When you purchase an HVAC filter, you must understand the difference between the nominal size and the actual sizes of the filter. HVAC filter manufacturers use the nominal size to label the boxes in which the filters is sold. The nominal size of the filter is a rounded number that is easier for a person to categorize.
The actual size of the HVAC filter is usually a half inch smaller on each side than the nominal size listed on the box. The half-inch allowance allow the HVAC filter to slide into the tracks of the HVAC system. Measuring the dimension of your old HVAC filter to find the replacement will not work because searching for the actual dimensions of your HVAC filter will not reveal the nominal labels of the filter.
How to Choose and Care for HVAC Filters
You must search for the nominal label of the HVAC filter in order for the HVAC filter to appropriately fit into the slot within the HVAC system. If the HVAC filter that is purchased is too large for the slot created in the HVAC system, the media of the HVAC filter will be crushed. A crushed HVAC filter will not be able to catch all of the particle in the air that the HVAC system must filter.
If the HVAC filter that is purchased is too small for the slot within the HVAC system, dirty air will be allowed to pass through the HVAC system. Another factor that you must consider when purchasing an HVAC filter is the filtration rating of the filter. Not all HVAC systems use the same filtration rating for there filters.
People use the MERV scale for HVAC systems in the home. Standalone air purifiers use the HEPA scale to rate the filtration capability of their filters. The most common HVAC filtration rating is the MERV 13 rating because it will catch most of the fine particulate in the air without obstructing the HVAC system’s motor.
Using a MERV rating that is too high for the HVAC system can create a pressure drop in the system. When the air cannot move through the HVAC filter easy, the furnace motor has to work harder to move that air through the HVAC system. If the furnace motor works harder at moving the air through the HVAC system, the energy bills for the home will increase.
Additionally, if the motor works so hard to move the air through the HVAC system, the motor can burn out. Deep pleated filters are a different category of HVAC filters. These filters are used for individuals who has very dusty environments in their homes.
Deep pleated filters allow for more surface area to trap the dust in the air. Because these filters are thicker than other HVAC filters, more air can flow through the deep pleated filters even if they are filled with dust and debris. Additionally, because deep pleated filters have more surface area to trap the dust, these filters do not need to be changed as often as other, thinner HVAC filters.
The downside to using deep pleated filters is that you must purchase a dedicated media cabinet for these filters. The media cabinet will allow the deep pleated filters to run for a longer period. When you purchase a portable air purifier, you will find that the device will display the Clean Air Delivery Rate (CADR) of the air purifier.
The CADR will let you know how much clean air the device can move into the room in which the device is to be used. Choose a CADR that will allow the air in your room to be cycled through the air purifier several times per hour. If you or your household member have severe allergies, you will need to purchase an air purifier with a higher CADR than if someone in the household is healthy.
If the air purifier is too small for the room that the air purifier is to clean, it will only clean a small area in the room. It will not be able to clean the entire room. In order for your HVAC system to work efficient, you must maintain the HVAC filter according to a regular schedule.
If the filter is clogged with all of the dust in the air, it will create problems for the HVAC system. If the HVAC system works harder to push the air through the clogged filter, the blower motor has to work harder to move the air. This increased static pressure within the HVAC system can make the HVAC motor use more electricity.
You should check prefilters and carbon filters according to a set schedule within your HVAC system. Carbon filters are challenging to maintain because they can become filled with the odors of the substances in the air without visibly showing the amount of dirt in the filter. Eventually, when a carbon filter becomes filled with these odor-causing substance, the filter will stop working entirely.
Lastly, you must never wash a True HEPA filter with water. True HEPA filters have fibers that are woven together in such a manner that when the air passes through the filter, the woven fibers trap the particles in the air. Water will destroy that web of fiber if you rinse the True HEPA filter with water.
It may look clean when rinsed, but the structural parts of the HEPA filter have been destroyed. If the structural parts of a True HEPA filter are destroyed, it will no longer be able to catch the small particles that pass through the filter.