When looking for better results from your air filter, the focus is often limited to MERV (minimum efficiency reporting value) ratings. Broadly speaking, a filter with a higher MERV rating will deliver better air quality in your home. But there are many other standards besides the MERV rating that apply when assessing a filter’s overall usefulness in any individual setting. Issues like air flow and the filter’s service life also come into play and can affect a filter’s performance under specific circumstances.
Here are some other parameters for getting better results from your air filter:
- The resistance to system airflow caused by a filter is the result of pressure drop. Usually, filters that do a more complete job of filtration have a higher pressure drop. The greater the pressure drop (or filter resistance), the greater the decrease in airflow. Pressure drop increases as a new filter becomes dirty, reducing airflow further and increasing the amount of energy used by the blower fan to circulate air. A lower pressure drop figure usually indicates better energy efficiency and higher comfort levels, so you are always balancing filter effectiveness vs. pressure drop which usually results in more energy consumption and reduced airflow.
- Dust spot efficiency represents the percentage of test dust captured by a filter at a specific air flow velocity. A higher dust spot percentage is an indicator of a more efficient filter. HEPA (high-efficiency particulate air) filters utilized in medical facilities often have dust spot efficiencies exceeding 98%.
- A filter’s dust-holding capacity refers to the total weight of dust a filter can capture before it becomes completely clogged and perhaps damages system components. Dust holding capacity is usually stated in grams of dust and is often utilized to estimate the appropriate length of time between regular filter changes.
- Some new filters require a certain amount of trapped particulates in the media before they reach full efficiency. The initial and sustained efficiency figure compares the filtering efficiency of a new filter versus its efficiency after a specific time span. High quality filters generally have high ratings for both initial and sustained efficiency.
P.K. Wadsworth Heating & Cooling has been the Cleveland homeowner’s trusted source for sales and service expertise since 1936. Ask us for help to get the best results from your air filter.
Paul Wadsworth is the President and Owner of P.K. Wadsworth Heating and Cooling. For 37 years, Paul has been providing heating and cooling services to the Greater Cleveland area. P.K. Wadsworth has been a trusted Cleveland HVAC service company for 75 years. The company understand the area's construction and local heating and air conditioning needs. Paul has an MBA from the University of Michigan and a B.S., Industrial Engineering from Purdue University. He's been President of the Cleveland Air Conditioning Contractors of America and a founding member of the local chapter. Paul was born and raised in Cleveland and has been active in the local community. He resides in Cleveland, Ohio with his wife and two sons.
The opinions and statements contained in this article are for general informational purposes only and are not instructions. Only trained, licensed and experienced personnel should attempt installation/repair. The author assumes no liability for the opinions/statements made in this article. Any individual attempting a repair or installation based on this article does so at their own risk of loss.