What is The Ideal Time Interval For HVAC Filter Replacement?

Learn about the ideal time interval for HVAC filter replacement. Find information on HVAC filters, AC filters, and when to replace them. Visit Sandium for guidance now!

Updated on Oct 23, 2023
5 min read
What is The Ideal Time Interval For HVAC Filter Replacement?

Air filters in your Northern California HVAC system is one of the most important components. Air filters need to be clean if you want the system to work optimally and efficiently. The condition of your air filters plays an important role on your health as well. Most people believe that air conditioning filters need to be changed every 30 days. But, is that right? Keep reading to know more.

Changing Air Filters in 30 Days

The instructions on the standard fiberglass filters (one inch) for HVAC systems state that they need to be replaced every 30 days. Several organizations and HVAC contractors repeat this advice dutifully. The truth is, changing your air filter every month is not going to cause any problems. I fact, it may just prevent some troubles.Low air is a major problem that is experienced by most homeowners. Changing air filters periodically can prevent this from happening. However, 30-day filter replacements can be hassling. The good news is that you won’t need frequent changes in spring and fall since there is not much need for cooling or heating during these seasons.

In addition, houses that don’t have duct leakage, infiltration or generally have a low level of overall dust don’t need frequent changes. Air filters tend to stay cleaner for longer in these homes unless the return vents are on the floor.

Filter Type Plays a Major Role

If you are conscious about the air quality in your home, you know that high-MERV air filters are the best kind. Homes that are in need of better filtration require at least a MERV-13 filter. However, the higher you go on the MERV scale, the more expensive air filters get. You may not find it lucrative to change the air filter every 30 days in this case.

Luckily, high-MERV air filters tend to hold more dust and dirt as compared to regular filters. They have thicker, pleated filters with more surface area. There is lower pressure drop even when the filters accumulate as much dust as the standards 1-inch filter.

Understanding Total System Pressure

Air filters need to be designed properly if you want the pressure drop to double across the filter. You would also require a duct system that works effectively and does not have excessive air flow resistance. You cannot let the pressure drop on a MERV-13 air filter load to the point of 0.5 i.w.c. if the pressure drop on a clean, brand new filter is 0.25 i.w.c.This would cause the pressure drop on the dirty filter to be equal to the total external static pressure. In layman’s terms, it means that the air filter has used up all available pressure throughout the whole duct system. In case of a furnace system, the air filter would have used up all the pressure within the air conditioner coil.

You need to ensure the filter design and duct system are appropriate if you want to decide using the performance-based method. You should think about fixing those problems so that the only thing signaling air filter change is a pressure drop.

Changing air filters on time is one of the most vital tasks in maintaining an HVAC system.

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