4 Questions About Furnace & Central AC Filters

September 5th, 2020

Cosmo again! Here’s a question for you: when was the last time you replaced your central AC or furnace’s filters? Have you looked at them in the past few months, or even thought about them lately? If not, take a look at them now. Do they look dirty? If so, that means they’ve been doing their job, but it also means it’s time to replace them!

Filters are essential components of furnaces and AC systems. Unlike other types of maintenance that should be done by professionals, filter replacements are a task you should handle yourself. Although no one likes adding yet another item to their to-do list, replacing your filters is a simple but important task with major benefits.

Filters help keep your HVAC system clean and improve Indoor Air Quality (IAQ). Dirty filters can cause your AC system to freeze, and your furnace to overheat! Either one could mean a costly HVAC repair, which, in Mercer County, NJ means it’s time to call SG Heating & Air Conditioning LLC!

Filter replacements for your HVAC system are like oil changes for your car, and like the old adage “Pay me now, or you’ll pay me later,” it’s a task you should perform regularly to avoid big problems later on. Changing your filters keeps your air cleaner, reduces airborne allergens, and will save you money in the long run.

Question 1: What’s the purpose of Furnace and AC filters?

After your HVAC system heats or cools the air, it brings this conditioned air back to the furnace or air conditioner. This return air will can then be heated or cooled and again, but before it can be distributed throughout your home, contaminants need to be removed. That’s why filters are necessary. Not only do they make the air safer to breathe, but they also help protect the system’s blower fan and AC coil from hair, dust, and other contaminants that the return duct sucks in.

Heating and Air Conditioning units that have their filters replaced regularly are less likely to experience problems or require costly repairs. Another huge positive associated with new air filters is the improvement of your Princeton home’s Indoor Air Quality. You have very little control over what the air is going to be like outside, but if you have a well-maintained HVAC unit, you can reduce irritants like dust and pollen and make sure the air in your home stays fresh.

Question 2: How do I choose the best filter for my Furnace or AC?

Filters are classified by Minimum Efficiency Reporting Value (MERV) ratings: the higher the rating, the higher its filtration capacity. There’s a caveat though – the higher the MERV rating, the more resistance to airflow. If your system and its attached ductwork have high static pressure, adding a filter with too high a MERV rating can cause system problems or damage. For new systems, SG Heating & Air Conditioning typically installs MERV-11, but your home may require a higher or lower rating depending on your exact needs. Other types of Indoor Air Quality products are available, like Photocatalytic Systems that actively kill mold, mildew, bacteria, viruses, and volatile organic compounds (VOC’s). The goal is to filter out or oxidize most pollutants without lowering the efficiency of the HVAC system’s performance. Installing a filter with a MERV rating that’s too high can do more harm than good, decreasing airflow and increasing static pressure. On the other hand, a MERV rating that’s too low will allow the system to get dirtier faster, also something you want to avoid. We’ll advise you as to the best type of filter for the system, and you can also ask your technician during your Heating or Cooling Precision Tune-Up to check and advise you as to the proper filter and possible upgrades.

Question 3: How often should I replace my Furnace or AC filter?

The short answer: more often than you might think! Check your filters monthly, and change them when they’re visibly dirty. 1″ filters should be changed at least once every 3 months, while 2″-6″ conventional filters should be changed at least once every 6 months. An easy way to get into this routine is to buy several filters for the year and label them by month. That way, you’ll never fall behind schedule when it comes to improving your AC or furnace’s lifespan and efficiency!

An important note: Filters are directional! Printed on the side of most disposable filters is an arrow. That arrow should be pointed at the equipment. The filter has support of the outlet side, and installing it incorrectly can cause it to fail. If you realize your filter is installed the wrong way, don’t turn it around, because if you do, the dirt already captured will be blown into the system. Instead, replace it or wait till the next filter change.

Question 4: Should I cut my filter if it’s too large for my Furnace or AC?

No. For optimal filtration, use a filter that’s designed to fit your unit’s exact size. Resizing a filter to fit the space is not a good idea – doing so can create a gap that lets particles get through that should be getting filtered out. Each of the four sides of the filter is designed to fit snugly next to the duct, allowing no particles to get around the filter. Cutting one or more sides will allow particles to pass through, and can also cause the filter to get loose, which can cause it to get sucked into the equipment!

Our HVAC maintenance agreement customers enjoy the convenience of having our skilled technicians out once or twice a year to check and replace their filters and service their equipment. But remember, 1″ filters should be replaced at least four times a year, not just once or twice a year, so this is still going to be a do-it-yourself job some of the time.

Still have questions about your heating and cooling system’s filters? Fill out our contact form, or call us at 609-448-1273 to learn more about what you can do to take care of your HVAC system, and what we can do to help.

There you have it, folks. The UNFILTERED truth! Woof!