Using the Air Conditioner in Winter: Is It a Good Idea?

For a homeowner, your air conditioning in San Diego is a trusted companion during the sweltering summer days of Southern California. They regulate the temperature during hot weather, enabling us to relax in more comfortable temperatures. But can an air conditioner be used to heat up your home in cold weather, too? Have you, like many others, heard that using your AC in winter is a bad idea? Leading HVAC contractors in San Diego, Murrieta, Temecula & San Marcos give answers to common questions about using air conditioners for heating.

An AC installation done by Action AC

Can you use an air conditioner in the winter?

If your air conditioner has a functioning heating element, it is considered a reversible air conditioner, so you can also use it to heat your home. Reversible air conditioners are specifically designed to be used when outside temperatures are higher than indoors. Thus, it won’t be as high-efficient at producing heat compared to its cool air production in the summer. Homeowners in San Diego and more inland cities choose to use a reversible AC for extra heat in addition to a furnace. If you’re interested in reversible air conditioner installation in San Diego or the surrounding areas, connect with our team!

It is important to keep in mind, however, most air conditioners are simply not designed for cold weather use. Some even have factory-installed low-ambient controls, which help prevent functioning in low temperatures. Essentially, certain air conditioners can be used in the winter, but you’ll most likely be running your system outside its designed parameters.

If you choose to run your air conditioner when the temperatures are too low, you may risk causing significant harm to your unit, necessitating AC repair in San Diego from Action AC. Air conditioners contain oil designed for lubricating the compressor, and this oil works best in warm weather. In winter, the oil can become thicker due to low temperatures, preventing proper lubrication of the compressor and potentially causing it to overheat. Another issue with running air conditioners in the winter is the condensation which collects on the cooling coils might freeze and damage the system.

What is the coldest temperature for an air conditioner?

While using your air conditioner in winter does run some risks, you can still use it for heating unless the temperature outside gets too low. But what is too low? Most HVAC manufacturers recommend users don’t run their air conditioners for long periods of time if the temperature drops below 60 degrees. If you use it in lower temperatures, you risk compressor failure and frozen coils. If you want to test your unit and make sure there’s no built-up frost on the AC components, make sure to wait until the temps go above 60 degrees for at least three consecutive days to allow the oil to warm up. Addtionally, consider connecting with your local AC experts to schedule regular AC tune ups in San Diego or the surrounding areas.

What should my AC be set at in winter?

When using your air conditioner for heating, adjust the thermostat settings appropriately to save on energy costs. To do so, it is recommended to keep your thermostat within the 68-75 degree range for the best results. According to, you can get a 5-15% reduction of your energy usage per year if you lower your thermostat by 10-15 degrees, for about 8 hours a day.

Keeping your thermostat at 68°F during the day is quite a comfortable temperature, especially if you wear appropriate clothing. This particularly true if you live in San Diego or Temecula, where winter temperatures are usually milder.

Keeping your home comfortable during winter is even easier when you own a programmable thermostat. By allowing you to set your desired temperatures based on your habits, a programmable thermostat brings convenience and keeps you from being tempted to set a higher temperature.

Depend on your favorite San Diego HVAC contractors

Action Air Conditioning & Heating offers reliable, high-quality ventilation, heating, and air conditioning services to San Diego County & Temecula Valley. Our expert team is dedicated to meeting your cooling and heating needs throughout the weather changes. Do not hesitate to reach out if you’re considering an air conditioner replacement during winter, and wish to learn about furnace maintenance plans with benefits for you.

Whether you need us for air conditioner installation or just a routine furnace tune-up, rest assured our NATE-certified technicians will perform the job according to the latest industry standards. Call us today and let us bring you indoor air quality and peace of mind all year.


“Complete HVAC system install was done – very professional and clean workmanship. The techs were very communicative during the whole process. I am very pleased with the results . Thanks Action and your team for doing it right the 1st time.”

-John M., Google Review


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