Clear the Air: Use lifecycle costing with HVAC filter media
In 2001, the industrial sector accounted for about 39 percent of secondary energy use in Canada and 34 percent of related greenhouse gas emissions, according to Natural Resources Canada. Motor-driven systems use 39 percent of all electrical energy consumed in Canada, adding up to an estimated $14 billion annually.
While companies can do many things to reduce energy use in their plants, one area that may be overlooked involves the heating, ventilation and air-conditioning (HVAC) system, which can account for up to 35 percent of the energy used in a manufacturing facility. A simple change to the HVAC air-filter system can make a big difference.
Air filters and energy
HVAC filters play a key role in the HVAC system. They remove contaminants from the air that pass through the system to building occupants, and protect the HVAC equipment from dust. Filters also play a significant role in the energy consumed to operate the system.
The energy used by HVAC systems is based on the resistance of the air passing through the filter—the lower the filter’s resistance, the lower the energy consumption will be. It’s really the filter media, however, that has the biggest effect on minimizing energy consumption.
Companies have to understand that the cost of energy used by filters far outweighs the cost of the filter itself. In fact, energy costs can be 10 times the initial filter cost for a standard pleated filter; four to five times the initial filter cost for higher efficiency final filters.
In a typical scenario, one might use initial cost as the primary criteria in choosing one HVAC filter over another. This might not result, however, in the correct filter choice for maximizing long-term energy savings.
During the filter selection process, lifecycle and energy costs and filter-pressure drop should all come into play. The three major components of lifecycle cost for HVAC filters include initial investment and maintenance, energy consumption and disposal.
On average, the cost of energy accounts for an astounding 81 percent of the total lifecycle cost of a filter system. The initial investment and maintenance accounts for 18 percent, and disposal accounts for one percent.
How can lifecycle costing of filters be applied to energy efficiency? Development of new materials has given the filter industry a chance to produce lower pressure-drop media, while maintaining high particle capture efficiencies. This leads to improved air quality (IAQ) and reduced electricity costs.
Switching to a lower pressure drop filter is one of the easiest changes for facility engineers and maintainers to make to reduce energy costs. With a lower pressure drop filter, the HVAC system motor needs to overcome less resistance to deliver the required airflow, thus reducing the motor’s energy consumption.
The lower pressure drop translates directly into energy savings. Alternatively, one might choose to use the savings associated with a lower pressure drop filter as a means to upgrade filter efficiency. Current industry paradigms suggest that increasing a filter’s efficiency means increasing its pressure drop, but this isn’t always the case.
As an example, there are commercially available 95 percent efficiency synthetic media filters that have the same pressure drop as 65 percent efficiency glass media filters, providing the ability to increase filtration efficiency by 30 percent—without increasing energy costs. This upgrades IAQ with no energy penalty.
Most facility engineers/maintainers agree that filtration efficiency comes first. Beyond the filter’s efficiency rating, buyers and specifiers often use filter price as the next decision-making criteria. After examining lifecycle cost and energy saving opportunities, the key criteria should be energy consumption, as indicated by the initial pressure drop of the filter.
When considering the energy costs of various filter technologies, ask your filter supplier the following questions:
• At a given performance level, how much money could be saved by using a lower pressure drop filter?
• What pressure drop reduction offsets the difference in initial filter price?
• How much of my initial filter costs does the energy cost savings offset?
Focusing on total lifecycle costs versus initial price and maximizing filtration efficiency, while minimizing pressure drop, will enable companies to achieve better IAQ, reduce equipment maintenance and lower energy costs.
Dave Matela, CAFS (certified air filtration specialist), is market manager, Non-woven Fabrics, for Roswell, GA-based Kimberly-Clark Filtration Products. You can reach him by email: email@example.com.