The best temperature for AC in the summer


Where would we be without air conditioning? There are many places in the US where life would be pretty unbearable in the summer without AC. When temperatures head toward 90℉ or over 100℉, having a good AC system in your home makes a big difference. And if that temperature is twinned with high humidity, AC is the only thing that makes doing anything more than sweating possible.

But that comes at a (literal) cost. Heating and cooling are the most power-hungry parts of running a home, so you want to get it right; throwing money away is never a good idea. So what temperature should you set on your AC to give you a comfortable temperature and not hemorrhage dollars? Also, what can you do to keep those electric costs down?

What is the best temperature for AC in summer?

Saying the best AC temperature in summer is the one that suits you may sound like a cop-out, but it carries a lot of truth. Everyone is different; what’s too warm for some is a little cool for others. The environment you live in also has a bearing. If you live in Texas, your idea of hot may be rather different from a native from Colorado. If a New Yorker visits Italy in the fall, they might feel shorts and a t-shirt are the way to go, while the Italians are wearing jackets and coats.

Even the experts disagree; one will say 72℉ is perfect, another 78℉, and a third, something in between. Only you can say with certainty what temperature feels best to you, which may change with the weather outside or even your age. However, somewhere between that range is often best.

What is the ideal temperature for AC?

Most people like to set their AC so that their house's temperature is somewhere in the 70℉-80℉ range. This is cool enough to work or relax without being so cool you feel the need for an extra layer to be comfortable. Keeping the temperature in the 70s will allow your AC to be in its sweet spot, too, though that does depend on how hot it is outside. The harder an AC system works, the more power it will use, and the more it’s going to cost you when the bill comes in.

Is 72℉ a good temperature for air conditioning?

The question is, what temperature to put ac on in summer? Often 72℉ is quoted as the ideal AC temperature setting in summer. While 72℉ is certainly a temperature that many will feel comfortable with, it might not suit you and anyone else who shares your living space.

Even if you feel good at 72℉, it might not be what you need to set on your thermostat. Other factors come into play. For instance, the US Department of Energy estimates that fans play an important part in making you feel cool. The DOE suggests that ceiling fans make about 4℉ difference in how you feel. If you use fans, you may be able to set your AC to 75℉ or 76℉, reducing energy consumption, and still enjoy a 72℉ environment.

So would 75℉ be a good temperature for air conditioning? If you want to enjoy a 72℉ living temperature and are using ceiling fans or window fans, then setting your AC at 75℉ makes sense. 75℉ is cheaper to achieve than a lower temperature, and the fans' cooling effect will give you a 72℉ environment.

Is 78℉ too hot for a house? The simple fact is that the warmer your house is in summer, the less it’s going to cost you. Many people find that a temperature approaching 80℉ is absolutely fine, so long as the humidity is kept in check. Humidity has a massive effect on how hot and uncomfortable you feel. Don’t forget that one way an AC works is by reducing humidity. If your AC system is well maintained and efficient, it will keep the humidity low, and a higher temperature will feel fine.

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

In many states, it’s not uncommon to see temperatures reach over 100℉ in summer for days on end. Trying to keep indoor temperatures to 72℉ or less will keep your AC working hard and consuming a lot of energy. Most AC systems are designed to reduce temperatures by around 20℉, and attempting a 30℉ reduction may be stretching its capabilities. A dehumidified 80℉ is livable for most people, and if you have to go outside, it won’t come as too big a shock.

Even running the AC at 80℉ will require it to be looked after and running at peak efficiency. Having the system serviced before the summer heat comes around is a wise precaution.

Which mode is best for AC?

AC units vary in their flexibility and the modes they offer. At the very least, apart from temperature control, they will offer different fan settings. You should select high for the most effect on a normal warm day. However, if humidity is the problem, you are better off choosing slow, which allows the AC to remove the moisture more efficiently.

For many units, the cool mode is the default setting for cooling a room and allows the fan to run continuously while the compressor turns on and off to maintain the temperature. Some systems have a fan mode which just provides air movement rather than cooling. This may be useful in some situations but not in the summer when you are looking to lower the temperature.

Some air-cons offer a dry mode where it simply operates to dry the air rather than cool it. This is of limited use in hot weather but might be employed at other times. You should remember that while an AC unit does dehumidify, it is not a replacement for a dedicated dehumidifier which has much more capacity than an AC.

Most modern ACs include an energy saver mode in their features. It is certainly a good idea to employ this mode when you can, as it offers real energy savings. However, some will find the repeated switching on and off of the fan irritating.

If your AC includes a sleep mode, it allows the temperature to rise a little during the night when your metabolism is slower, and the need for temperature reduction is not so acute.

How many hours should AC run per day?

When the outside temperature is high, you may find your AC runs pretty much 24 hours a day. However, if it does this when the weather is not terribly hot, it is probably because it doesn’t have sufficient capacity for your home or has a fault. During milder weather, you might expect an air-con to run in perhaps 12-15 minute periods a couple of times an hour.

How can I lower my AC bill?

ACs do tend to use a lot of power, but there are ways to reduce the bill:

  • Use a programmable thermostat so that the AC is used efficiently, allowing your home to be warmer when you’re not there but turning on 30 minutes before you come back so that the temperature is perfect when you arrive.
  • Set your thermostat a few degrees warmer – every degree will reduce the time the AC operates.
  • Check that the AC is running efficiently and that it’s topped up, the ducts are sealed, and the filters clean. When an AC is running optimally, it costs less to run.
  • Make sure your home is sufficiently insulated. It is far easier to maintain the temperature of a well-insulated home.

Can I run my AC 24/7?

When it is super hot, running your AC all day, every day may be the only way you can maintain a comfortable temperature. However, if it continues to operate like this even when the outside temperature drops, you should have it looked at as it is like something is amiss or that it is undersized for the area of your house.

Is 78℉ the best temperature for AC?

Both the DOE and Energy Star suggest that 78℉ is the ideal setting for an AC unit, although they advise increasing that during the day and when you are asleep. In fact, they recommend that you adjust the temperature up by as much as 7℉ during the daytime and 4℉ at night. With fans installed, that is an excellent place to start, but you may want to diverge from that figure depending on personal preference and the relative humidity. If you do live in an area that experiences high humidity, you may be wise to install dehumidifiers in addition to your AC and fans. Most of us can stand higher temperatures providing humidity remains low.

Turning on your AC and forgetting about it is not the smart option if you want to save energy and lower your electric bill. Asking what temperature should the AC be in the summer, keeping it well maintained, in the right mode, and with the thermostat set carefully will significantly reduce the amount you pay for power and reduce your carbon footprint, too.

At Inspire Clean Energy, we don’t want you to waste electricity or make those energy bills larger than they have to be. By paying attention to your AC in summer, you can minimize waste and cut those bills. If you know you can’t reduce energy consumption in the summer but also don’t want to see your carbon footprint grow significantly, switch to a green energy plan.

Our clean, renewable energy plan provides you with 100% clean, renewable energy, so you can rest assured that your energy consumption isn’t contributing to global warming and other negative environmental effects. Click here to see unlimited energy plans today or find out more.