High Efficiency Pleated
Generally chosen by most homeowners. They are available in an array of sizes, as well as MERV ratings. Pleated filters are made with synthetic material, eliminating moisture buildup and the growth of mold. They perform very well, filtering out household allergens and particles. The pleats are evenly spaced to provide efficient airflow. The pleat material is fixed to a rigid grid to keep the pleats in place and provide good durability. The price of pleated filters varies, depending on size, brand and rating. They should be checked monthly for any blockages and replaced every 90 days. They are economical and can be manufactured from green materials. A good choice for those who have respiratory problems or looking for overall improved indoor air.
These are the least expensive filters available. They have a "spider-web" like appearance and are typically blue in color. Available in an array of standard sizes and are more delicate, as well as having a lower merv rating than pleated filters. These disposable filters must be frequently checked and often need to be changed monthly.
Washable filters are made with either a plastic, or aluminum frame. They can be vacuumed and spray cleaned with water. Available in multiple sizes, as well as different MERV ratings. They're more expensive, but can last up to five years, which would make them a good economical solution. Proper maintenance is required and they should be cleaned every 90 days. The only negative is that you do actually have to clean them and many people either forget to do so, or simply don't want to.
This type of filter has electrically charged fibers that catch contaminants as they pass through the media. Great for homes that have pets or tobacco smoke. Check your electrostatic furnace manual to make sure that your system is suitable to operate electrostatic filters safely.
These filters have self charging cotton fibers that attract particles. They have a detachable, machine washable filter that can be re-used for up to 8 years.
Common furnace filter sizes
Furnace filters are sized, based on depth (thickness), length and height. The most common sizes are 1 inch and 4 inch filters. Length and height combos range from 10x10 inches to 30x30 inches. The most common available sizes are 14 x 20 x 1, 16 x 20 x 1, 20 x 25 x 1 16 x 25 x 3 and 24 x 24 x 4. To determine the size of your furnace filter, remove and examine the existing one to be replaced, or refer to your furnace manual.