Question: What’s the best way to clear the air: filters, cleaners or just open the windows and let outdoor air in?

The National Center for Energy Management and Building Technologies says all three options work, but using air filters is more energy efficient than opening a home’s windows.

Researchers said that when associated energy costs were considered, studies found that that use of air cleaners could result in energy savings when compared to the dilution effects of opening windows.

The center also found that various off-the-shelf induct air filters, ultraviolet and portable air cleaners are generally effective in removing volatile organic compounds.

According to the report, “sorption” technology- as used in typical air filters - “is an effective strategy for indoor air quality control” in a residential setting.

Products using activated carbon attached to a pleated filter removed between 70 to 85 percent of six out of eight tested VOCs in the laboratory test. A second product, a combination of activated carbon and impregnated with alumina, removed 50 to 60 percent.

Although the tests found that heavier, denser filters were effective in removing heavier low-volatility compounds, the denser filters also tend to cause a drop in the air pressure moving through the filter.

According to officials with the center, the trade-off of higher filtering capability isn’t worth the loss in air pressure. On the other hand, activated carbon did not perform well for removing formaldehyde, and none of the filters were effective for removing dichloromethane.