Practical Advice for Installing an Air Conditioner

Updated: May 23, 2023

If you're considering a central air conditioner install for your new or existing home, consider these tips before making any decisions.

In the Midwestern, Western and Southern U.S., central air conditioning is by far the the most popular AC system in homes. Central air conditioners (AKA whole-house air conditioners) offer a quiet, energy-efficient way to keep a home cool. However, unlike window air conditioners, they are not the most DIY-friendly to install.

Choose the Right Type

There are two main types of central air conditioning units. The most common is a split system, where the condensing unit is outdoors while the evaporator coil and air handler are indoors. In the second type, known as a package system, all three components are installed in the same place. The box is usually placed on the roof or the ground close by. The ducts connect directly to it.

Split systems are more affordable, quiet and efficient than package systems, which are typically only used in commercial buildings.

A woman is pressing the up button of a wall attached house thermostat with digital display showing the temperatureGrandbrothers/Getty Images

Consider Energy Efficiency

Jay Kline, general manager at Penguin Air, Plumbing & Electrical, recommends checking a system’s seasonal energy efficiency ratio (SEER) before buying. The SEER rating indicates the total cooling capacity over the amount of energy used in the same period of time.

The minimum SEER you’ll see on a new central air conditioning system today is 13, but SEER ratings go up to 24. Older systems will typically have a SEER of 10 or less, so even lower-rated new systems are a step up in efficiency.

Choose the Right Size

With residential central air conditioning systems, bigger is not always better. Kline warns that air conditioners too large for the home can hinder proper cooling. To determine the correct size, contractors use a heating, ventilation and air conditioning (HVAC) load calculation. It starts with the home’s square footage and considers other factors, such as the climate, insulation grade, number of windows and doors, and number of occupants.

The same variables also factor into the British Thermal Units (Btu) needed to cool the home. It’s often best to consult with an HVAC professional when sizing a home air conditioner system.

man looking at air conditioning bill Jose Luis Pelaez Inc/Getty Images

Set Clear Expectations to Lower Costs

The cost of a central air conditioning system varies on the size and design of the home. There are a lot of customizable options for efficiency, air filtration, zoning, smart system, ducting and insulation.

According to Tyler Zegarzewski, an HVAC Service Manager for AirCo, partial system replacements can cost as little as $2,000. The most efficient systems, with complete duct replacement, zoning, indoor air quality upgrades and filtration for a large home, can cost as much as $40,000.

Zegarzewski says, “If you are looking to get a lower price, be straightforward about what you are expecting and provide a date you intend to have the work completed.” The more you show that you’re a serious buyer, the more willing a contractor will be to work with you to find the best solution for your needs.

Inspect the Existing Ductwork

Before installing a central air conditioner, have your existing ductwork inspected. Not all ducts can handle the higher level of airflow from a new air conditioning system, and modifications might be needed. In homes without existing ductwork, it will need to be installed. Modifying or installing new ductwork can add thousands to the cost.

For homes without ductwork, split-ductless systems are often a better choice.

Place It in the Right Place

When installing your air conditioning unit, consider exposure to direct sunlight and water, as well as obstructions in the area. Kline recommends placing the condenser on the north side of a home because it gets the least direct sunlight, so it stays cooler.

Hiding your air conditioner behind bushes or large plants is not a good idea. It prevents proper airflow, plus loose branches and leaves can build up and cause damage. “A central air conditioner should have two to three feet of clearance on each side, as obstructions can prevent the system from adequately cooling,” Kline says.

When mowing, make sure you don’t accidentally blow grass clippings at the condenser. This will stress the motor and require it to work harder.

Technician repairing air conditionerbymuratdeniz/Getty Images

Do the Proper Maintenance

Regular maintenance can ensure your air conditioning system operates at its peak. Manufacturers also require annual maintenance to maintain warranties. Zegarzewski suggests checking your cooling system in the spring and your heating system in the fall. Preventative maintenance will improve efficiency, saving you money. Regular maintenance is also the best way to prevent pricey repairs.

While you can do your own HVAC inspections and maintenance, you might miss crucial details that a professional AC technician can spot. Plus, there are things an HVAC technician is licensed to do that you can’t, like adding refrigerant. However, you can check the air conditioner’s components, clear out dust and debris and change filters yourself.

Hire High-Quality, Reputable Professionals

Installing a central air conditioner is not usually a DIY-friendly job. While it’s certainly possible, the most homeowners lack the necessary qualifications. With that in mind, it’s a better idea to hire reputable professionals. Ask for references, certifications and insurance from the company before you hire them.