There are a lot of choices when shopping for replacement filters for your heating & cooling system. There are flat filters, pleated filters, 1″ filters, 2″ filters, 4″ filters, and even carbon filters. All of these can be found in typical residential and small commercial systems.
So what is best for you?
The answer is not as simple as you might think. The real answer is the best one that your system is designed to handle.
Efficiency (MERV vs MPR)
MERV is the Minimum Efficiency Rating Value that was established by the American Society of Heating & Refrigeration Engineers Society (ASHRAE). MPR is Micro Particle Rating and was established by 3M for their filters. On either scale, the higher the number the more efficient the filter is. Unfortunately it also means more air resistance and that makes your blower work harder.
1″, 2″ and 4″ are very common. When using a pleated filter with a thicker dimension, you gain more filtering surface area. The filter lasts longer and total air resistance is lower for an equal efficiency that is thinner.
Most residential systems are designed for 1″ filters. A MERV 8 or MPR 600 pleated filter is usually safe to operate efficiently without placing too much stress on your blower. With 2″ you can safely to go MERV 11 or an MPR of 1200. With 4″, MERV 13 or an MPR of 2200.
Contrary to popular belief, a better filter doesn’t necessarily help with odor control. Odors may be attached to large particles such as pet dander and are trapped in the filter with the pet dander. But many odors such as cooking odors are attached to smaller particles or gasses and simply pass through typical filters. Carbon filters are the only method to trap and remove these odors.
Regardless of which filter you choose, make sure it is the proper size and fits well in your system.