SAN DIEGO, CALIFORNIA — Are you starting to research replacing the heating and cooling system in your San Diego home or business? Put a two-stage unit on the list of options to consider.

Two-stage cooling means the air conditioning unit or heat pump has a compressor with two levels of operation: a high setting for hot summer days and a lower setting for milder days.

“The two-stage system is kind of like having two systems because of its two levels of output,” says Gabriel Carini, who has more than 15 years of experience in the air conditioning and heating industry. “On its low stage it runs at 60 percent of output, and on its high stage at a hundred percent.”

Considering the relatively mild climate of the San Diego area, two-stage systems are great for homeowners and business owners because the maximum output is rarely needed. The system runs at the more efficient setting most of the time, but still has the blast of cold air needed for those very hot days.

According to Carini, most homeowners will be using the low-speed operation the vast majority of the time. When the unit is running in the low setting, the system runs longer, providing more consistent temperatures and more effective humidity control, which both aid in your comfort. When compared to a single-stage unit, a two-stage air conditioner is capable of removing twice as much moisture from the air.

“Two-stage air conditioning systems are also more efficient,” says Carini, who specializes in residential and business heating and air conditioning services. “You will see a big difference in your utility bill.”

Efficiency is judged by the unit’s Seasonal Energy Efficiency Rating or SEER. All air conditioning and heating equipment in the U.S. is required to have the efficiency rating that reflects the percentage of energy used efficiently. More efficient systems have higher ratings.

“New air conditioning equipment has to be a minimum SEER of 13, but we often install air conditioning systems with SEERs in the high teens,” says Carini, who offers air conditioning repair, service and installation. “The higher the SEER rating, the greater your energy savings are going to be.”

The Energy Departments says that many older systems have SEER ratings of six or less, so installing any new heating and cooling system will mean an automatic decrease in energy consumption and utility bills. However, running in the lower setting of a two-stage system means the air conditioner is using significantly less energy the majority of the time.

“If you’re looking for optimal comfort and a quieter, more efficient system, a two-stage cooling system might be a good option for you,” says Carini. “You can count on your system to keep you cool and comfortable no matter what the weather conditions are outside.”