Central Air Conditioning

Central Air Conditioning

Central Air Conditioning systems are used to cool large portions of homes.  They are large energy users and account for much of the summertime home energy usage in the United States.

Quick Links:
How to buy?
What are my Options?
Energy Saving Tips
What do I ask a contractor?
How much can I save?

How To Buy?

Rules of thumb for equipment sizing do not work in modern homes and should not be used. Unfortunately, rules of thumb are still prevalent.
For the best results in comfort, efficiency, and durability, integrate HVAC system design for both equipment and ducts in the overall architectural design. Work closely with a HERS rater, HVAC engineer, or HVAC contractor to properly design, size, and select HVAC equipment. If done properly, this single step goes a long way toward improved energy efficiency and comfort and substantial cost savings.

The Air Conditioning Contractors of America (ACCA) has published simple but effective methods for determining loads and sizing ductwork and heating and cooling equipment.

• Manual J tells how to calculate loads.
• Manual D tells how to size ducts.
• Manual S is a selection guide of appropriate heating and cooling equipment to meet identified loads.

For more information or to purchase these documents on the Web, go to the ACCA Web site.

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What Are My Options?

The Consortium for Energy Efficiency (CEE) and the Air-Conditioning and Refrigeration Institute (ARI) have developed an online database which can be used to find qualifying ENERGY STAR equipment. All equipment listed in this online database meets the specification requirements for ENERGY STAR. This online database is solely maintained and operated by CEE and ARI.

Search CEE-ARI Online Database

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Energy Saving Tips

Central air conditioners should be rated at a minimum of 13 SEER for air cooling and heat pumps should be rated at a minimum of 7.6 Heating Season Performance Factor (HSPF) for heating. In September 2006 DOE began enforcing a 13 SEER standard for all residential central air conditioners.

Until recently, SEER-10 air conditioning equipment has been standard across the country. But SEER-11 and SEER-12 equipment is becoming more widely used. SEER-12 equipment is nearly always cost-effective. Consider using SEER-14 air conditioning equipment to achieve performance levels greater than 30 percent savings. Equipment with SEER ratings up to 20 are now available. Currently, ENERGY STAR-labeled central air conditioners have a minimum rating of SEER 12.

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What Do I Ask a Contractor?

You can get better performance out of your cooling equipment by sealing your home and making sure your ducts don't leak.

Also, make sure that your contractor is not over-sizing the system, as discussed above.

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How Much Can I Save?

If your central air conditioning unit is more than 12 years old, replacing it with an ENERGY STAR qualified model could cut your cooling costs by 30 percent.

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