The short answer to this question is “yes,” but don’t worry, we’re about to elaborate!
At some point or another, perhaps you’ve wondered just how cold a central air conditioner can actually get. You likely already know what the lowest setting is on the thermostat. For most models, it’s about 60–62°F, which is too cold for most people.
In the case of an extremely hot day, how much power can you actually get from your air conditioner? How cold can you get the air to ensure you’re as comfortable as possible when indoors?
We’re happy to answer these questions, regardless of whether if you’re reading this in the middle of a sweltering hot day and wondering if your air conditioner has something wrong with it, or even if you’re simply just curious. Helping you understand the limits of an air conditioner will also help you learn how to operate it more efficiently, give it a longer service life, and even potentially reduce the number of repairs it might need throughout that service life.
The 20° Limit
Your centralized air conditioner, whether it’s a traditional split-system, heat pump, or ductless air handler, has the ability to lower the temperature indoors by 20°F compared to the temperature outside. This is true for any type of air conditioner, and only if that air conditioner was properly matched for your home and sized correctly for the space it is intended to cool.
It most cases, particularly in our climate, this is more than enough to enjoy comfort. For instance, even if temperatures soar up to 90°F, you’ll still be able to cool the interior of your home down to 70°F, which is lower than most people find comfortable anyway. The insulation of your home plays a role in this too. Most people think about insulation keeping heat inside during the winter, but what it does is restricts heat transfer in or out, so it can keep the warm outdoor temperature outside where it belongs.
The U.S. Department of Energy recommends setting your air conditioner to 78°F during the day when household occupants are inside. This makes it easier for your air conditioner to manage hot days efficiently. The smaller the difference is between indoor and outdoor temperatures, the slower heat moves indoors, and the easier it is to maintain indoor comfort.
“What If I Go Beyond the 20°F Limit?”
If you push your air conditioner to cool your home lower than 20°F to what it is outdoors, your air conditioner’s compressor will keep running as it struggles to reach an impossible goal. This is a waste of energy and subsequently a waste of your money, plus it shortens equipment life since the air conditioner will accumulate wear and tear faster.
Lastly, the compressor can burn out. Fortunately, this isn’t a huge problem for homes in Sacramento, but it’s important to remember nevertheless. We all know how heatwaves can hit and we can face triple digits for days. We know it’s tempting to lower that thermostat as much as possible. But we really encourage you to pay attention to how efficiently you use your system.