What is MERV Rating? | (The Complete Homeowners Guide to – Merv Rating for Air Filters)

What is MERV Rating?

The MERV rating on air filters is a number from 1-16 that was established to help consumers understand how good a particular air filter is at removing foreign airborne particles.

What are MERV ratings?

MERV is an acronym for Minimum Efficiency Reporting Values. This designation was derived by the American Society of Heating and Refrigerating and Air Conditioning Engineers, or ASHRAE, to help consumers compare the performance level of various air filters.

How do I find the MERV rating on filters.

There are two thicknesses for mechanical air filters that are used on most residential HVAC systems.
For both the 1” and 5” filters, MERV rating can typically be found on the narrow 1” or 5” edge of most residential filters. The MERV rating is also located on most filter packaging labels.

Highest and lowest MERV rating air filters

The MERV rating on air filters for residential HVAC systems range from 1-16. The higher the MERV rating, the smaller the particle it is able to trap and the better it is at removing them.
Click to see a detailed chart on Average Particle Size Efficiency in Microns.

5 benefits of a higher MERV rating on filters:

  • Less Dust
  • Less Pollen
  • Less Mold
  • Less Allergan
  • Better Quality Air

What MERV rating should I use?

If minimizing pollens, allergens, molds or dust is a priority, you’ll want to pay closer attention to the MERV rating on air filters you choose.

Many older systems still use 1” filters for removing contaminants from your home. Determining what MERV rating is best if this is the case may be more difficult since higher MERV rated 1” filters can also be highly restrictive to good airflow. In these cases you’re sometimes better off choosing a filter with a lower MERV rating that can compensate for this restriction.

For most 5” filters, if money’s not the main concern, you’re better off getting a MERV 16 since it provides the best indoor air quality and also helps to protect the internal workings of the furnace and AC coil.

So What is a HEPA filter?


HEPA or“High Efficiency Particulate Air” is an acronym for a pleated type of mechanical air filter. It was established by the U.S. Department of Energy.

Theoretically a HEPA air filter can remove up to 99.97% of pollen, mold, bacteria, dust or any other airborne particle the size of 0.3 microns.

Any particles larger than this will get trapped at an even higher efficiency. For reference sake 45-50 microns is the average size of human hair. The human eye can generally not see anything that’s smaller than 40 micron

What MERV rating is best?

Now that you have a better understanding of MERV vs HEPA, deciding what MERV rating is best for you should be a far less daunting task.

HEPA filters are generally used in hospital settings and have the highest MERV ratings of between 17-20.

For additional Indoor Air Quality (IAQ) details, see the US Environmental Protection Agency (EPA).

What size of AC do I need?

This guide will help you quickly determine what size AC would be perfect for your home.

How many tons of AC per square foot?

AC Size Chart

How do I calculate what size air conditioner I need?

The 5 Easy Steps

  • Enter your home’s square footage
  • Select geographic area
  • Choose the number of occupants living in your home
  • Enter number of windows
  • Select your home’s level of insulation

So, what size central AC do I need? = 3 (X) tons! (The answer here)

disclaimer- This tool is a great reference for what size air conditioning unit your home needs but always be sure to consult with an HVAC expert for more information prior to undergoing any heating or air conditioning projects.

What Size of AC do I need?

7 Factors to Consider

  • Square Footage of Home
  • Geographic Region
  • Occupants
  • Window Quantity / Type
  • Insulation (R-Value)
  • Sun Exposure
  • Ductwork Sizing
  • Square Footage of Home- The primary factor when determining what size air conditioning unit your home will require is the overall square footage of the space.(Although, not all square footage is created equal.)
    • Ceiling Height: 1200 square foot home with 8 foot ceilings throughout will require significantly less cooling capacity than a 1200 square foot home with 15 foot vaulted ceilings.
    • Building Materials: A 1200 square foot home that has all vinyl siding will require significantly more than a 1200 square foot all brick home.
  • Geographic Region– Areas of the country with long summer seasons will require more cooling, as do areas with a higher humidity.
  • Number of Occupants– Human beings create body heat. The more people you have inside any given space, the more cooling will be required to offset that additional heat. (Ref. stat for human heat)
    • 1 person = 600 btu (pick a ref to outlink to)
    • 2 person = 1200 btu
  • Window Quantity and Type– The total number of windows along with their R-Value will have a surprising effect on how much heat or cold they allow into the home.
    • Type of Windows- Single, Double, and Triple Pane
    • Glass Thickness
    • Material Type: Wood, Vinyl, and Aluminum
  • Insulation (R-Value)– There are many different types of insulations that each are assigned a different R Value.
    • Higher R-Value = More Effective Insulation
  • Sun Exposure– The total amount of time your home is exposed to or shaded from direct sun exposure also has an impact on the overall cooling capacity needed.
  • Ductwork Sizing– Although sizing your equipment is important, it is equally important that your ductwork matches the capacity of your air conditioning system.
    Click for more information on Ductwork Sizing. (hyperlink to duct sizing page.)

It is extremely important to size your HVAC equipment properly to ensure it is capable of satisfying the heating and cooling needs of your specific home. HVAC Bee is providing this information as a quick reference guide for homeowners to gain a better understanding of those sizing requirements.

For more specific sizing information, consult your local HVAC Contractor to perform a detailed load calculation for your space.

The Complete Guide to Air Conditioning Refrigerants -| Freon in Air Conditioning (The Freon Ban)

Main Types of Air Conditioning Refrigerants

There are two main types of refrigerants used in residential air conditioning systems.

  • Freon” otherwise known as R22
  • Puron” which is also known as R-410A

The original Freon refrigerant has caused concern in the heating and air conditioning industry because it has proven chemical properties that make it harmful to the ozone layer. Freon was officially phased out as of January 1, 2020, meaning it is illegal to manufacture Freon in the United States.

The major benefit in converting to Puron since it is NOT as harmful to the ozone.

The Difference Between Puron and Freon in Air Conditioning

  • The disband Freon (R22) cooling agent can be referred to chemically as an (HCFC) or hydrochlorofluorocarbon or HCFC.
  • As for the new EPA approved Puron refrigerant, it can be referred to as or Hydrofluorocarbon or more commonly, HFC.

Did you catch the difference?

Why Puron in Air Conditioning? | (Approved Refrigerant)

The difference between HCFC and HFC is simply the removal of one ‘C’. It causes some confusion but just means the removal of one element, the chemical Chlorine.

This environmental impact, along with enforced government regulations, are why so many homeowners have already converted to the new Puron HFC coolant.

The United States Regulation of AC Freon | Banned Refrigerants – (The Freon Ban)

In 1987 the Montreal Protocol was introduced which regulated future production and importation of older style chlorine-based coolants into the United States market.

This regulation stated that,

“As of January 1, 2020, no new HCFC-22 will be made or imported into the United States, but used HCFC-22 will continue to be available.”

(United States EPA)


“People can continue to use air-conditioning (AC) equipment that operates on HCFC-22, EPA does not require homeowners to replace their existing equipment.”

(United States EPA)

This means that if you are already using the older style refrigerant, whether it is a window unit or central HVAC system, you’re not required by law to make any changes to your current equipment.

When to Update AC Refrigerant | (Replacing Freon)

Although you are not required by law to replace your existing system even if it operates on the older freon coolant, often times it can make sense to look into replacement anyways.

Top 3 Factors When Considering Replacing Freon for an Approved Refrigerant:

  • How does your system function currently?
  • Does your equipment need any major repair work?
  • Are you low on refrigerant and it needs a recharge?

Determining if switching makes sense for you really depends on whether or not your current system is still functioning properly, whether or not it needs any major repair work, and/or if your system needs a refrigerant recharge.

Cost Per Pound of Puron VS Freon in Air Conditioning?

The average price per pound of refrigerant can vary significantly by state and vendor but the general range in cost for a refrigerant recharge in 2020 is:

Cost of Freon per pound (R22) = The average pricing ranges from $40 to $180 per pound
Cost of Puron per pound = The average cost of puron refrigerant is $20 to $75 a pound.

The labor cost for a service tech to perform the recharge often outweighs the cost of the refrigerant and can drive the overall price.

Main Reasons for Replacing Freon

  • Large Impact on the Environment
  • Spike in Cost of Freon (Due to Freon Ban)
  • Higher Efficiency of New HVAC Equipment
  • Less Worry from Equipment Failure

The Freon ban has been a long time coming and for good reason. When you are considering whether or not to replace your existing heating and air equipment or continuing to recharge the system, it’s important to realize your overall impact on the world we all live in.

Since the supply for Freon has been completely cut off, the cost for recharging continues to skyrocket which can make switching to newer equipment a more economical choice.

With the 14 SEER Minimum Efficiency Standard (Ref to SEER Page) in place, replacing your older unit with new HVAC equipment can save you a bundle on your electric bill and alleviate the stress of continued system failure.

Contact Today to have your AC Coolant checked or updated with our ‘No-Sting Pricing.’