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Furnace Maintenance: What Do Filter Arrows Indicate?


If you've never changed your furnace filter (which is the same as your air conditioner filter), you might need someone to show you how the first time. It can be a bit confusing to know which way to put the filter in -- do those arrows mean they should point upward or downward? Furthermore, filters can sometimes be hard to access in that they're located in hard-to-reach places.

But unless you have some kind of limited mobility issue, most of us just go ahead and change the filters ourselves. And if no one is changing it regularly, it's time to get with the program and make sure this task is performed on a regular basis. Following are some furnace (and A/C) basics to live by in your home.

Filter Basics

1. The furnace filter can be located in one of several places: in the ductwork, near the furnace, inside the air handler or in the furnace cabinet. If you're not sure, get your HVAC tech to show you.

2. Always buy the right size filter. Do not try to cut it down or cram the wrong size filter into the slot. It won't do the job properly.

3. Buy a better quality air filter. It will not only keep your HVAC's parts cleaner, but will also help clean your air. Look for denser, pleated filters, rated 8-12 on the Minimum Efficiency Reporting Value scale. Filters rated higher than this can slow air flow. In general, you will not need to change these filters as often as the cheap fiberglass types. Change these better quality filters every two to three months; make it every two months if you have shedding pets.

4. Point the arrows toward the furnace or air handler when you install the filter, making sure it's all the way in. It probably won't hurt your HVAC system to install the filter upside down once, but you certainly don't want to do this on a regular basis.

Visit the Valley Heating, Cooling, Electrical and Solar website for more on furnace filters and in-depth information on most HVAC topics, or call (408) 868-5500.

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