Furnace Filters


Caring for your furnace is important, because you want it to function at its full potential for as long as possible. One of the best things you can do to protect your furnace, yourself, and your family is to regularly replace your filter. Here’s a quick guide to furnace filters our team created for you.

What Furnace Filters Do

The air inside your home has a lot of dust particles, dander, and other debris. This is where the air filter steps in. As your furnace circulates air, the air filter catches the dust and debris, stopping it in its tracks. This protects the parts in your furnace and improves the air you breathe.

How They Do It

Furnaces take in cold air through your ducts, convert it to hot air in the heat exchanger, and cycle it back out. Then the hot air pushes more cold air into the ducts, and the process repeats until your home is properly heated.

When the air gets cycled, it brings along many of the dust particles floating around in your house. The air filter catches these particles and lets the air pass through. The air that comes through is clean and is gentler on your equipment and lungs.

Choosing Your Filter

There are many different options for filters. When picking out your filter, be sure it fits the size your furnace requires.

Disposable (replaced monthly):

  • Fiberglass filters
  • These are the most common type of filter. They’re relatively inexpensive and readily disposable. They don’t catch smaller particles very effectively, so if you suffer from allergies or asthma, you may want to consider a different option.

  • Pleated filters
  • These are another commonly used option. They are typically constructed from polyester or cotton fibers, so they are capable of catching smaller particles. Though disposable, they’re more eco-friendly than their fiberglass competitors.

  • Electrostatic filters
  • These offer a more advanced and thorough cleaning process. When air passes through, the fibers naturally receive a static charge. This charge means dust particles are more attracted to it and end up sticking to it. These are extra tough on pet dander and cigarette smoke.

Permanent (cleaned regularly):

  • Reusable electrostatic filters
  • If you want all the benefits of an electrostatic filter but don’t want the hassle of replacing it, reusable electrostatic filters are a great option. Though more expensive than their replaceable version, the reusable electrostatic filter can last up to eight years. You can think of it as paying up front for eight years of protection instead of paying monthly (which may cost more in the long run).

  • High-efficiency pleated filters
  • These filters offer 4 to 5 inches of thick synthetic wool for extra protection. They are often used in hospitals, because they are the best filters for people with respiratory issues.

Check the MERV Rating

MERV (Minimum Efficiency Reporting Value) is an energy-efficiency rating system for filters and can typically be found on both the filter and its packaging. Its values range from 1 to 16, 1 being the least efficient and 16 being the most efficient. Generally, the thicker the filter is, the more efficient it is.

While you may be tempted to purchase the thickest filter possible, it may not be right for your furnace. Thick filters can actually hinder the airflow of some furnaces, causing them to perform less efficiently. Check with a technician to figure out which filter would best suit your air system.

When to Replace/Clean Your Filter

To protect yourself and your furnace, you have to keep your air filter clean. Most disposable air filters need to be replaced within one to three months. Check the manufacturer’s instructions for the correct protocol.

Reusable filters should be cleaned monthly in most cases. You should check them regularly for cleanliness, especially if you or someone living in your home has breathing troubles.

Western Sales and Services wants you to breathe easy! Please call our Birmingham, AL, office with any questions about air filters. Our number is 205-787-8674.

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