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Replacing a Central Air Conditioner: Efficiency and Furnace Match

ENERGY STAR central air conditioners use 8 percent less energy than conventional new models, and the higher price is paid back over time through lower bills. ENERGY STAR recommends replacing the heating system at the same time, especially if your furnace is over 15 years old.

What ENERGY STAR models save

ENERGY STAR certified central air conditioners have higher SEER and EER ratings and use 8 percent less energy than conventional new models. They can cost more up front, but the difference is paid back over time through lower energy bills. [1]

Why the furnace matters

A central air conditioner relies on a blower motor, which is usually part of the furnace. To make sure a new air conditioner performs at its rated efficiency, ENERGY STAR suggests replacing the heating system at the same time, especially if the furnace is more than 15 years old. [1]

After installation

Regular maintenance helps prevent problems and unwanted costs. ENERGY STAR also recommends sealing the home and its ducts so the new system performs well. [1]

What to ask an installer

  • How did you work out the size of unit my home needs?
  • Is the model ENERGY STAR certified, and what are its ratings?
  • Does my furnace or air handler need replacing too?
  • Will you check and seal my ducts?
  • What do the equipment and labor warranties cover?

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Questions

How much do ENERGY STAR air conditioners save?

They use 8 percent less energy than conventional new models, according to ENERGY STAR.

Should I replace my furnace when I replace my AC?

ENERGY STAR recommends it, especially if the furnace is over 15 years old, so the new air conditioner reaches its rated efficiency.

Sources

  1. Central Air Conditioners, ENERGY STAR

This guide is general information, not professional advice. It summarizes the sources above, which were last checked on October 22, 2026. Talk to a licensed contractor about your own situation.

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