Photo by The Electric Cooperatives of South Carolina
Q: My home’s central air conditioner is at least 15 years old—not very efficient, but it still works. Should I replace it now or wait until it fails?
A: Replacing an inefficient air conditioner with a more efficient model could significantly reduce your electric bill. A new AC unit is 20 to 40 percent more efficient than one from the 1990s, and Energy Star-certified systems are even more efficient. Replacing an aging system now, before summer starts, could help you avoid installation delays or price premiums.
How much money you may save depends on how often your AC runs and your electric rate. If you are in a hot climate and you keep your home’s temperature in the low 70s, your cooling cost will be substantial, and so will the potential savings from replacing your old air conditioner with an efficient new one.
The best way to determine possible savings is to have an in-home assessment conducted by a qualified heating, ventilating and air conditioning professional or a certified energy auditor (see resnet.us to find energy-efficiency professionals). Contractors should be knowledgeable about energy-efficient systems and have good references. It’s a plus if they have North American Technician Excellence certification. Electric co-ops are often interested in reducing peak summer loads and may be able to offer helpful information.
Your contractor needs to size the system to your home. A unit that is too small will not cool your home to the levels you want. If it is too large, it may not dehumidify your home sufficiently, and it will cycle on and off more frequently, which can increase wear and tear on the system and shorten its life significantly.
To size the system, the contractor will assess your insulation levels. By adding insulation where it’s most needed, you may be able to install a smaller AC unit and enjoy greater comfort and lower cooling costs. Your contractor should also assess your ductwork, which may be poorly designed, leaky or inadequately insulated.
Air-conditioning options are suited to different situations. Ask your contractor whether it’s practical to change to a different type of system.
- Central air conditioning is generally either split or packaged. A split system, which has the cold coils inside the home and an outside unit exhausting heat, is the most common. Packaged systems, which are sometimes installed
- because of space constraints, combine these functions into one box located outside the home.
- A heat pump can provide cooling and heating in homes with or without ducts. If you are currently using propane or natural gas as your fuel source, this may be a good option.
- A ductless mini-split heat pump can be an efficient way to cool up to four zones inside the home. If your existing ductwork is in bad shape or poorly designed, this could be a good solution.
- Window units are much less efficient than other options, but they can be effective for cooling a single room. It’s worth paying a little more for a new Energy Star-compliant unit.
Replacing an aging air conditioner is a great way to improve comfort, cut energy costs and reduce peak energy demand. You can learn more about home cooling at energy.gov and find information about energy-efficient products at energystar.gov.
Send questions to Energy Q&A, South Carolina Living, 808 Knox Abbott Drive, Cayce, SC 29033, email email@example.com or fax (803) 739‑3041.