1. SEER (Seasonal Energy Efficiency Rating). The SEER of an air conditioner is a measure of its cooling efficiency. The higher it is the more efficient the system. The minimum SEER allowed by the US government is 13. You can find AC systems with ratings as high as 18 and even 23 though they are expensive.
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2. Cooling capacity (tonnage). The cooling capacity of a central air conditioner is measured in units called tons, where one ton is equal to 12,000 British Thermal Units or BTUs. Most central AC systems range in capacity from 1.5 tons to 5 tons. The price increases with capacity. To figure out what size is ideal for your home, most contractors use a scientific calculation method referred to as Manual J Load Calculation.
Related Article: Read This Sizing Guide Before Buying Any HVAC Unit
3. Quiet-operation systems. When buying a new central AC, look for those that operate quietly. New central AC systems have advanced features specifically designed to keep operations as quiet as possible. The average sound range for central AC is from 54 dB to 85 dB. Remember that 70 dB is twice as loud as 60 dB. Long-term exposure to over 80 dB can potentially hurt your hearing. Buying a variable speed compressor central AC can keep the sound level under 60 dB.
4. Variable speed blower. Recent models of air conditioner come installed with a variable speed blower instead of the traditional type. This blower operates at a variety of speeds, which results in energy savings, less noise and minimizing of cold drafts getting into the house. If your air conditioner has the traditional blower, talk to a professional to see whether it is possible to install a variable speed one.
Related Article: 5 Benefits Of Variable Speed Fan