By: Robert Martin, CAFS, Associate Category Manager, Kimberly-Clark Professional Filtration |
Building professionals seeking to improve the environmental sustainability of their buildings would be wise to evaluate the air filtration in their building’s HVAC system. Effective air filtration provides a prime defense for building occupants against indoor airborne pollutants, and they also play a role in a building’s energy consumption — two key focus areas for many green building programs.
Not all air filters are created equal. Indeed, there are marked differences among various types of filters and especially filter media when it comes to indoor air quality (IAQ) and energy consumption. Choosing the right filter media and overall air filter design can provide high-efficiency removal of the submicron respirable particles associated with health and productivity problems. It can also help to reduce energy consumption and costs associated with operating an HVAC system.
Cleaner Indoor Air
Superior indoor air quality is a key tenet of environmentally sustainability and green building initiatives. Providing superior IAQ can improve health, work performance and school performance, as well as reduce health care costs, and consequently be a source of substantial economic benefits. Electret-treated filter media is particularly useful in increasing the capture efficiency for submicron particles – the particles 2.5 microns and smaller that travel to the deepest part of the lungs where they can cause health problems.
The right air filtration strategy can help buildings reduce their HVAC energy consumption and cost. The key is to select air filters with lower airflow resistance, such as those with electret-treated media. Unlike electret-treated media filters, filters with mechanical-only filter media must use extremely fine fibers or dense structures to achieve high efficiency in capturing submicron particles, which creates airflow resistance in the filter. The more resistance there is, the more energy is needed to push the air through the filter. This translates into higher energy consumption and costs.
A filter system’s energy consumption is also affected by its change-out schedule. Some building professionals, in an attempt to reduce air filtration costs, may be tempted to delay change-outs. But the small amount of money saved by reducing air filter purchases pales in comparison to the energy and operating costs that can be saved with a robust air filter maintenance program. That’s because delaying filter change-outs causes the HVAC system to run more days at peak airflow resistance and energy usage.
The right air filtration strategy can help buildings meet prerequisites and obtain credits under the U.S. Green Building Council’s LEED program. For example, under the LEED O&M: Existing Buildings program, there are a number of prerequisites buildings must meet to participate in the program, one of which may be impacted by the type of air filter used in the building’s HVAC system:
- Facility Maintenance and Renovation Policy — To reduce the environmental harms associated with the materials purchased, installed and disposed of during maintenance and renovation of buildings. The policy must address indoor air quality as follows:
- Do not operate permanently installed air handling equipment during construction unless filtration media with a MERV 8 is installed at each return air grille and return or transfer duct inlet opening such as there is no bypass around the filtration media.
- Develop a procedure to, before occupancy, replace all filtration media with the final design filtration media.
Buildings can also obtain a LEED credit in the following area through the proper air filtration strategy:
- Enhanced Indoor Air Quality Strategies — To promote occupants’ comfort, well-being and productivity by improving indoor air quality. One credit can be obtained by installing particle filters with a MERV of 13 or higher. In addition, buildings must establish a regular schedule for maintenance and replacement of filtration media according to the manufacturer’s recommended interval.
LEED O&M: Existing Buildings prerequisites and credits can also be achieved by following environmentally favorable purchasing and waste management policies. For example, some high-performance filters use less media than others, which is a good way to reduce raw material usage and waste. Some filter media is also made without binders, which can cause off-gassing. It’s best to consider the entire product lifecycle when selecting filters — from raw material sourcing to manufacturing, from packaging to transport, and from design and usage to final disposal — to ensure you’re selecting the most environmentally sustainable solution.