I need to replace my A/C unit. What minimum SEER level should the new unit have?

Question

I need to replace my A/C unit. What minimum SEER level should the new unit have?

Asked by abraham

I am looking for an efficient make and model, and to be able to compare different brands I would like to know what SEER level is recommended.

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Answers

Tammy Schwolsky, LEED AP, GPR, HPwES's picture

The most important factor when purchasing any HVAC equipment is to make sure that it is sized correctly.

When a home is well-insulated and properly air-sealed, a smaller system is usually recommended. When your home is leaky and your ducts are leaky, you do need a larger system to keep your home comfortable. But a larger system costs more money upfront and to operate. Why buy a high-efficiency system if it is being wasted through gaps and duct leakage?

Here are my recommendations:

  1. Have a blower-door and duct-blaster test performed (energy audit).
  2. If needed, upgrade the envelope of the house and the ducts, then test for combustion safety.
  3. Purchase an A/C that is the right size for your well-sealed home. Larger systems can short-cycle, which affects efficiency, comfort and durability.
  4. A 14 SEER Energy Star rating is the minimum and if designed and installed correctly will be just fine. Make sure that your HVAC contractor understands efficiency and that a duct-blaster test is performed post-installation. If the ducts are brand new a minimum of 3% duct leakage is acceptable.

If the envelope and ducts are tight and the system is designed for a balanced air flow, a 2,000 sq. ft. home can be comfortable with a 2-ton system.

The FREUS is a watercooled condensing unit with a good EER rating -- check it out.

If you get a chance, let me know how it goes.