Cost of poor IAQ in U.S. estimated at $160 Billion

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June 1st, 2009

WEB EXCLUSIVE: Don’t Skimp on Air Filtration Even When Budgets are Tight

This Web Exclusive comes from Tsiropoulos, Market Manager, -

Filtration.

Virtually everyone has been learning to cope with tough economic

conditions. For individuals, the loss of jobs and cuts in pay mean

tighter budgeting at home: forgoing vacations, dinners out, and luxury

purchases. For companies, reduced income and profits often means taking

a hard look at line item expenses in an attempt to boost the bottom

line.

One line item that may come under scrutiny among facility managers

(fms) looking to reduce maintenance expenses is the HVAC system. It may

seem perfectly logical, for example, to save hundreds or even thousands

of dollars per year in purchasing costs by reducing the frequency of

air filter change-outs or by downgrading to a lower-priced filter.

Smart firms should realize the small amount of money saved by reducing

or eliminating air filter purchases or by purchasing lower priced (and

lower efficiency) filters pales in comparison to the energy and

operating costs that can be saved by maintaining a robust air

filtration maintenance and upgrade program.

The Role of Air Filtration

Effective air filtration provides the primary defense for building

occupants and HVAC equipment against pollutants generated within a

building as well as pollutants from air drawn into a building from the

HVAC system. It affects the quality of indoor air, which can be two to

five times as polluted as outdoor air.

Poor indoor air quality (IAQ) is more than just a nuisance. The cost

of poor IAQ to the overall U.S. economy is in the neighborhood of $160

billion in terms of healthcare costs and reduced productivity among

workers. Moreover, studies have shown that when indoor environments are

improved, businesses can realize up to a 20% improvement in

productivity—another strong incentive to pay close attention to

enhancing IAQ through proper air filtration.

While air filters play a key role in a building’s IAQ, they also

play a major part in the energy consumed to operate the building’s HVAC

system. This makes air filtration a wise target for cost reductions as

long as the right strategies are followed.

HVAC Expenditures: Myths vs. Facts

There are a number of ways that facilities may try to save money and

reduce their HVAC system budgets. For example, facilities may try to

delay filter change-outs or upgrades, or they may want to downgrade

from high efficiency pleated filters to lower efficiency and lower

priced panel filters. These strategies may be short sighted and

contrary to cost saving goals; especially when one considers that the

U.S. Department of Energy suggests enhancing operating efficiency of

HVAC systems can reduce energy bills by up to 20% without significant

capital investment.

Myth: Delaying filter maintenance (i.e., change-outs) will help save money.

Fact: While it is true that purchasing fewer filters reduces

initial expenses, delaying filter change-outs also causes the filter to

run more days at peak energy usage. It doesn’t take long for peak usage

cost to offset any savings in the filter price. (See chart below.)

That’s because energy use is the largest operating cost involved in air

filtration. A filter’s energy consumption accounts for a full 80% of

its total life cycle costs. Moreover, the cost of the energy used to

operate the filter can be more than eight times the initial purchase

price of the filter itself.

It comes down to physics; the energy used to operate filters is

directly proportional to the airflow resistance of the filters. The

more resistance (due to clogged filters that aren’t changed out as

frequently as needed), the more energy is needed to push air through

the filter. Resistance typically increases as filters remove more and

more contaminants from the air. This filtration is essential for air

quality and protection of HVAC equipment, but it comes at an extremely

high cost when filter change-outs are delayed.

Delaying filter maintenance not only increases energy consumption,

it also increases CO2 emissions; the extra energy consumed by dirty

filters drives up energy production and greenhouse gas emissions.

According to the U.S. Environmental Information Administration, 1.354

pounds of CO2 are released into the atmosphere for every 1 kWh of

electricity produced, making delayed filter maintenance extremely

costly to the environment. Plus, because America generates close to 50%

of its energy by burning coal, reducing HVAC energy consumption also

helps conserve natural resources.

Myth: There is little economic incentive to upgrade a building’s air

filtration system.

Fact: Some commercial and institutional buildings in the

United States are still using pre-WWII technology in their air

filtration system—panel filters. Sometimes called “throw-away†filters,

they are constructed in much the same way they were made 75 years ago

and are among the lowest priced filters in use today.

For years, it was believed that panel filters provided adequate

filtration to keep HVAC systems running cleanly and efficiently.

However, a recent study found that panel filters do not provide

adequate protection to HVAC equipment, allowing for particle deposits

to build on fans and heating/cooling coils, a problem known as

“fouling.†Fouling greatly reduces airflow through the HVAC system and

prevents heat transfer in the coils, all of which can add up to a

significant increase in energy costs. Fouling also leads to expensive

and time consuming fan and coil cleaning.

Myth: Air filtration is not in the budget.

Fact: One of the biggest traps that commercial facilities fall

into regarding budgeting for air filtration is the NIMB (Not in My

Budget) factor. In many cases, one department (and budget) is

responsible for purchasing air filters and filter service contracts

while another is responsible for energy expenditures. The problem

inherent in this system is that the filter purchaser can easily and

quite innocently make a costly decision for the enterprise by choosing

to buy filters without considering the energy consumption and system

operating implications described above.

Reducing HVAC-Related Costs

It is important to remember that filters will only support good IAQ and

perform as specified when they are maintained correctly. There are

three important factors for proper air filter maintenance and reduced

operating and energy costs: following the proper filter change-out

frequency and installation steps; upgrading from panel filters to

pleated filters; and choosing a filter with a lower resistance to

airflow.

Proper filter maintenance is crucial to keeping HVAC ductwork clean.

If dirt accumulates in the ductwork and if the relative humidity

reaches the dewpoint so condensation occurs, then it can become a

breeding ground for bacteria and mold.

For all of these reasons and more, it is important to establish the

appropriate filter change-out frequency. However, filters should be

changed immediately if they become wet, if microbial growth on the

filter media is visible, or when the filters collapse or become damaged

to the extent that air bypasses the media.

It is crucial to pay close attention to filter installation during

change-outs. The goal is to avoid bypass air (air that does not go

through the filter) which occurs when filter media is not properly

sealed in the filter frame, when filters are not properly installed and

gasketed in filter racks, or when air handler doors and ducts are not

properly sealed. Bypass air can cause contamination in housings, coils,

fans, and ducts and can increase system operating costs; fouled heat

exchangers have diminished heat transfer performance and increased

pressure drop, leading to increased energy use and decreased heating

and cooling performance. Bypass air can also decrease a filter’s

performance and negatively affect IAQ.

Keep in mind that bypass air tends to have a larger effect on high

performance filters. A 1mm gap causes a MERV 15 filter to perform as a

MERV 14 filter, while a 10mm gap causes a MERV 15 filter to perform as

a MERV 8 filter.

One way to lessen the frequency of and purchase costs related to

filter change-outs is to choose a high-capacity pleated filter which

typically has an extended filter life along with a low resistance to

airflow Pleated filters certainly offer advantages over “throw-awayâ€

panel filters.

First, while panel filters typically yield performance only in the

MERV 1 to 4 range, pleated filters are available with performance up to

MERV 13, allowing improved efficiency in capturing both large and small

particles. Second, upgrading from panel filters to pleated filters

provides cost savings advantages, thanks to decreased routine

maintenance and energy costs. Because panel filters allow HVAC system

components to become dirty, operating efficiency decreases and energy

costs to operate the inefficient system can increase. The small amount

of money saved by purchasing a lower priced panel filter can be

substantially offset by even a slight reduction in the operating

efficiency of the system.

One of the easiest ways to realize HVAC related energy costs savings

is to switch to a filter with a lower resistance to airflow. When

filters have a lower resistance to airflow, the HVAC system motor needs

to overcome less resistance to deliver the required air flow, thus

reducing the motor’s energy consumption.

Airflow resistance is calculated with a pressure gauge, which

indicates Water Gauge (WG), the measure of the pressure required to

lift a 4C-degree column of water a certain distance in the air. For

example, a 0.05†WG reduction in a filter’s initial pressure drop (also

known as airflow resistance) can reduce energy costs by up to 3.5% or

about $7 per filter, while a 0.20†WG reduction in a filter’s initial

pressure drop can reduce energy costs by up to 10% or about $28 per

filter. While an energy cost savings of $28 per year may not sound like

a lot, those cost savings are per filter, not for an entire HVAC system.

Skimping on air filtration during a tough economy has the potential

to put facilities even deeper in financial trouble. It can negatively

impact IAQ which can increase costs relating to worker health and

productivity.. It can also increase HVAC system operating and energy

costs. While reducing the frequency of filter change-outs or

downgrading to a lower-priced (and lower performance) filter may seem

like good ways to reduce expenditures, they are not true cost-savings

strategies. Because energy costs are the largest component of an air

filter’s total life cycle cost, it is imperative for facilities to look

beyond the line item purchase price of filters when seeking to reduce

their overall costs and instead look at the initial and sustained

pressure drops of different filters.

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