfloor air distribution (UFAD) system designed for comfort and efficiency. With this underfloor air system, The New York Times Company is able to air condition 10 degrees warmer than a typical system — at 68 degrees Fahrenheit — and gently pump this chilled air up from the floor rather than pushing air down from the ceilingat high velocity. Cooler air naturally fills the lower area of the room and rises when it hits warmer objects such as people or computers. The warm air then exits through vents in the ceiling. This system not only saves energy, it also ensures a much more regulated, comfortable temperature throughout the space..."
After UFAD, what else can be considered a 'green' floor? If you are considering an elevated floor or crawl space floor, I would say one of the greenest floor systems is a SIP subfloor(structural insulated panel). This sealed strong super-insulated floor system eliminates the problems that occur with lumber framed crawl space floors (air leakage, moisture control, insulation breakdown, vermin). A SIP subfloor can is perfect for UFAD HVAC duct work.
What's Next? We could could say that a green floor has to be covered with sea grass hemp carpet like our office (no joke). Or maybe it must be a bare concrete floor with stain like our building's central hallway. Flooring choices will vary greatly by the application of each room. Floor manufacturing companies have devoted big marketing efforts to explain just why their brand of carpet is greener, or why you should only choose their bamboo parkay, or why hardwood is not green unless it is reclaimed.
But in the end those choices must be based personal opinions and functional needs. Sea grass hemp carpet sounds, and certainly smells green. But since I was not the builder or the supplier I have no idea of the potential for offgassing from the adhesives, binders, and foam rubber substrates. Similarly, the stain concrete hallway may use a water based urethane coating that may never be a problem at all, or conversely may only be proven to have been a very bad choice when I am 80. I will leave these material and offgasing investigations to other experts. This webpage will attempt to present other more measurable environmental aspects like a floor system's energy and structural performance, durability, ease of construction, and broad environmental impact.
HOW ABOUT 'UFAD'? (Under Floor Air Delivery). UFAD is a common solution in commercial projects. Should UFAD be considered for a home? In a two or three story home, under floor becomes easily doable by simply placing ducts within the floor joist systems and then using floor registers. New High Velocity HVAC systems use small ducts that can be easily routed down through walls into a floor system. UFAD ducts can by economically cast into a residential slab. But why consider this? Because UFAD air can be 8 to 10 degrees cooler* or warmer than ceiling delivery air and provide the same level of comfort. That saves energy. Other studies show that because conditioned air in an under floor plenum is in contact with the slab's concrete, additional energy and cost savings strategies become available. The concrete slab's thermal mass provides a consistent cool air or warm temperature thermal mass reservoir. This saves even more energy and money!
After UFAD, what else can be considered a 'green' floor? If you are considering an elevated floor or crawl space floor, I would say one of the greenest floor systems is a SIP subfloor(structural insulated panel). This sealed strong super-insulated floor system eliminates the problems that occur with lumber framed crawl space floors (air leakage, moisture control, insulation breakdown, vermin). A SIP subfloor can is perfect for UFAD HVAC duct work.
But in the end those choices must be based personal opinions and functional needs. Sea grass hemp carpet sounds, and certainly smells green. But since I was not the builder or the supplier I have no idea of the potential for offgassing from the adhesives, binders, and foam rubber substrates. Similarly, the stain concrete hallway may use a water based urethane coating that may never be a problem at all, or conversely may only be proven to have been a very bad choice when I am 80. I will leave these material and offgasing investigations to other experts. This webpage will attempt to present other more measurable environmental aspects like a floor system's energy and structural performance, durability, ease of construction, and broad environmental impact. 
