There are a few factors you need to consider when looking for a new, energy-efficient central air conditioner for Raleigh's humid climate. First, there is the general efficiency to consider, which is measured by the Seasonal Energy Efficiency Ratio (SEER). The higher the SEER you can find the better, but an AC with a higher SEER will also be more expensive upfront. However, it will pay itself in the long run through savings on your utility bills.

If you want to qualify for most AC rebates and the federal Residential Energy Efficiency Tax Credit, which covers up to 30 percent of the cost of new central air conditioners for up to $1,500, you’ll need to purchase a central AC (split system) with a SEER of 16 or higher.

Besides SEER, you should also consider the Sensible Heat Factor (SHF), which is important in humid climates like Raleigh’s. A system with an SHF between 0.67 and 0.74 will do a good job of removing humidity from the air, which is important for the respiratory health of the people living in your home. However, you should keep in mind that systems with lower SHFs tend to be less efficient.

Finally, you should consider upgrading your ductwork with air sealing and insulation. This will increase the overall efficiency of your system, which will allow your air conditioner to not have to work as hard. You can also add insulation and air sealing to your home in order to help it retain the cold air your AC system is producing. An energy auditor in the Raleigh area will be able to help you make these upgrades as well as help you find a system that is sized properly for your home.

Updated July 27, 2010