How low can I set my AC thermostat?

Author: Emmett Wiza  |  Last update: Monday, June 29, 2026

For example, HVAC specialists recommend setting your thermostat no lower than 20 degrees the outside temperature. Suppose the outdoor temperature in your area is a blistering 90 degrees Fahrenheit. It's probably best to keep your thermostat between 70 and 80 degrees Fahrenheit to prevent stress on your unit.

How low is too low to set AC?

A common rule of thumb is that most models can function properly only above 68 degrees Fahrenheit. Any lower temperature will result in the system freezing up. In addition to a frosty refrigerant, the piping and coils could also become covered with ice.

What is the lowest you can set your thermostat?

What's The Lowest Temperature I Can Set My Thermostat in Winter? Do you just love the cold so much you'd rather not run any heat in winter? The winter thermostat setting should at minimum be between 50-55 degrees to keep your appliances and pipes from freezing.

Is it okay to set my AC to 68?

IS 68 TOO COLD FOR AC? Setting your AC to 68°F might feel too cold for some, especially in residential settings, as it is lower than the typical comfort range. However, preferences vary, and this temperature might be suitable for those who prefer cooler environments.

Is 72 a good temperature for air conditioning?

This is more of a personal question, as different people feel comfortable at different temperatures. Since 72 degrees is generally agreed upon to be an ideal indoor temperature, most people would probably still feel comfortable setting their AC units slightly higher than this, perhaps at around 75.

What is the ideal temperature for your home? The Answer Might Surprise You!

Is 75 too low for AC?

If it's just you and your spouse, you may be fine with the temperature set at 75-77. But if you have kids and pets running around, or you're cooking and using your oven, these things can all raise the indoor temperature noticeably. So, you might find a temperature setting in the 72-74 range more comfortable.

How cool should my house be if it's 100 outside?

For many of us, 70 degrees is the ideal indoor temperature, but when it is close to 100 degrees outside, your AC unit will be working quite hard to meet these expectations. Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits.

What is the lowest temperature I can run my AC at?

When it comes to maintaining a comfortable indoor climate while saving on energy costs, it's crucial to understand the minimum temperature for running your air conditioner. The lowest outside temperature at which to run your AC is typically around 60-65 degrees Fahrenheit.

Why not set the thermostat at 72?

Setting the thermostat below 72 degrees while using an air conditioner can cause the unit to work harder than necessary, leading to higher energy bills and potential damage to the appliance.

Does keeping the AC at 72 save money?

Best AC Temperature Settings While You Are Home

As you consider the most comfortable room temperature for your lifestyle and family, keep in mind that for each degree that you set your thermostat above 72 degrees, you can save up to 3% on your energy bill.

How low is it safe to set your thermostat?

Save money on your energy bill

Instead, you can lower your thermostat to be in the 50° to 60° range to save money. That said, we don't recommend setting your thermostat any lower than 50° because it could put your pipes at risk (more on that below).

Is 66 too low for AC?

The Perfect Temperature

70°F is an ideal temperature setting, regardless of how hot it gets outside. This is a comfortable temperature for most, though you may find that it can feel too cold at times. Any air conditioner set lower than this is at risk of having its coil freeze.

What's the lowest temperature you should keep your house at?

The World Health Organization (WHO) recommends setting your thermostat no lower than 64 degrees (F) in the Winter months while people are in the home. If there are infants or elderly individuals, they recommend keeping the temperature at 70 degrees at a minimum.

Is 67 too low for an air conditioner?

When the AC temperature is too low, between 60-67 degrees F (15-19 degrees C), the evaporator coil inside the unit can get excessively cold. If the humidity in the room is high, condensation can accumulate on the coil, which may lead to the formation of frost or ice.

What is the lowest I can put my AC?

In short, the 20-degree rule of air conditioning states that you should always keep your AC unit at no more than 20 degrees lower than the outside temperature. It means that, if the outdoor conditions are at 95 degrees, you should set your thermostat at no less than 75 degrees.

Is 69 too cold for AC in summer?

While it can be tempting to crank your thermostat down to the 60s after a long, hot day, keeping your AC at around 73-78 degrees is ideal for maintaining the efficiency of your system.

Is 72 a good temperature for air conditioning at night?

The National Sleep Foundation says 60-67 is a good temperature for sleep, but that might be too cold for you and increase your cooling bill. As a compromise, 70-plus degrees is a good setting.

Is it better to leave AC at a set temperature?

If You're Leaving Home for the Day or Weekend ...

"It's more energy efficient to keep the unit on but turn the temperature setting up," she advises. Turning off the AC unit during the day is not necessarily a bad thing — it is a myth that the AC unit has to work extra-hard to cool off a hot house.

Is it bad to turn the thermostat up and down?

There's a myth that adjusting your thermostat throughout the day uses more energy than keeping it at a steady temperature. But it's just that. A myth. By adjusting your thermostat somewhere around 7°-10°F for eight hours a day, you can actually save about 10% on your energy bills.

Is it bad to set AC too low?

Lowering the temperature too much causes your air conditioner to operate longer, causing more wear and tear on it as well as higher utility bills.

What temp is cheapest for AC?

You can also reduce your energy costs significantly by raising the temperature while you are at work, away from home, or asleep. For the greatest savings, consider setting your thermostat to: About 78 degrees while you are at home. About 82 degrees while you are sleeping.

Is 68 degrees too cold for AC?

An AC unit is happiest creating space temperatures no lower than 68 degrees fahrenheit.

How low can I set my AC on a 100 degree day?

For the most efficient performance, set the thermostat 20 degrees lower than the temperature outside. On a 100℉ day, set it to 78℉ to 80℉ to manage utility costs. If there's a lack of airflow, the filter may need to be changed or AC vents cleaned.

How cool should my house be if it's 110 outside in summer?

The California Energy Commission recommends that homeowners set their thermostat to 78 degrees when they're home and 85 degrees when they're away from home during the summer.

How long should it take to cool a house from 80 to 72?

Cooling a house from 80 to 72 degrees is a common goal for many, especially during the peak of summer. On average, this process takes roughly two and a half to three and a half hours.

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