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What is a Two-Stage AC System?

A two-stage AC system, also known as a dual-stage system, has a compressor that works at two different speeds. The compressor pumps the refrigerant through your air conditioner and controls the rate at which it cools your home. If your system has two stages, it can either run at full capacity on the high setting or at 60 to 70 percent capacity on the low setting.

This is an improvement over single-stage air conditioners which operate at just one speed. These systems are either on or off. When they’re on, they run at full capacity, whether you need all that energy or not. A two-stage AC system is better than a single-stage air conditioner because it can utilize the lower setting which uses less energy. The lower setting also puts less strain on your system as a whole, which means fewer repairs and a longer lifespan.

What is a Variable Speed AC System?

A variable speed AC system is even more efficient than the two-stage option. This type of system can operate at any capacity, making minute adjustments to the speed which will maximize your energy efficiency and deliver exactly what you’re looking for in terms of comfort. Variable speed systems typically run at lower speeds most of the time, providing steady, even cooling while using minimal electricity.

Variable-speed air conditioners are more effective at everything they do. They offer outstanding dehumidification, extremely precise temperatures, and even comfort throughout your living space. These systems also require even fewer repairs than their two-stage counterparts and have the longest lifespan when compared to other types of compressors.

Which Option is Better?

For temperature management, energy efficiency, and dehumidification, the variable-speed AC system is your best option every time. This is the latest in cooling technology. The innovation of variable-speed compressors changed the landscape for temperature management. You can cool your home to within half a degree of your programmed setting with this system.

There are, however, some cases where you might need to choose a two-stage AC system. If you can’t afford the higher price tag for a variable-speed air conditioner, a two-stage system is better than a single-stage installation. There is a significant price difference between all three options. If you can’t get to the highest performance tier with a variable speed AC installation, a two-stage system is a good compromise.

When Should I Upgrade to a New Installation?

You should start considering an upgrade to a new air conditioner if you’re noticing any of the following:

  • An unexplained increase in utility bills

  • More frequent AC repair needs

  • Your system doesn’t cool the home evenly

  • Your air conditioner is over 10 years old

These are all signs that your air conditioner is nearing the end of its lifespan. You might also choose to upgrade your AC system sooner if you’re simply looking for a more efficient option for your home. If your air conditioner has never quite delivered the cooling you’re after, it may be undersized for your home. Upgrading will help you get even cooling throughout your living space. If your utility bills are higher than you’d like, upgrading from a single-stage AC unit to a two-stage or variable speed system will have a notable impact on your electricity use.

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What others say


Angel and Robert were professional and installed a great system of the highest quality. It runs cold and quiet; what more could one ask for?? Great company; great staff; highest of quality and the highest of recommendation.

Joe Baratta

In the 5 years that I have lived in my SF valley home, I have had my AC and furnace die on me. Mike and his team gave me a great deal on new HVAC system, and 2 years later the furnace. I work in the construction industry, and confirmed quality installation and equipment. They paid attention to the little things too, which carries over in my experience. SoCal did maintenance, and the technician Dave recommended improving the duct intakes and filter system. Cannot wait for my home to be colder than a polar bear’s toenails this summer.

David Sire

Overall, this was a very good experience. Customer service was great! The price was reasonable. Installation was scheduled 2 days after we purchased the HVAC system,. They installed the system in approximately 5 hours, and there was no mess. This a very professional operation

Joseph Pecot

Your Expert you send out was so honest with me he was so nice and professional he told me what to do that I didn’t need what I thought I did I’m so use to people coming out and try to take me to the cleaners specially I’m a Senior a Woman and living alone if I ever need any service done I will call you in a Heartbeat you r Technician Danny was super nice and very Professional I’m so glad I found this Company

Ondina Santa Maria

Great people. A year ago they replaced my duct work so called them when I needed a new furnace. Prompt, quick turn around and very professional. I totally recommend this company!! On the same day, they installed a tankless water heater. These peeps are amazing!

LuAnn Hughes

Just the best service, honest, reliable company!! Have a new unit, love it.. and have told many people to use this company. I had 3 bids when I was looking for unit and sooo happy I went with my gut feeling! The best, they come out and service too, extremely happy.

Jodi Lasky

I have been unbelievably impressed and overwhelmingly happy with the quality of the service provided by the team at So Cal Climate Control. From the initial estimate to the install and everything else, everyone we’ve had on this project has been so friendly, professional, and detail oriented. Highly recommend this company if you are looking for HVAC work.

Julie Matos

Mike sent his team out when our AC failed on the hottest day. It was a late Saturday afternoon and we were staring down having to wait until Monday at the earliest to get someone out. Mike immediately told me his team would be there within 90 minutes, and they showed up on a Saturday evening within the hour! Great service!

Mary Goldstein

So Cal Climate Control was Home Adviser’s first choice, so I called and talked to dispatch. I had a technician ( Chris) at my door within 2 hours.
He was professional, courteous and their price was reasonable.

James Fisher

Wonderful company! From the moment they came to give us a bid for their services to the last minute they were here. Very professional, knowledgeable, and genuine. You will not spend any money you don’t need to spend, they are honest about the work your home needs done, but also honor whatever services you’d like to have done. They respond quickly, and promptly. We had our vents/registers cleaned, old ducts removed, & new ones installed, they took care of the whole process leaving nothing behind. Charles and his crew were great! Respectful, professional, and always on time. Would highly recommend.

Maria Hoz

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