Rating Furnace Filters For Quality
Shopping for decent furnace filters can be very confusing for somebody who is not intimately familiar with the industry. Some filters seem good enough to do the job but cost as little as $1 and need to be replaced every month, making them seem suspicious at best. Other, supposedly better, filters cost upwards of $20 but only last for three months. Trying to pick between the range of options can be tricky, and it is easy to be left with a piece of junk filter that cost you twice as much as it should have or only works half as well as you need.
However you may have noticed something called a MERVE value listed on your box of furnace filters. This is the Minimum Efficiency Reporting Value of the filter in question, or the generalized rating system used to determine quality. MERVE ratings range from 1 to 16, with 16 being the best for home use. High Efficiency Particulate Air (HEPA) filters can go higher than 16, but they greatly reduce airflow and are not always the best option. A disposable filter is usually rated somewhere between 1 and 4, meaning that is barely better than junk. Pleated filters, on the other hand, take up the majority of ratings (5-13) and offer good filtration without restricting the airflow more than necessary. Anything between 13 and 16 can filter out some of the smallest particles, and are usually found only in labs and hospitals.
Knowing what the MERVE rating on your filters means will save you a great deal of trouble when trying to determine the value of the pack of filters that you are purchasing. Try to shoot for a pleated filter with a mid-line rating to get the most bang for your buck, or choose an even higher rating if you suffer from constant allergies.