Building owners at all levels, residential to commercial-industrial, have been trying to save money. Some have been doing it by cutting things like filter change frequency, without realizing that they wind up spending more money on energy than they would have on the filters they need.
Getting customers back on a regular changeout schedule will help improve their energy consumption - especially if they decided to change filters less often to “save money.”
“When the recession started up, we saw people deliberately delaying filter changes,” said Ron Cox, market manager and Certified Air Filtration Specialist (CAFS) for Kimberly Clark. “That extra period of time, the filter is at its most restricted airflow, and that really kills you.
“People don’t get it; they don’t know what it does to them.” A calculator on Kimberly Clark’s Website shows how the cost of the filter offsets energy costs. Contractors can use tools like this to help customers make truly informed decisions.
“It’s a behavior people didn’t realize they were self inflicting on their energy bill.”
One of the big things in commercial systems, particularly in high-efficiency systems, is to make sure the filters are properly sized and gasketed as they go in, Cox said. “It’s doing more work and a little, small crack will cause more air to bypass that filter.
“It would be too bad to pay for a $100 filter, not seal it properly, and have it operate like a $40 filter. A lot of particulate will follow that airstream. Make sure that you don’t just slap it in there; make sure it’s sealed in place.”
FILTER SELECTIONWith the very broad range of products available, some contractors need a little more information to help them decide which filter is the best one for a particular application.
On the residential side, “If you walk in and you’re going to spec a filter, size is the determining factor,” said Cox. “Most of the installed based out there is the 1-inch filter.”
This limits the full spectrum of what a contractor might be able to do, he said. “A trend in recent years has been to install a larger filter housing. It’s always, always, always nice to have a deeper filter housing, and it doesn’t cost much to put it in. You have a lot more choices on what type of filter to put in there.”
Contractors also need information on whether any occupants have chronic asthmas, allergies, or are elderly. “The choice might be a very high-efficiency filter. In a healthier household, we’re going to go toward the energy efficiency side. If you’re speccing a new system, go with a deeper-pleat filter.” But what’s most important is that contractors gather that information on the occupants.
Regarding efficiency, “You should never go below a MERV 8 for a home,” Cox said. “That’s the minimum level needed to keep the coils clean. Using pleated panels, he said, “the boost in efficiency you get is huge.”
And don’t discount the idea of the filter as something that helps protect the coils. “Most people don’t ever clean the coils on their residential system,” Cox said. “Dirty coils are almost an unrecoverable cost.
“In a residence, the control system in the home drives the system to the set point. If you’ve got a bad filter for whatever reason, that system will run and run and run, trying to get the home to set point. That’s an expensive way to live.”
On the commercial side, he said when people need a special kind of filter, most of the time they know it. “Most buildings are designed for a specific housing. The system says whether you’ve got to put in a rigid bank or a V-cell. It’s not much of a decision to make.” The vast majority use pleated filters.
Key decisions involve efficiencies. MERV 8 is still the minimum to keep the systems clean. However, “They’ve got to be changed fairly regularly or you start getting comfort complaints,” he said.
Still, filter awareness seems to favor the commercial customer, at least in Cox’s experience. “I’ve seen more cases where the residential customer just forgets they have a filter. I think there’s more awareness in larger building’s because it’s somebody’s job.”
BEYOND MERVCox pointed out that “not all MERV-8 filters are the same. We’ve moved away from talking about MERV, to selecting the best filter. It’s a step deeper than MERV.”
When a filter manufacturer decides it’s going to send a filter to the marketplace, a report from the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) determines the efficiency of filters in the E1, E2, and E3 rating (for small to large particle capture; see Table 1). “They will tell you the resistance of the filter to airflow,” Cox explained. “A little matrix shows how components relate to MERV.
“Think about figure skating,” he continued; it judges both technical difficulty and artistic merit. “If you look at E1-E3, you can quickly tell the difference between two filters. Commercial filter distributors absolutely have those test results available.
“If you only go on price, you can make an expensive mistake,” Cox said. “A MERV 8 can still double your energy costs due to resistance. If two filters have the same resistance, test reports will show results for different particles.” You can look for the most efficient MERV for fine particles and the most efficient airflow. “That’s a good choice.”
Residentially, “You just can’t do much in 1 inch. But if you have customers with allergies and asthma, the electrical bill will pale in comparisons to those problems.”
LEED CREDITSLEED accreditation is increasingly popular among commercial customers, and they are gaining awareness among residential customers. “Whenever the housing market comes back, you’ll see LEED housing,” Cox said. “Energy is a big piece of that, so selecting filters with low airflow is part of that.”
Again he points out that MERV 8 is the minimum, but putting in a MERV 13 can get two extra LEED points in commercial applications.
For more information, visit www.ashrae.org and www.kcfiltration.com.
Publication date: 04/19/2010