Choosing an Air Conditioning Unit for Your Home


by Marcus Pickett

Given the average life expectancy of an air conditioning unit is about 15 to 20 years, most people will need to install a new system at least once or twice during their lifetimes. Your turn may be coming soon. As you prepare to choose and install a new unit, here's what you need to know and pay attention to so you can make the best choice possible for your home.

What You Need to Know about Air Conditioning Units

  • Want to know how energy-efficient various models are? Look at the Seasonal Energy Efficiency Ratio (SEER) ratings. This rating essentially measures the amount of cooling output versus the amount of electrical energy put into the system. Today, the minimum SEER rating is 13, as mandated by federal law. For an Energy-Star label, the unit must have a minimum SEER rating of 14. Older units may have a rating of 9 or lower. Some modern units have a rating as high as 20.
  • The most common mistake homeowners (and contractors) make is over-sizing their A/C unit. Although you do need a unit large enough to survive the hottest days of the year, ideally your unit should be running continuously. A/C units are inefficient when they first start up. Plus, an actively running air conditioner dehumidifies the air in your home, allowing warmer temperatures to feel cooler.
  • The role between air cooling and humidity is especially important in dry climates, where low humidity levels allow for energy-efficient evaporative cooling. This process pulls heat out of the air to evaporate water in the same way that your body cools itself, as sweat evaporates off your skin.

Cost and Time Associated with A/C Installation and Repair

It's tough to estimate the cost and time associated with air conditioning installation. The contributing factors that weigh in on a swamp cooler for a 1,500 sq. ft. home in Phoenix, AZ and a conventional air conditioning system for a 2,500 sq ft. home in Chicago, IL are so different they might as well be separate projects. That said, ServiceMagic, the leading online resource connecting homeowners and home improvement contractors, has compiled the following averages from projects actually completed by homeowners from across the country. Keep in mind when looking at these averages that individual projects can cost less than $2,000 or more than $20,000:

Free, Supplemental Air Conditioning

No matter what else you do, no matter how energy-efficient your A/C unit, no matter how highly rated your insulation, a few, simple actions will reduce your system's energy consumption, helping the environment and saving you money each month. Pull your window coverings closed in the morning and open them back up in the evening. Install an automated thermostat that will allow you to leave the temperature higher when you're not home. Install ceiling fans in higher traffic areas of your home. Not only will these steps reduce energy consumption, but they may allow you to install a smaller unit in the first place, literally saving you thousands of dollars in the upfront cost of installation.

Research, Planning Lead to the Best Choices

You need to research the possibilities for a new air conditioning system and plan accordingly. To do this, you need to have some idea of when your old A/C unit may go kaput. If your current system is getting up there in years - remember the average life expectancy is 15 to 20 years - you should have an HVAC contractor inspect your system each spring. Ask whether your system has what it takes to make it another year and how much longer the contractor thinks you can expect from the system in general. Trying to save and/or finance the cost of a new unit in the period of just a couple of months is hard enough. Trying to make a wise choice after your unit has failed and it is 90 degrees inside your home is virtually impossible.

Read more about Shopping for Air Conditioners.

-- Marcus Pickett is a senior home improvement writer with He has written more than 1200 articles on managing your home and home improvement trends.