All About Furnace Filters

October 23, 2019

A furnace is arguably a home’s most stalwart workhorse but many people don’t pay it much attention. Just like turning on the faucet and expecting water to come out; as long as a furnace keeps the house at a comfy temperature, everyone’s happy.

But you need to give your furnace some love for it to return the favor, and that means changing its filter regularly.  Sounds easy enough to do but it is also easy to neglect.  Filters are the lungs of a furnace and if you let them get dirty or in disrepair, the whole system breaks down.

What is a furnace filter?

Traditional furnace systems draw air in through ducts, warm it over a heat exchanger, and push heated air throughout the house. A furnace filter’s job is to protect the blower fan from Sahara-like dust clouds constantly circulating in from the ducts. The filter also keeps contaminants from being recirculated around the house.

What are furnace filters made of?

Most common furnace filters are made of paper and polyester, as well as fiberglass. The paper versions are usually pleated and filer most household particles and allergens. Fiberglass filters are generally flimsier and rated at lower efficiencies.

Where are furnace filters located?

In most cases, furnace filters are located inside the blower compartment, near the fan. They are found behind panels, inside duct openings, or behind other internal equipment.

How many filters does a typical household use in a year and how often should they be changed?

All furnace filter types have specific recommendations for when they should be changed. Some are reusable and only require cleaning, while others must be replaced. General guidelines call for filters to be replaced every 3-6 months. Thicker filters last longer but most households will use 3-4 filters each year.

How long do furnace filters last?

Furnace filter lifespans vary depending on the type used along with the indoor air quality. Thinner, 1 to 2-inch filters can last up to 90 days. Four- to six-inch filters should be replaced every 6 months. Pets, dusty environments, and similar factors may require more frequent replacement.

Why is my furnace filter black?

A black furnace filter is a bad thing. The black gunk is soot build-up and in addition to dirtying your home, the soot can cause serious respiratory problems. Black filters are typically caused by a poorly burning furnace, improperly vented gas fireplaces, burning scented candles, and related issues that lead to soot collecting on and clogging the filter.

What kind of furnace filter should I use?

The user manual for your furnace likely indicates the type of filter to use. If you can find the manual, great; otherwise remove the existing filter. The type and size will be shown on the label.

If your furnace is having issues and not heating well, give the professional HVAC experts at Rowland Air a call for furnace maintenance and repair services.