Improving energy costs

How can changing furnace filters save energy costs?

A significant purpose of a furnace filter is to remove airborne particles that might damage the furnace equipment. As the filter work, airborne particles build up on the filter restricting air flow making the furnace work harder to pull air through the intake (or return side), decreasing the efficiency of your furnace.

Minimum Efficiency Reporting Value (MERV) is a filter rating system to standardize and simplify air filter efficiency ratings for the consumer to allow them to effectively compare one unit to another. The higher the MERV rating - the higher the efficiency of the air filter. This simply means that a MERV 13 filter will remove smaller particles from the air than a MERV 8 filter. (Photo: Hugh Cairns)

Clean furnace filters allow for better air flow, increase the efficiency of your furnace and reducing energy costs, which in turn saves you money.

Furnace filter installation - How do I change my furnace filter?

Make sure that the furnace blower is off. You can do this by turning the furnace off at the thermostat. Alternatively, you can locate the emergency power shut off switch in the furnace area and turn it off. If you don’t shut the power off, removing the filter while the blower is on will result in disturbing the collected particulate and it will be blown into the furnace equipment. Locate the filter - usually located on the lower front or side of the furnace.

Hugh Cairns furnace filter tip - On some systems, you will need to remove a metal strip that covers the end of the filter. In some cases the filter is located in the furnace case - open the panel door to have a look. Slide the filter out, inspect and replace as necessary.

Furnace filter sizes - What size of furnace filter do I need?

Furnace filters come in various dimensions. If this is your first venture into replacing your filter you should make sure that the existing filter is the correct size. The size of the filter should match the filter slot. The size of the existing filter should be written on its edge. If it is not, measure it with a tape measure. Next measure the filter slot and compare the results, they should match. If they don’t, rely on the slot size.

When shopping for filters it is important to realize that the size written on the packaging may not be the actual size of the filter. Filters can be sized in two ways—nominal and actual. Nominal sizing is the approximate size of the filter, rounded up to the nearest whole inch. This makes filter sizes easier to identify when shopping. Also, air filters can also vary by thickness. Commonly they are one inch thick, and in some cases they can be more than 4 inches thick.

Furnace air filters should fit snuggly in their slot. Loose filters let air flow around them reducing filtration.

About the House – Furnace filter fact

48% of BC homeowners have forced air furnaces, of those:

  • 32% Changed or cleaned filter every three months
  • 24% Changed or cleaned filter every six months
  • 26% Changed or cleaned filter once in the past year

Source: Statistics Canada

For more tips on improving your indoor air quality with furnace filters, how often you should change your filters and the best kind to buy click here.

More About the House articles

About the Author

When you need advice or guidance with DIY home improvement and repairs, Hugh Cairns can help you with the answers.

Home improvements can be rewarding, turn your home into a nicer more comfortable place to live, and increase its value.

Whether you are renovating your kitchen, converting a loft, giving a room a lick of paint or making improvements to your home’s energy efficiency, this column is here to guide you with useful information and key things to remember.

Do you have a renovation question or concern? Please feel free to send Hugh your questions. Contact him through www.subject2homeinspections.com

The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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