The indoor air quality (IAQ) in a space affects the function and any costs to operate in that space. The aesthetics of any equipment may also be an important factor. Having a good level of IAQ enhances productivity, decreases absenteeism, increases the building’s value, and reduces the owner’s liability. One way to achieve thermal comfort of interior spaces is through the use of High Volume Low Speed (HVLS) fans. These fans move large amounts of air within occupied spaces. Because this movement supports ventilation, the result is the cooling of occupants.

HVLS fans move gentle volumes of air vs. the air movement of high speed fans. This gentle air circulation achieves cooling and de-stratification. HVLS fans provide gentle, quiet, energy efficient, and greater amount of air movement with a smaller size than high speed fans. One cubic foot of air is about .08 lbs. Some HVLS fans move up to 19 lbs. of air.

HVLS fans are lighter and quieter with fewer blades than conventional high speed fans. The low velocity pressure vs. the higher velocity of smaller high speed fans allows a larger HVLS fan with lower speeds to move the same amount of air. This results in better and more efficient cooling capacity. HVLS fans include large floor column or large air jet fans. HVLS fans can make a space from 6 to 8 degrees cooler. In addition, thermal comfort and IAQ are intrinsically bond together. An HVLS fan increases air movement to all areas of the space. This includes moving air across the skin, resulting in an additional 5 to 7 degrees of cooling. In a heated space, the HVLS fan can increase the heating capacity by moving the heated air down.

The Thermal Comfort Credit is one of the possible LEED credits for Building Design and Construction (BD+C) for Indoor Environmental Quality (IEQ). This credit evaluates the goals, systems, and controls of a building’s thermal comfort strategy. There is also evaluation of a standard for comfort control. The Thermal Comfort Credit could apply to new construction, core and shell, schools, retail, data centers, hospitality, healthcare, warehouses, and distribution centers. As with any LEED project, it is important to have the involvement of the owner, architect, and engineer as early as possible in the certification process. One strategy is to have a flexible dress code that will allow occupants to wear seasonal attire to help them achieve thermal comfort. Another strategy is to provide thermal controls to occupants. This could be through a thermostat, operable windows, and/or local temperature controls. Not only do these steps result in more thermal control, there is the potential for a 2.7% to 7% productivity gains.

Another alternative is to design the space using the relevant ASHRAE standards. This includes considering human thermal comfort by examining factors like clothing, humidity, and activity. Because of varying individual responses that might be based on age, gender, and geographic origin, responses to these factors are subjective. However, there are equations that allow a more objective measurement. In environments such as foundries, construction sites, and bakeries, some occupants may be subject to heat stroke, exhaustion, and/or fainting. Shared group thermal comfort controls can address some of these issues by controlling at least one of the factors of air temperature, radiant temperature, air spread, or humidity. Digital touchpads and controllers may offer additional ease of access. Other options are to use an automatic fan and reversing the fan direction to destratify the air.

Enhanced Indoor Air Quality (IAQ) strategies go beyond minimum IEQ prerequisite and minimum IAQ performance. Projects could address issues like sweating slab syndrome which is moisture on the interior concrete slab. This results in a slippery surface that can lead to mold growth and damage to the machinery or building structure. Sweating slab syndrome is especially problematic in food environments. Another issue connected to IAQ is sick building syndrome. A faulty air vac could lead to occupants experiencing headaches, eye and noise irritation, dizziness, and nausea. Fans are a way to improve circulation of the air by helping to exhaust polluted air, especially with heating, ventilation, and air conditioning (HVAC) systems consisting of smaller units. Furthermore, fans have a direct impact on reduction of building cost by assisting air conditioning or the reverse fan action for heating spaces. Additional concerns of minimum IEQ prerequisite and minimum energy performance include sinks resulting from cold air leaving a space. Some of these sinks may be caused by leaks via windows and doorways. This results in larger energy loads.

Some building projects might explore obtaining even more LEED credits by pursuing the Energy & Atmosphere category. This credit is achieved through evaluation of building orientation, site selection, and materials. There are several options for achieving this credit, including modeling a whole building simulation of energy use. ASHRAE is another standard that looks at energy efficiency and power usage in large building. HVLS fans have not been included in the past, but is an expected addition to the standard.