Central air conditioning systems can last from 15 to 20 years. Sticking with an older unit may be less expensive in the short run, but not when it comes to helping you save money off monthly utility bills. Here’s some information to help you make a better decision when it comes time to get a new, energy-efficient central air conditioner.
A Few Facts on Air Conditioning and Energy-Efficiency
If you’re wondering whether it’s time to replace or upgrade your central air conditioning system, here are a few facts that might help:
- In the average air-conditioned U.S. home, air conditioners use more than 2000 kilowatt-hours of electricity per year.
- Producing the electricity needed to air condition the average U.S. home causes the average power plant to emit about 3500 pounds of carbon dioxide and 31 pounds of sulfur dioxide per year.
- The most energy-efficient air conditioners on the market today consume 30 percent to 50 percent less energy than models manufactured in the mid 1970s.
- Even if your air conditioner is just 10 years old, upgrading to a new energy-efficient air conditioner could save you from 20 percent to 40 percent off your cooling costs.
The Two Types of Central Air Conditioners
If you decide to replace or upgrade your central air conditioning system, the first thing you’ll need to know is whether you have a split-system central air conditioner or a packaged central air conditioner.
Split-system central air conditioners are made up of an outdoor metal cabinet containing the condenser and compressor and an indoor cabinet containing the evaporator, which in many split-system air conditioners, also contains a furnace or the indoor part of a heat pump.
Packaged central air conditioners contain the evaporator, condenser and compressor in a single outdoor metal cabinet, usually placed on a concrete slab next to a home’s foundation. From the cabinet, air supply and return ducts enter a home through its exterior wall and connect to a series of internal supply and return ducts in order to circulate cool air throughout a home. Packaged air conditioners usually include a natural gas furnace or electric heating coils and eliminate the need for a separate indoor furnace.
If your home already has a furnace but no air conditioner, then installing a split-system air conditioner is the most economical choice.
How to Judge the Energy Efficiency of a New Central Air Conditioner
When shopping for an energy-efficient central air conditioner, you’ll need to research a system’s seasonal energy efficiency ratio, or SEER, which indicates how much energy a model uses to produce a specific cooling output. If you have an older system, chances are it has a SEER rating of 6 or less.
Since Jan. 23, 2006, models have been required by the Environmental Protection Agency to have a minimum SEER rating of 13, which require 30 percent less energy to run than models manufactured with the previous minimum SEER rating of 10.
The most energy-efficient central air conditioners on the market today are ENERGY STAR–certified with SEER ratings greater than 13.
Tips for Buying a New Central Air Conditioner
Buying a new central air conditioning system doesn’t have to be intimidating. Here are a few tips on what you should look for in a new system:
- Size matters when it comes to a new central air conditioner. If your unit is too small, it will have to work too hard to cool your home, which can result in higher electric bills and damage to components. It may not even be able to reach comfortable temperatures on hot days. If your unit is too big, it will cycle on and off too quickly, which will prevent the unit from removing humidity from the air and can also damage components. Only a right-sized unit will provide the performance, operating life and energy efficiency you expect. Know your home’s square footage and consult with an HVAC contractor before you make a purchase.
- Partial replacement may not be ideal. Although you can replace the outdoor compressor on an older model with a modern, high-efficiency unit, you should consult a local HVAC contractor to make sure that the compressor is properly matched to the rest of the older system. Even if it is, changes in refrigerants and air conditioning designs over the years usually mean it’s a wiser decision to replace the entire system.
- Look for an air conditioner with an EER rating of 11.6 or greater. An air conditioner’s EER rating is different from its SEER Rating. EER is an air conditioner’s thermal expansion valve and a high-temperature rating and determines how efficiently the unit runs when the weather is at its hottest.
- Make sure the system runs quietly.
- Look for systems that have a variable speed air handler for new ventilation systems, an automatic-delay fan switch that turns off the fan a few minutes after the compressor turns off and a fan-only switch so you can take advantage of nighttime ventilation that can significantly reduce cooling costs.
- Find a system that has a check filter light to remind you to inspect the filter after a certain number of operating hours.