What is the Best Temperature to Set Your Air Conditioner On?

What is the right temperature for AC? 70 seems a little cool. Some suggest 80F. What would Goldilocks say is “just right?” This post addresses the best temperature to set your air conditioner on – that is, the best thermostat setting for air conditioning.

Ah, summertime! Longer days, fun at the beach, family vacations, backyard grilling and a warm, stuffy house. Wait a minute! That’s why we have air conditioning, right?

According to the most recent Residential Energy Consumption Survey (RECS), 87 percent of U.S. households are now equipped with AC. This includes all housing types and in every region. It seems like most people have found it important to make their living space cooler and drier during the hot summer weather. An air conditioned home means a more comfortable temperature and lower humidity indoors.

What is the Best Temperature to Set Your Air Conditioner On?

One of the issues that presents itself to those who have air conditioning is what is the best temperature to set the system on? For some, the answer to this might simply be, “whatever feels right.” The U.S. Department of Energy suggests 78F as the ideal temperature setting for your AC. That may or may not be ideal for you and your family; you may find that a temperature little lower – or even higher – suits you better. But as you decide on the temperature issue, consider another factor – the cost of keeping cool.

Energy Cost and How to Control It

Here’s the unfortunate truth: AC costs money. All air conditioning systems use electric energy to provide the cooling effect in our homes during warm weather. The U.S. Energy Information Administration recently reported that the average electric bill for U.S. households is $111.67 per month, or about $1,340 per year. Since an air conditioner is primarily an electric appliance, how much of that is due to air conditioning? Between 17% and 27% on average, we are told, but in warmer climates it may be up to a whopping 70% of a summer electric bill!

Raising the temperature setting for an empty house is one way to help control that electric bill. Studies show that increasing the temperature setting 7 to 10 degrees anytime no one is home for at least two hours can lower electric use by 10%. You’ll need a programable thermostat or a smart thermostat to do this most easily. WiFi thermostats are another good option, and their cost is pretty reasonable.

Here’s how this works. The transfer of heat always occurs from warm to cool, since “cold” is simply the absence of heat. This means that in warm weather the transfer of the warmer outside heat into your house will actually slow down as the interior temperature increases. The result is that your house won’t warm up as quickly as you might think it would by raising the AC setting several degrees. Add to that the fact that your air conditioning system isn’t running as much while you are away, and it adds up to savings.

Thermostat Suggestions for AC

Using a programmable thermostat will almost always result in energy savings while keeping your home cool and comfortable when you need it. When the programs are set according to your schedule, your thermostat will do the thinking for you to raise the temperature when you are away, and lower it again when you will be home. 

You might also schedule it to allow the temperature to rise a few degrees at night, since our body temperatures drop slightly when we are sleeping and the best ac temperature for sleeping  is often a little higher. Of course, in winter, you can reverse this – cooler when you’re away (less heat) or under an extra blanket at night, and warmer when you are up and at home.

Geofencing – There’s a Cool Idea – Or a Warm One! 

You can read more about geofencing here, but the basic idea is that a phone app communicates with a smart thermostat to change thermostat settings when you are inside or outside of a geographical range that you determine. 

Set it and forget it (you’ve heard that somewhere else, but it works for programmable thermostats.) When you drive away from home and leave the geographic territory, your thermostat adjusts the temp to warmer in summer/AC mode and cooler in winter/heat mode. Drive back into the “zone,” and your thermostat will adjust to your preferred settings for when you're home. In summer, you’ll arrive at a nicely cooled home; in winter, it will be toasty warm. And in both seasons, your energy costs will be at least 10% lower.

Windows = Fresh Air = Higher Cooling Bills

Closing all windows is one key to saving on energy when the air conditioning is running. It may be tempting to leave one or two windows open “just a little” to have some fresh air coming in. But remember, during the day, that fresh air is warmer than your living space, so it will actually be fighting against your AC system, making it work harder and costing more money.

West and South Windows

Using sun-blocking window treatments will also help conserve energy by preventing the transfer of solar heat into your home. This can be accomplished with curtains, drapes, blinds or shades. We all know how much warmer it is in a vehicle on the side the sun is shining on; the same is true in your house. Your AC system will run less and cost you less when the sun isn’t pouring in through windows.

Insulation Has a Huge Return on Investment

Upgrading your home insulation is a sure way to lower your energy consumption. It will pay for itself quite quickly in most cases because it reduces energy use throughout the year. There are numerous ways to improve the insulation of your home, including adding insulation in the attic (#1 for ROI) and crawl space. If you have been thinking of re-siding your house or upgrading your windows, be sure to use energy-saving materials and add insulation where possible. Proper attic ventilation is another key to preventing the accumulated heat in your attic from getting into the living space and causing your AC to work harder.

Summer Kitchen

In the “old days,” many homes had summer kitchens detached from the main house to keep the heat of cooking (no microwaves) out of the living areas. It’s worth considering today. Cooking outdoors instead of heating up the kitchen is a great way to keep your AC from working overtime and costing more. Plus, you get that great taste of grilled food that you sometimes pay more for at a restaurant!

Air Filters – Keep them Clean

 Maintaining the air handler filters will also improve the circulation of cool air in your house and enable your AC system to operate at peak efficiency. Filters should be checked every 2-3 months and changed if needed. Having your entire cooling system inspected at least every two years will also ensure that there are no issues that would increase your energy bill.

78F – Feeling Cool and How to Improve It

OK – saving some money on electric usage is good, but you have air conditioning because you want to feel cool and dry rather than hot and sticky during the summer months. There are several things you can do to reach this goal while keeping in mind the recommended temperature of 78F inside your home.

Ceiling Fans: Install and use ceiling fans if you don’t already have them. Ceiling fans will not cool the air, but they will move the air so that you will feel cooler. This is because the natural moisture of your skin will be evaporated, and the evaporation process results in cooler temperatures – in this case – on your skin. Make sure the fans are turning in the direction that will move cool air downward in summer and warm air downward in winter. All ceiling fans have a switch on the side of the motor housing to control the direction that they will turn. Home Depot has a good article on ceiling fan direction.

Personal Fans: In addition to ceiling fans, smaller desk fans or free-standing floor fans can also help improve the cool feeling that you seek inside your home. This might be especially helpful in areas where more heat is generated, such as the kitchen or in a room where exercise equipment is located. Another good option in dry climates is a personal evaporative cooler. We’ve reviewed the best of them, and you can learn more here.

Windows: Opening windows at night when the outside temperature is lower than your inside target temperature will accomplish two things: It will allow cooler, fresh air into your home, and it will keep your AC from running. Be sure to close the windows first thing in the morning to prevent the house from warming up again and causing your air conditioner to run longer to correct it.

Pro Tip for Humid ClimatesShutting down the AC and opening the windows will let a lot of moisture into your home, even if the air that brings it in is cooler. If you live in a humid climate like the US Southeast and Mid-south, this might not be a great idea. Experiment with opening windows on cool evenings. If your home is comfortable and your energy costs drop, go for it.

Whole House Fans are Awesome: If temps drop significantly at night where you live, then a whole house fan, aka attic fan or whole-house fan, can be a game changer. Once the outside air is 5-10 degrees cooler than your indoor air, open the windows and turn on the attic fan / whole house fan. It will pull in cool air through the windows and exhaust warm indoor air into the attic or straight out of your home, depending on installation. 

For this to be effective when pushing air into the attic, your attic must be properly vented. If this sounds like a good idea in your location, consider having an HVAC pro check out your attic and advise you whether a whole-house fan makes sense for you. Keep in mind that a whole house fan can’t dry the air, obviously, in the same manner that central air conditioning does.

More Money-saving Comfort Tips

Save money, be more comfortable. That’s a win-win!

Dress to be Cool – Literally

Wearing light, loose-fitting clothes while inside the house will make you feel cooler than those made of heavier fabrics that cling to your skin. This is actually true whether you are indoors or outdoors because clothes made of light fabrics and that fit loosely allow the moisture on your skin to evaporate more readily. Regardless of what you wore while you were away from your home, change into clothes that will improve your “coolness” at home.

Humidity = Sticky, Muggy, Clammy - And How to Beat It

Maintaining a proper humidity level  in your living space will enable you to maximize how cool you feel. Several environmental as well as health agencies say that a humidity level of 30 to 50 percent will keep you more healthy and comfortable and also prevent mold and pests during the summer months. Air conditioners are designed to not only cool, but to also remove moisture from the air. Unless you have a device to monitor the humidity, however, you will not know if your AC system is reaching and maintaining that 30-50% level. These devices are called, “hygrometers”, and can be purchased at many hardware or big box stores quite inexpensively.

Dry your Basement Air

If your home has a basement, the humidity level down there may be much higher than the recommended level. Even if you do not have living space there, that humidity may find its way upstairs and keep humidity levels too high. A dehumidifier can help you achieve lower humidity and make your home feel cooler. A standard size dehumidifier will probably add up to 50 cents per day to your electric bill, but you might consider this a small price to pay for the increased comfort it will bring.

Plan Smart

Watching the weather can be helpful in your overall goal of keeping your home cool in the summer. If you see a heatwave on its way to your area, plan on using your washer, dryer and dishwasher before or after the heat of the day. This might even be a good time to visit your favorite restaurant and not heat up the kitchen at all.

Pro Tip: Some energy providers (electric companies, power companies) offer lower electricity rates for non-peak hours like after dark when ACs aren’t running as much. Check your provider’s website or give them a call to see if they have a “smart meter” option that can lower your energy rates during times of the day when there is less demand on the energy grid.

Did you Know? Dry air is more comfortable than humid air. That’s not a surprise. To that end, make sure to use the exhaust fans in your kitchen when you’re cooking and in the bathroom when the showers are being used. Why? Get the humidity out of the air, which will make the air feel more comfortable.

What Can a Window AC Do for You?

Generally speaking, window air conditioners are not as energy efficient as central air conditioning. However, if you were to turn off your central AC at night and use a window AC in your bedroom on the hottest nights, you might save money on your energy bills. This might be a good option in hot, humid locations like “Hotlanta” (Atlanta) or NoLa (New Orleans) when the nighttime air doesn’t cool/dry much. Window ACs are a little noisy, especially when the compressor kicks on and shuts off, but if you’re an energy miser, this might be food for thought. Read more in our Window AC Buying Guide and Reviews post.

From there, you can look at our reviews of the Quietest Window ACs, reviews of units of various sizes, low-profile window ACs and much more. Yes, Pick HVAC covers it all!

Bottom Line on Comfort and Energy Cost

Finding the best temperature to set your air conditioner on involves more than just picking a number, doesn’t it? This is because there are other things to consider, and several ways to help achieve that “perfect” atmosphere inside your home without resulting in an abnormally high energy bill. By following the above information, you should be better equipped to find what works best for you and your family.

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