Date: 15/09/2019
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Selecting an Air Filter

When you go to a hardware or big box store to purchase air filters you will find a bewildering array of products. 3M, for example, offers 9 different types of filters each with different ratings and at a different price, and then each of those comes in different sizes. It can be confusing, to say the least!  We'll help you make sense of it all, so you can choose the best air filter for your needs.

Size Matters

Size is perhaps the easiest decision: get the size filter that fits the filter holder built into your HVAC system. It should fit snugly, with no air gaps around the filter. Be aware that filters come in thicknesses of 1-inch to 6- inches, with the thicker filters having greater capacity to catch dirt without increasing resistance to air flow and increasing the time between required filter changes.  However, you cannot put a thick filter (4 or 6 inches thick) into your HVAC system if it's designed to accommodate only a 1-inch thick filter.

Rating Matters

In our previous post, we talked about the MERV ratings of filters.  MERV is an industry standard measurement of filter efficiency.  Individual manufacturers often have their own rating system as well.  3M's rating is called MPR, which standard for Microparticle Performance Rating.  As with the MERV rating, higher MPR numbers mean a greater percentage of particles and smaller particle sizes will be captured by the filter.  

Price vs Performance

How do you decide which MERV rating to get?  Generally, the higher the MERV (or MPR) rating, the more expensive the filter.  For example, the price of a MERV 13 filter is about twice the price of a MERV 8 filter of the same size. 3M offers multiple filters having a MERV 12 rating, but with different MPR ratings, and so even among filters of the same size and MERV rating, the prices can vary.  Which filter to buy depends on how much cleaning you want your filter to do. The lowest price filters at MERV 5 will remove dust, debris and lint. This is the minimum needed to maintain the health of your HVAC system's heat exchanger and coils.  A MERV 11 filter removes smaller particles such as pollen, dust mites, mold spores, and pet dander. A MERV 12 or 13 filter can filter some bacteria, viruses, and odors.  Since the prices jump up dramatically at MERV ratings higher than 11, and the increased efficiency is only minimally incremental, using filters with more than a MERV 11 rating is probably not cost effective, unless there is some particular medical need.  In the chart, those shown in the "green zone" in the cost column represent the best value on a price vs. performance scale.



Important Tips & Advice



You often don't think about your heating or air-conditioning system until something goes wrong. But there is so much you can do to help keep your system from breaking down. We regularly post information to help you learn what you can do to keep your system running, to save money and energy.  Search our many posts, videos, and podcasts, for valuable information that is never a sales pitch. Subscribe to receive an email when something new is posted, so you won’t miss any important tips.

Choosing a Repair Company

Whether you’re talking about heating or cooling, repairing or replacing a system, you want a company that can advise you reliably based on what is in your best interest, not based on what is convenient or what earns them the most money (commissions). We'll help you choose the best solution to fit your needs. Check out our many posts at HVAC News You Can Use and our podcasts.

Going Green

We're concerned about the environment and know all the latest technologies - such as geothermal systems, LED lights, and smart thermostats - that can reduce energy and put more "green" in your pocket!  We've provided HVAC systems in certified LEED buildings and written many posts on ways to Go Green.

The Sign of Service

We are a repair company performing a full range of commercial and residential heating, air conditioning, energy management and comfort products service, maintenance, and installation. We are a locally-owned company serving Nashville-Davidson County and the surrounding counties including Williamson, Rutherford, Wilson, Sumner, Robertson, and Cheatham.

Who We Are

Our service technicians are fully trained and experienced.  We can tackle the most complicated system to the simplest of systems – from large commercial plants to single-family homes.  Our ownership group of Eddie Hutton, Tony Anderson, Roger Eldridge,  Swaney Powers and Alan Seilbeck have over 125 years combined experience as leaders in the HVAC industry.


We are proud of our dispatchers that respond to your telephone call. When your system is down they make things happen. Our trucks are loaded with most parts needed for a quick repair. You can call day and night 7 days a week. Our normal weekday hours are 7:00AM to 5:00PM. Click on the button below to schedule a service call online. Emails and forms can only be answered weekdays from 7-5.”  

615-832-8500 Online Service Call


Did you know you should service your HVAC on a regular schedule – just like you would your car?  We have specialized maintenance programs to ensure the clean, energy efficient and safe operation of your HVAC systems.  This helps minimize service interruptions/breakdowns and maximize your equipment's lifespan.  All maintenance contract customers are assigned a primary technician that will get to know your facility and equipment and will treat it like his own.  You’ll receive discounts on repairs or new installations, and get priority service when it is cold or hot outside and you need service promptly.  Plus, maintenance contract customers are never charged overtime rates for emergency services after-hours, weekends or holidays. We’ll teach you how to save on maintenance costs by showing you things you can do yourself and when you need a technician. Here are some good posts:  Repair vs. Replace, Things to Try Before Calling for Service, Springtime Tips that Pay Off.


Our team takes on HVAC projects for office, school, retail and industrial facilities. Check out these case studies:

Replacement of a 250-ton Cooling Tower

Ductless HVAC at Brentwood Middle School