Many homeowners take residential air filters for granted, not realizing the essential role they play in the forced-air heating and cooling process. They not only clean the air as it passes through your HVAC system; they also keep dirt and dust from contaminating sensitive heating and cooling equipment.
A wide range of furnace or AC filter sizes, shapes and efficiency levels are available for homeowners. The paperwork with your central heating or cooling system should recommend the correct type of filter to use. In households without serious dust or other air-quality issues, a medium-efficiency filter purchased at a home improvement store or heating and cooling business for under $15 should work fine. Without expert consultation, however, don’t buy an extremely high-efficiency filter. These employ dense filtration media that can impede system airflow, which hurts operational efficiency and performance, and can damage the equipment.
Make Sure Your Home Air Filter Is Clean
If your home air filter gets clogged with dust or debris, it can’t do its job properly. This can cause these two problems:
• When an AC or furnace air filter gets clogged, it can’t let as much air through. A forced-air HVAC system absolutely depends on a smooth flow of air into the equipment, and then through ducts and registers into the rooms of your home. If airflow is restricted, heating and cooling will be uneven and take longer. Some parts of your home may stay uncomfortable. Plus your equipment will work harder to meet temperature demands, resulting in wasted energy, stress on parts and eventual breakdowns. In most homes, the HVAC equipment is carefully sized based on a specified airflow. If the airflow is restricted, you won’t get consistent or efficient heating and cooling.
• When the furnace or AC filter is clogged, dust and dirt particles will fall into sensitive equipment such as the blower motor. This increases friction and reduces efficiency, wasting energy and impairing performance. It may also lead to breakdowns in the equipment or even a shortened service life. Keeping a fresh filter in your HVAC system can save you from unnecessary AC and heater repairs.
Residential Air Filters Are Simple to Replace
In most households, the air filter slot in the forced-air HVAC system is easy to find. The process of replacing an old filter is as simple as sliding it out of the slot and sliding a new one back in. In systems that require a more involved process, the equipment manual should have that information. Take a moment to write down the date of the new filter installation on the side of the filter. That way, you won’t lose track of when you last replaced it.
In some homes, air quality challenges are so serious that an air filter can’t be expected to address those issues. If that’s the situation in your home, discuss other options with your trusted HVAC contractor. A variety of air cleaning and purification systems are available, some of them that work with your central heating and cooling system, some of them that don’t. In many homes, the air quality problem may be confined to one or two rooms; in those cases, plenty of portable or room air-cleaning options are available.
Permanent or Replaceable
Air filters come in a variety of types and quality levels, though the first distinction to understand is that they can either be disposable or permanent. As the names suggest, the former should be replaced periodically (monthly is the standard frequency, though that’s variable depending on the season and/or how much the forced-air system is being used). Permanent filters will work five to 10 years, though they need to be cleaned regularly. Some come with a lifetime guarantee. Permanent filters typically are more expensive to purchase than replaceable filters, though over time they cost less since they don’t need to be replaced.
Five Types of Filters
As for other differences in filters, they come in five basic types – fiberglass, pleated, electrostatic, carbon and HEPA. Here’s a quick rundown of each type…
Fiberglass filters: The cheapest available filters, these are made from spun fiberglass. They don’t provide much air resistance, which is good for system airflow. However, they don’t capture a very high percentage of airborne particulates. If indoor air quality isn’t high on your priority list, this may be the way to go.
Pleated filters: The pleats for which these filters are named provide more surface area for capturing airborne particulates. They’re typically made from tightly woven cotton or polyester. Most often, they come in mid-efficiency levels (6-12 on the MERV scale), with the efficiency determined by how tightly they’re woven. The models with higher efficiency may be designed to target pet dander, mold spores and allergens. These are more expensive than fiberglass filters – usually around $10 to $15 – but don’t need to be switched out as often.
Electrostatic filters: These come as either permanent/washable or disposable. Disposable electrostatic filters are usually pleated. These filters electrostatically charge airborne particulates and then absorb them into the filter like a magnet. Some experts aren’t convinced on the effectiveness of electrostatic filters, though others swear by them. They generally boast a similar range of MERV ratings to pleated filters.
Carbon filters: These filters use carbon or charcoal to filter the air, and are especially effective at trapping gases. The molecules of contaminants attach to the carbon molecules. When carbon filters reach their maximum efficiency, they stop attracting pollutant molecules and may even start releasing them (it’s more technical than that, but that’s the simple explanation). One disadvantage of carbon filters is that it may not be clear when the filter needs to be replaced. In general, thicker carbon filters will work better to clean the air than thinner filters. Another characteristic to be aware of is that carbon filters are good at some things (filtering out volatile organic compounds/VOCs, cigarette smoke, fumes from solvents and cleaning fluids, etc.) and not so good at removing others (dust particles, pet hair and dander, etc.).
HEPA filters: HEPA stands for High-Efficiency Particulate Air (or Arresting). A true HEPA filter boasts the highest MERV rating – between 17 and 20. However, HEPA filters are so dense that they will impede airflow in a typical residential forced-air HVAC system (reducing efficiency and potentially causing breakdowns), unless expensive modifications are made to the system. If you’re very concerned about indoor air quality, it’s probably a better bet to invest in a dedicated air-cleaning system that won’t restrict airflow in your heating and cooling equipment.
If you’d like professional guidance, discuss your air filter situation with a trusted local HVAC contractor. Our technicians at Jansen Heating & Cooling will tell you which filter will work the best with your particular forced-air heating and cooling system. Once you’ve made your decision, save yourself some time and money by purchasing the selected filters in bulk. If you decide to buy them one at a time, once every month or so, you’ll probably end up leaving them in place longer than necessary, just through procrastination.