Occupant comfort is the driving force in building design and is the reason buildings have HVAC systems and insulation. As shown on the graph to the right, productivity decreases significantly if a building is too warm or too cold. Our BioPCMTM makes spaces more comfortable by stabilizing surface, air, and radiant temperatures in the zones where it is installed.
The financial value of comfort enhancement can greatly exceed the value which is possible from increased energy or maintenance savings. In most buildings the annual cost per square foot to pay employees far exceeds any other cost. Enhanced comfort increases productivity and even a small increase in productivity can provide significant cost benefits. Numerous studies have shown that productivity is correlated with temperature. Comfort conditions are maintained within the optimal productivity zone a greater percentage of time when our BioPCMTM is installed.
- According to the DOE the average annual energy cost per square foot for commercial buildings is $2.29. Assuming forty percent of the energy is used for heating and cooling, then HVAC energy costs are $.90.
- According to ASHRAE the average annual cost per square foot for HVAC maintenance is $0.50.
- The average square feet per person for an open office is 200. Assuming a median annual income of $40,000, the average cost per square foot for salaries paid to employees is $200.
Thus the cost of employee salaries is more than 100 times greater than that of the combined cost of HVAC energy and HVAC maintenance. An increase in employee productivity by 1 percent creates more value than totally eliminating the HVAC energy and maintenance cost of a building. The bottom-line; enhanced comfort increases productivity, and productivity is the most valuable thing in buildings.
Over the last few decades, researchers have been exploring ways to predict thermal comfort. Research based, mathematical models that simulate occupants’ thermal response to their environment have been developed and are included in the EnergyPlus simulation software. The most notable models have been developed around the work initially completed by P.O. Fanger. He deduced an expression for optimal thermal comfort based on metabolic rate, clothing insulation and environmental conditions. The final equation for optimal thermal comfort is fairly complex and need not be detailed here. Current ASHRAE 55 comfort standards, which are based on his original work and the assumption that people dynamically change their clothing based on the season, (i.e. sweater in winter, t-shirt in summer) count the hours of modeled discomfort within a building. Our BioPCMTM moderates surface temperatures and air temperatures resulting in buildings being more comfortable in scientifically measurable ways.