The effects of improved residential furnace filtration on airborne particles

Abstract

Forced air furnaces with distributed ducting systems have always had an air filter, but traditionally the filter quality was only adequate to protect the furnace fan and heat exchanger from debris. In the past several years, there has been an increasing number of more effective particulate filters that are being marketed to reduce airborne particulate or dust. These include upgraded panel filters, passive electrostatic, active electrostatic, and HEPA or near-HEPA variants. Consumers are bewildered by the lack of standardized and comprehensible performance results and need better advice on whether it would be useful for them to upgrade their current furnace filter. In order to help them make these decisions, the whole range of available furnace filters were tested in six occupied houses. The filter efficiency was determined by particulate measurement in the ducting system before and after the filter. Indoor particulates were measured in a bedroom and living room, and outdoor levels were monitored simultaneously. Testing encompassed several weeks in each house, and the results are available in the whole range of particle sizes. The project also looked at the air-cleaning effectiveness of a stand-alone air cleaner and at the ozone production of electrostatic precipitators installed in 20 houses. Testmore » results will be helpful in specifying suitable filtration for houses.« less