Heating and Air Conditioning

How to Pick the Best Filter for Your HVAC Unit

Written by Whitney Bennett

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You've most likely heard time and time again that you have to replace your furnace’s filter every month. But, did you know that there are filters that are so effective you don’t have to replace them for up to a year? The truth is, not all HVAC filters are created equal. Depending on the specifications of your HVAC system and your personal air quality preferences, you have many different options for filters.

Home Warranties and HVAC Filters

You may be asking yourself, what does a home warranty company know about HVAC filters? Landmark’s home warranty coverage repairs and replaces HVAC systems as long as they have been properly maintained. An HVAC system's filters should be replaced at least once every three months when in use.  When the filter isn’t replaced monthly, or at least every three months, it makes the furnace or air conditioner work harder to heat the air inside of a house, and will most likely cause the HVAC unit to break down faster. If a home warranty company’s contractor sees that the owner has neglected to change the furnace filter and it caused the furnace to break down, the home warranty company may not cover the repair.

What Are the Different HVAC Filters?

A filter is your HVAC system’s first line of defense of making sure the air quality inside of your home isn't full of dirt and dust, and to protect the internal components of the HVAC unit are clean and working properly. Most HVAC units are forced air systems; they literally force air through a filter and into the rest of your house to cool or heat the rooms within. The filter traps dust, pollen and germs before they’re blown throughout the house.

Some filters are better at trapping dirt and pollen, while some don't trap as much and let your furnace work more efficiently, lowering your bills. It can be hard to choose which air filter is best for you, especially when there are so many different options. Here are a few tips to get you started on buying the correct filter.

MERV Ratings for HVAC Filters

As you begin looking at filters, you may notice a MERV standard on many of them. The MERV (Minimum Efficiency Reporting Value) tells you how much dust and contaminants can pass through the filter. Filters with a higher MERV allow less particles through them. However, this is a double edged sword. Although less particles are passing through the filter, your HVAC system has to work harder to force air through the filter and into the house. Using a filter that has a higher MERV standard than is recommended by the manufacturer can be detrimental to a furnace and a home warranty company will be less likely to pay to repair and replace it.

The MERV rating was created by the American Society of Heating, Refrigerating and Air- Conditioning Engineers and the scale goes from 1 to 20. The rating is based on the size of particles that can get through the filter. ASHRAE tests filters for particles like pollen, dust, dust mites, and smoke when determining each filter's MERV rating. A filter with a 4 on the MERV scale will filter out things like dust, pollen, moss, paint and fibers, while an 8 will filter out mold spores, dust mites and pet dander. The highest MERV (20) will filter out viruses, carbon dust, and smoke. (Usually, these are used for hospitals or clean rooms.) The United States Environmental Protection Agency says filters should be at least MERV 8 to meet indoor air quality specifications.

Manufacture’s Specifications for HVAC Filters and MERV Ratings

The very first thing to look at when purchasing a new filter for your HVAC system is the size of filter. Buying a filter that is “close enough” to what your system needs will let dirt and dust escape into the air vents through holes and gaps between the air duct and filter.

Next, make sure that the filter is at the specified MERV standard. If you want to buy a higher MERV filter than what the manufacturer recommends, you will run the risk of burning out your blower and heat exchanger on your HVAC unit. A home warranty company usually only repairs and replaces an HVAC unit if the unit has a filter that has the proper MERV standard.

MERV Ratings for Different HVAC Filters

Once you know the highest MERV level your furnace can handle, it’s time to pick out the best filter for you and your home. Here are the options:

Washable Filter

MERV rating: 1-3

This first HVAC filter is made up of a wire-like mesh. A home warranty company will repair or replace the furnace if it breaks down as long as this filter has been cleaned every month. It doesn’t bump your gas or electric bill up because air flows freely through the mesh, but it also doesn’t clean the air as well as other filter options.

Fiberglass Filter

MERV rating: 3-4

This filter usually goes for less than a dollar. According to many home warranty companies, furnaces that use this type of filter need to be changed out every month for proper maintenance. They will trap pollen, dust mites, dust, paint spray, lint and textile fibers. It’s not going to clean your air well, but it’s cheap, and it won’t increase your gas or electric bill.

Pleated Filter

MERV rating: 6-10

This filter is made from cotton fibers that are pleated, increasing the surface area of the filter, which traps more contaminants. They cost between 10 and 50 dollars. It will trap larger micron particles like dust and lint, but it will also trap bacteria and mold spores and, depending on how thick the pleats are, smoke. Although many home warranty companies ask for owners to use this type of filter, they must remember to change them out every month.

Electronic Media Filters

MERV rating 8-16

This filter is usually purchased with a new furnace or as an addition to an older furnace. The filters themselves range in price, but the actual electronic filter casing must be installed before purchasing an electronic media filter. The initial price to put in an electronic filter can be hefty, but it’s perfect for individuals who won’t change their filters once a month as recommended because they can be changed yearly. These filters have 2-3 inch deep pleats and trap smoke, dust, pollen, and microbes through electronic fibers that attract and trap particles. Many property managers feel it’s a better deal to purchase an electronic media filter rather than going into the rental home every month and replacing the filter.

There is one other type of filter (a high-efficiency pleated with a MERV of 14-20) but most home’s furnaces cannot handle blowing air through this filter. As a home warranty company, unless you have the proper furnace, this home warranty company advises not using this type of filter as it will cause early burn out. These filters are usually only used for clean rooms and hospitals.

If you take great care of your HVAC unit but know it will eventually fail, as all HVAC units do, consider investing in a home warranty to protect it. A Landmark Home Warranty helps you repair or replace failed systems and appliances when they stop working for a flat rate service call fee. Learn more by comparing the home warranty plans Landmark offers and learning more about why choosing Landmark as your home warranty company is a smart choice.

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