Before you choose the type of furnace filter to fit your needs, make sure you also have the right size of filter. The size of the filter you need can be determined by looking at the size of the filter already inside the furnace. This can give you the dimensions you will need. There are many standard sizes, but some furnaces will take a custom size. The best choice for these odd sizes is a washable filter you can cut to size.

There are four main types of furnace filter available on the market. They are: pleated, HEPA, electrostatic, and activated carbon. All of these types have specific features that help to trap dust and dirt from entering the air stream.

Furnace Filter Buying Guide

A pleated filter is one that provides additional surface area for the dust and dirt to collect on the filter. The filter is contained inside a cardboard frame for durability. Pleated filters can be large, so this may not be the best choice for smaller furnace units. Pleated filters are also available with an electrostatic charge.

An electrostatic filter is a type of filter that carries an electronic charge. This helps to attract particles to the filter. The electrostatic filter is one that made from materials that can be washed, so the filter can be used permanently with regular cleanings.

To help prevent allergies and other irritants from getting into the air, choose a HEPA filter. A HEPA filter is often used to purify the air to reduce allergens in the home. These filters are more common in vacuum cleaners and stand-along purifiers because some HEPA filters can hinder the amount of air flow through the system. These filters, however, are still available for furnace systems.

The last type of furnace filter is the type that uses activated carbon. The activated carbon works to absorb allergens like a HEPA filter, but activated carbon can also provide absorption of odors and hazardous chemicals in the air. Activated carbon filters are often used in factories and labs where many hazardous fumes may be present.

Remember that any furnace filter should be replaced or cleaned once a month to maintain a quality air flow.

One of the most important things to keep in mind is the specific size of the furnace filter. During time of purchase, it will be necessary to choose the correct size. Look for a number that is indicated by width, length and thickness. As an example, one of the most common furnace filter sizes is 16 x 25 x 1, although there may be others that are smaller or larger than this.

Replacing Furnace Filter

Types of Furnace Filters
The materials from which furnace filters are made are also fairly common:
1. Fiberglass
2. Electro-static synthetic fibers
3. Polypropylene

The types of furnace filters available range from the least expensive fiberglass filters to the most expensive which are a combination of an electrical air filtration and an air cleaner system.

Furnace Filters for Specific Needs
If allergies are a serious problem, furnace filters with the designation “HEPA”, are most effective in reducing dust and pollen in indoor air. There are other types of furnace filters that are designed with a 90% arrestance of irritating substances in air flow. Take note of the sizes of micron particles a furnace filter is designed to capture.

Installing a Furnace Filter
Installing a furnace filter is relatively simple. Do not attempt to replace or install a furnace filter without first turning the furnace blower to the “OFF” position. Check your Users Manual to locate the blower section of your furnace. In most cases, a slot is located between the blower and filter housing. Simply, slide the furnace filter in with the air flow arrow pointed in the designated direction on the furnace filter and replacement is complete.