A Guide to Understanding HVAC Filter Maintenance

By in , ,
A Guide to Understanding HVAC Filter Maintenance

You may have heard this before but it’s worth hearing again. Regular filter changes are the single most important factor in HVAC maintenance for your Waterford, MI home. Based on what our Kotz Heating, Cooling & Plumbing technicians hear from our customers, there is still some confusion about the types of filters and how often they should be changed. Let’s spell out some of the specifics.

How often to change

This can depend on the type of air filter (more on that below) but they should be changed every 30 to 90 days. Your environment is a key factor here. If you live on a dusty road or have multiple pets you should change it more often. 

Correct size matters

This could probably go without saying but buying the right size air filter matters. If it doesn’t fit your system precisely it will allow unfiltered air to enter the air handler which can quickly damage components.

Understanding MERV

Filters have what’s called a MERV rating. The higher the number, the smaller the particles it can trap. You can break these ratings down into some broad categories:

MERV 1-6—These are the typical one-inch thick fiberglass filters. They are inexpensive and you can buy one in just about any store. Kotz doesn’t recommend this type of air filter because they remove only about 10% of the particles in the air. If you are using these, they should be changed every 30 days.

MERV 7-13—These are normally pleated and made of polyester or cotton. They are also one-inch thick and described as medium efficiency. This is usually the best type of air filter for residential applications, removing about 30 to 50 percent of particles and is usually considered a 90-day filter.

MERV 14-16—These high-efficiency air filters are sometimes referred to as media filters. They can be four to six inches thick. They trap much smaller particles, but they do restrict airflow so do not use these high efficiency filters unless your HVAC maintenance provider specifically says they are right for your system.

MERV 17-20—Also called HEPA filters, these can trap nearly 98% of all particulates. While there are some modern residential heating & cooling systems using HEPA filtration, they are more common for commercial use. HEPA air filters restrict airflow so much it can severely damage your furnace or air conditioner.

Depend on Kotz for your filter needs

Kotz technicians will ALWAYS check the filter during regular HVAC maintenance. While most homeowners handle air filter changes, we will always ask you when it was last changed and replace the filter if needed. Here’s to hoping this helped take the mystery out of air filters and explained why they are a key part of HVAC maintenance in your Waterford, MI home. For more great information like this be sure to like and follow us on Facebook and Twitter.