Furnace Filters That Come in Half Sizes

Panel Filters

• Panel filters are the most common type of filters installed in furnaces. These filters are usually made out of fiberglass. Their main function is to protect the fan and the heating coil of the furnace. They will remove hair and large particles of dirt from the air, but they don’t filter small particles. Panel filters are available as disposable or washable filters and cost less than any other type of furnace filter. They’re available in a range of thicknesses, including 1/2-inch.

Media Filters

• Media filters aren’t commonly used by most homeowners, but they can be a good choice for you if your furnace uses an odd-size filter since they’re available in every size, including 1/2-inch. Media filters are made out of synthetic materials such as polyester and are available either as precut pads or in bulk rolls. The rolls come in 100-foot lengths and are cut to fit an aluminum filter holding frame. Media filters have the ability to trap a large amount of dirt. They cost more than panel filters but are used by many heating, ventilation and air conditioning technicians because they’re reliable and cost-effective.

Electrostatic Filters

• Electrostatic filters use static electricity to remove dirt from the air. Reusable versions have filters that must be washed every few months. They are nonelectric. Electric versions have replaceable pads that must be changed every month or two. Electrostatic filters can remove more than 90 percent of particles in the air and they filter particles as small as 1 micron in size. These filters normally come in 1/2-inch and 1-inch sizes, but custom sizes are available, too.

Wrong Sizes

• Installing a filter that’s the wrong size for your furnace can damage it by causing leakage and allowing dirt into your blower fan. Using a filter that’s too small can cause it to be sucked into the blower fan, damaging the fan motor and perhaps causing a fire. Never stack filters in an attempt to increase the thickness of your filter because doing so will interfere with air flow and cause the blower on your furnace to overwork. If you can’t find a filter to fit your furnace, you will need to have one custom-made.