Maintaining Your Furnace Filter

Maintaining Your Furnace Filter

The first step in checking furnace filter is to check and make sure your filter is properly sized for your furnace. Ensure that the filter completely fills the holding area, with no gaps at top, bottom or sides. Also the filter should be thick enough to seal off any avenues for air to bypass the filter. You can typically look at the filter in place by removing bottom panel of furnace. This should only be done once power is shut off. Newer furnaces have a safety switch on their fan compartments but turning power off is always advised.

Another item to check is your owner’s manual for the furnace and check that you have the right style of filter for your furnace. Some people buy universal re-usable filters that might provide too much resistance for the modern high-efficiency furnaces used today. If no manual is available check on the internet for manufactures site and look up specifications for model of furnace you have. If no specifications are available, send them an email, most companies gladly provide information on requests from customers.

Most furnace technicians will recommend that you clean or replace your disposable furnace filter periodically and during high use seasons, check your filter monthly. If you have pets your furnace filter may require changing more frequently. Your annual furnace maintenance should include brushing and vacuuming  the heat exchanger surfaces every year, or more if recommended by your owner’s manual. Before the heating season, clean the blower blades and seal any air leaks in ducts with metallic duct tape.

Types of Filters

Pleated – Experts typically recommend this type of filter as a bare minimum requirement. Pleated filters should also include the metal wire to perform electrostatic dust control. The pleat feature allows greater filtration because of greater surface area which creates less air restriction.
Disposable fiberglass filters – These filter are the least expensive – and also the least effective, designed to block only large dust and dirt particles to protect your furnace. Smaller particles, like pollen and mold, pass right through.
Electronic air cleaners Electronic air cleaners are expensive but are the best at removing harmful particles and pollutants from the air. In many cases, the initial cost can be offset with lower medical bills for allergy suffers.

Filter Ratings

What is an efficiency or MERV rating?

Most filters are labeled with a MERV (Minimum Efficiency Reporting Value) rating number, which measures a filter’s ability to trap particles ranging in size from 3.0 microns to 10.0 microns. This number is derived from a test method designed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) and is intended to help people compare filters.
Residential filters commonly have MERV ratings of 1-11. The higher the MERV rating, the more efficient the filter is, and the more particles it can filter.

A MERV rating of 6 means the filter is 35% to 50% minimum efficient at capturing particles, sized 3.0-10.0 microns.
A MERV rating of 8 means the filter is 70% to 85% minimum efficient at capturing particles, sized 3.0-10.0 microns.
A MERV rating of 11 means the filter is 85% to 95% minimum efficient at capturing particles, sized 3.0-10.0 microns.
MERV is an industry standard rating, so it can be used to compare filters made by different companies.

Having your furnace inspected and maintained by a furnace technician once a year goes a long way toward keeping your forced-air equipment working properly. Start by cleaning or replacing the filter. With forced-air furnace systems, air returning to the furnace’s blower first passes through an air filter designed to trap dust and debris and will help clean the air passing through the filter.  The type and size of filter will determine how much is trapped before recycling through your home. On new homes, check all your ducts by removing grills and vacuuming any debris that you can reach. If extremely dirty, notify the builder and have him clean the ducts. This is only possible on new construction and ducts should be inspected on your Pre-Delivery Inspection.

When furnace filters become blocked with debris, they cut down on a furnace’s efficiency and, over time, can cause parts such as blower motor, to wear out faster. Change filters quarterly or sooner if they look dirty. Pleated fabric filters are a good, inexpensive choice for reducing dust and allergens. Most experts recommend a pleated filter with wire for electrostatic performance. If you buy filters that are 3 for $10.00 then you probably could read a book looking through them, so you can imagine how useful they would be. Also check your manufactures recommendations before installing a washable filter, some type restrict too much air on high-efficiency furnaces and may cause premature failure of fan motor.

Steps to changing your furnace filter:

1) As with any electrical device you should turn off the power to the unit prior to doing any maintenance. Every furnace is required to have shut off switch designed for this use.
2) Look for the door or panel that conceals the blower; sometimes this is marked “Filter.” Lift this door or panel off of its holding hooks or unscrew its retaining screws to remove it. Some furnaces have a custom sized filter which is held in place by wire screen in bottom compartment of furnace.  Removing this panel will kill power to furnace if you have forgot to turn on main switch.

3) Newer furnaces have the filter installed on exterior of furnace on supply side. A good installation will have a metal cover over side of filter to prevent air leakage. Remove cover and slide the filter out along its tracks. Check to see whether it is a disposable filter or intended to be cleaned and replaced–this should be marked on the filter’s edge, along with directions for cleaning if applicable. If it’s a disposable filter, its size will probably be printed on the frame’s edge also. Make a note of its size.

4) Buy a replacement and slide it back into place, noting that arrows stamped on the side indicate the proper direction of airflow; be sure you face these in the proper direction. If your smoke detectors or carbon-monoxide detectors start going off after cleaning your filter, you have installed the filter facing the wrong direction. Remove and reverse filter, this will resolve your detector alarm problem.  Older furnaces will have filter mounted inside blower cabinet and be held in place with spring type assembly.

If someone in your family has allergies and you move to a new home that had pets living in it, cleaning your ducts might be advisable to remove build up which will then allow your filter to perform to its optimum ability. The most recommended type of duct cleaning is with brushes, which are sized according to the duct they are cleaning. This will allow filter to prevent dust and particles from circulating in your home.

Be the first to comment

Leave a Reply