By Jim Rosenthal, CAFS A MERV 13 filter and a box fan? It is definitely not a new idea. It has been floating around for years. However, in the era of Covid-19, it is time to take all of the tools out of the toolbox. This simple, inexpensive air cleaning device can remove substantial amounts … More
Indoor Air Quality
ASHRAE Research Project Report On Air Filters Raises More Questions Than it Answers
In March of 2013 the results of ASHRAE Research Project Report 1360-RP was made available for distribution. The 415 page Report is entitled “How Do Pressure Drop, Efficiency, Weight Gain, and Loaded Dust Composition Change throughout Filter Lifetime. The Contractor was RTI International and the Principal Investigator was Kathleen Owen. Ms. Owen presented the findings … More
Selecting the Right Filter to Improve Indoor Air Quality
Many HVAC technicians falsely believe that the only type of filter to use in a system is a fiberglass one-month “throwaway.” They are convinced that the only purpose of a filter is to protect the equipment from dust and debris and that the need for the better air flow provided by the fiberglass filter overrides … More
How Concerned Should We Be with the Filtration of Sub-micron Sized Particles in Indoor Environments?
In recent years more and more studies have been published showing that increased levels of sub-micron sized particles in the air result in higher levels of inflammation. This inflammation has been found in the cardiovascular and the respiratory system of exposed individuals resulting in increased morbidity and mortality. Increased levels of heart attacks and asthma attacks … More
Comparing the Efficiency of Different Types of MERV 8 Air Filters in a Room Environment
There has been a great deal of discussion about the accuracy of filter testing. This discussion has covered everything from materials (test dust) to methods to reproducibility and much more. But the problem with these discussions is that they do not deal with the effectiveness of filters in indoor environments. After all, particles in an indoor … More
How to Use Proper Filtration and Differential Pressure to Help Control Contamination During Health Care Facility Construction
Between July and September of 1994 technicians in the clinical microbiology laboratory of Wilford Hall Medical Center at Lackland Air Force Base in Texas found Aspergillus niger in 17 clinical samples submitted for 15 patients at the hospital. This caused a great deal of consternation for two reasons: 1. The incidence of Aspergillus niger … More
What is a MERV? Air Filter Testing Explained
It is important to understand what a MERV (Minimum Efficiency Reporting Value) means when it comes to air filters. This article explains how a MERV is calculated and gives information on how it should be used to evaluate air filters.
How to Select the Right HVAC Filter
What is the right filter for your job? Today, more than ever, there are a large variety of filter choices for every application. Filters come in a wide range of efficiencies, pressure drops, depths, media types and methods of filtration. There are filters that will withstand very wet environments as well as filters designed for … More
There is Still Something in the Air
The May 2005 issue of Consumer Reports presented new concerns about ionizing air cleaners (ionizers). The magazine reported the results of tests they had conducted with 5 ionizers including the Ionic Breeze sold by Sharper Image, the market leader. Other units tested included the Brookstone Pure-Ion, the Ionic Pro, the IonizAir and the Surround Air. … More
Ozone Reactions with Skin Oils Create Irritants
Ozone found in indoor environments reacts with human skin oils to produce chemicals that irritate the skin and lungs according to researchers in Austria and the United States. In a study published in the Proceedings of the National Academy of Science Armin Wisthaler of the Leopold Franzens University in Austria and Charles Weschler of Rutgers University … More