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Top 10 AC Sins to Never Commit

Top 10 AC Sins to Never Commit

Summertime energy efficiency involves much more than choosing an energy-efficient central air conditioner. In fact, much of the benefit of a high-efficiency AC system can easily be negated by simple air conditioner mistakes such as the following:

  • Choosing the wrong system for your needs
  • Not understanding the importance of your AC air filter
  • Using the wrong air filter for your system
  • Ignoring air conditioner maintenance
  • Not doing regular AC troubleshooting
  • Procrastinating on AC repair
  • Using your system incorrectly
  • Not making sure your home is energy efficient
  • Not taking advantage of a few smart AC usage practices

The above air conditioner mistakes can prove costly — both to your comfort and your pocketbook — so it's always wise to learn everything you can about the smart ways to use your system for maximum comfort, effectiveness and savings.

The Central Air Conditioner: A Complex System

The central air conditioner is a complex piece of equipment. It takes HVAC professionals years of study and experience to master the intricacies of these systems, and even then, technicians must upgrade their skills periodically to keep up with evolving HVAC technology. That's why the average homeowner shouldn't feel bad to experience some difficulty grasping the many AC troubleshooting, repair, maintenance and other relevant principles that are important in preventing costly air conditioner mistakes. By educating yourself about the most important of these principles, you can increase your air conditioner IQ and use the lessons learned to significantly improve the level of efficiency you enjoy from your system.

The Benefits of Being "AC Savvy"

Here are several of the valuable benefits you'll enjoy once you know what not to do with your central air conditioner:

  • Consistently comfortable indoor temperatures
  • Effective humidity control
  • Better indoor air quality
  • Lower energy costs
  • Fewer repair bills
  • Longer AC system lifespan

The Top 10 AC Sins

By avoiding the following 10 common air conditioner mistakes, you can enjoy greater indoor comfort, lower AC repair bills and significantly reduced energy costs:

1. Buying the wrong AC system for your space

The right system type and size are both important to optimal system efficiency and effective indoor comfort. An HVAC expert can help you determine whether an air conditioner or heat pump system would work better in your climate. Your local HVAC specialist can also help you calculate the correct system capacity for the most effective cooling and dehumidification. A smaller system typically provides better dehumidification than an oversized one, since oversized systems may not run long enough to remove sufficient humidity from the air — particularly in humid climates. The smallest AC system that will adequately cool your space is generally best, though this can vary with heat pump systems.

2. Ignoring air conditioner maintenance

Your AC system works hard all summer to provide a cool, comfortable environment for you and your family. Over time, this day-to-day operation creates issues such as a dirty evaporator coil or a clogged condensate drain, to name just a few. Regular maintenance, though easy to ignore, is a must for efficient system operation and maximum indoor comfort. offers a list of helpful tips for Maintaining Your Air Conditioner. Scheduling an annual AC system check-up with you local HVAC specialist can give your system the once-over it needs to function efficiently all summer long.

3. Waiting too long to schedule AC repairs

When your AC system's performance decreases suddenly, this can signal the need for AC troubleshooting or repair. And while it may be tempting to overlook these issues when they seem less critical, it's usually best not to wait until the system breaks down completely before scheduling service. Continuing to run an improperly functioning AC system can be costly — or even dangerous. It's always smart to have a malfunctioning system checked right away.

4. Using the wrong filter for your system

Using a high-efficiency filter with an older AC system can cause problems in your system's performance. While high-efficiency filters are designed to filter out more allergens and smaller particle sizes, they may prevent older systems from moving air as forcefully as they were intended to, actually lowering their efficiency. Because various filter types and numerous filter efficiencies are available, matching the filter to the system is the best way to achieve optimal results. The most dependable method for determining the highest-efficiency filter your system can handle is to consult with a local HVAC or AC technician, who can inspect your system and provide an expert recommendation.

5. Failing to clean or change your AC air filter regularly

Changing or cleaning your system's air filter is one of the easiest ways to boost AC efficiency. And while you can depend on your local HVAC contractor for most other AC maintenance tasks, air filters need cleaning or changing more often than your HVAC technician will service your system. Filters should be cleaned monthly and changed at least once every three months, so this is a task that you as the homeowner will need to handle yourself.

A dirty air filter is one major culprit in AC energy-efficiency issues. The air conditioner maintenance information posted at the above link states the following about this AC sin: "Clogged, dirty filters block normal airflow and reduce a system's efficiency significantly. With normal airflow obstructed, air that bypasses the filter may carry dirt directly into the evaporator coil and impair the coil's heat-absorbing capacity." The agency also notes that a clean air filter can lower AC energy consumption by as much as 15 percent.

6. Closing off unused rooms in an effort to save energy

Many homeowners believe that closing the registers and doors to rooms not currently in use will save energy, but this is a myth. Closing off these areas of your home actually makes your central AC system work harder, lowering its efficiency and potentially creating humidity problems. This practice may restrict airflow through the system while increasing duct leakage — particularly from ducts located in unconditioned parts of the home, such as the attic.

For greater energy efficiency and monetary savings, try installing — and using — a programmable thermostat instead. A programmable thermostat will allow you to schedule your AC system's operation based on your family's lifestyle, schedule and AC usage patterns. You might also consider using a zoned system if the cooling or heating needs of different parts of your home vary markedly.

7. Not using ceiling fans — or not using them correctly

Ceiling fans can help save you money in winter and summer. By setting your fans to the correct mode for cooling or heating and using them only in occupied rooms, you can increase your AC or heating system's efficiency, experiencing net energy savings despite the electricity needed to run the fan. However, you should be aware that careless or improper use of ceiling fans can actually increase energy use. In addition to using ceiling fans, ENERGY STAR offers a list of several other handy tips for boosting AC or heating system efficiency.

8. Blocking return air vents

Placing furniture or other items in front of return air vents can prevent the system from functioning properly since the air returned to the central AC unit is the same air the system redistributes to your living space once it's been conditioned. Blocking the flow of air will ultimately decrease your comfort by reducing the efficiency of the system and could potentially cause the system to malfunction. Dust buildup on the vent covers can also compromise system efficiency while lowering indoor air quality.

9. Ignoring your home's overall energy efficiency level

The ENERGY STAR Home Energy Yardstick can help you assess the energy efficiency of your home. Before making any specific home energy-efficiency improvements, however, you might find the guidance offered by Home Performance with ENERGY STAR helpful. This program can make your home more energy efficient while helping you qualify for a federal energy tax credit.

10. Not recognizing when your AC system needs an upgrade

If AC repair bills have become a normal part of your budget, your system is likely nearing the end of its useful life. Even if repairs aren't too frequent, you may notice that your system isn't cooling or dehumidifying your home as well as it used to or that your energy bills are consistently rising. If your system is receiving proper maintenance, these issues should normally not occur. However, as an older system becomes less and less efficient, your comfort level decreases while your energy costs increase — a doubly unpleasant situation. When this combination of factors occurs, you may want to consider investing in a new, higher-efficiency air conditioner.

Let Comfort24-7 Help You Find Local AC Maintenance or Service

The Comfort24-7 network of HVAC professionals can help you avoid the above 10 "AC sins." Check our contractor listings for providers throughout greater Chicagoland, Northwest Indiana and Southwest Michigan.


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