When it’s time to replace the air filter in your HVAC system, you’ll want to choose a filter that will do the best job possible at keeping the air you breathe clean and comfortable. We have mentioned the importance of looking at MERV ratings when selecting filters, but there are several other types of filter ratings that you need to consider in order to choose the best filter possible.
- Initial efficiency – When talking about air filters, “efficiency” is the percentage of particles or pollutants that the filter removes from the air with each pass. The initial efficiency rates how well air filters perform when they are new. Initial efficiency is often lower than the other efficiency ratings, because as air filters catch pollutants, the dust particles themselves can help block other particles from passing through.
- Sustained efficiency – The efficiency percentage that the filter can sustain over time.
- Dust holding capacity – The amount of dust that a filter can hold. A filter that can hold more dust can potentially last longer before it needs to be replaced.
- Dust spot efficiency – A dust spot test measures how well a filter captures dust under laboratory conditions. A higher dust spot efficiency indicates that the filter removes a higher percentage of dust particles from the air. Dust particles are larger than bacteria or viruses, so a filter can have a high dust spot efficiency and not necessarily have a high overall MERV rating.
- Pressure drop – Also known as filter resistance, pressure drop rates how easily air can flow through the filter. A high pressure drop means that air has a hard time passing through the filter. This can negatively impact the energy efficiency of your HVAC system, which has to work harder to force air through the filter.
Some HVAC systems are designed to work with higher pressure drop or filter efficiency ratings than others. To determine the right air filter for your Kansas City-area home, contact the indoor air experts atOverland Park Heating & Cooling. We will be happy to answer whatever filter questions you may have.
Our goal is to help educate our customers in Overland Park, Kansas about energy and home comfort issues (specific to HVAC systems).
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