Why Is My Air Conditioner Not Cooling House Below 80 Degrees?

It can be frustrating to have your thermostat set at a temperature below 80 degrees, but the temperature in your home won’t reach any number below 80. There are a few reasons that your air conditioner might be having problems. 

Before we get into those reasons, we need to understand what an air conditioner can and what impacts your unit’s ability to reach the temperature you have set. 

How Much Can an Air Conditioner Drop the Temperature in Your Home?

Residential air conditioning units, like the one you have installed at your home, can reduce the temperature in your home by around 20 degrees maximum. You can set your thermostat to a temperature that is less than that 20-degree drop, but it cannot be set higher. 

That means if it is 100 degrees outside, your air conditioner only can cool your home down to 80 degrees. If you notice your air conditioner is not cooling your house to the temperature you have it set at, the outside temperature might have some part.

What Factors Impact Your Air Conditioner’s Temperature Drop?

1. Lack of Maintenance

Much like a car, your air conditioner needs regular maintenance to operate how it should. If it is not provided with this necessary maintenance, minor problems can turn into massive problems that can seriously decrease your unit’s efficiency.

You should schedule yearly maintenance for your air conditioner to keep it in the best condition possible. This will help your air conditioner’s performance in the long run and short run. It will also extend the life of your unit to the maximum length possible.

2. Outdoor Heat

If it is hot outside, it is normal for you to want to turn your air conditioner as low as it will possibly go. When it doesn’t reach the temperature you are hoping for, it can be frustrating. However, air conditioners only can cool your home 20 degrees lower than the temperature outside.

3. Home Size and Direction

When you live in a large house, it will take longer to cool it down. The larger the home, the harder the air conditioner will have to work. Even if you have a suitable air conditioning unit for your home’s size, it might take longer to pump cool air throughout the home.

It is also important to take into consideration which direction your house is facing. Houses that are facing west and south are more likely to have a harder time cooling down due to being exposed to the sun for long periods of time throughout the day.

4. Windows

Heat can very easily pass through windows into your home. This is especially true for windows that have a lot of exposure to sunlight during the day. If you have many windows in your home, it might be harder to cool down your space. To prevent this from being an issue, consider shades over the windows.

5. Appliances

The appliances in your home, such as your oven, dishwasher, and dryer, all have an impact on the temperature in your house. It would help if you tried only to use these appliances when the temperature is already cool, and you are not trying to lower it. 

6 Reasons Why Your Air Conditioner is Not Cooling Below 80 with Solutions

1. Dirty Air Filter

Air filters are there to trap any pollutants that are in the air before they enter your air conditioning system. Over time, that means your filter will get dirty and have build-up stuck to it. If your air filter is dirty and hasn’t been replaced, it can limit your unit’s cooling power. 

To fix this problem, check on your air filter. If it looks incredibly dusty, it’s time to replace it. To prevent this from happening again in the future, check the filter once a month and replace it when it is dirty.

2. Blocked Condenser

The condenser is there to collect the heat that is inside your home and release it outside. For this process to take place, the condenser needs to have room to breathe. If the condenser is blocked, all of the hot air will go back into your home.

To fix this issue, you will need to inspect your condenser. Make sure there are no plants around that might be invading the space of your condenser. You will also want to keep an eye out for spare leaves or dirt build-up. If you notice your condenser is dirty, rinse with a gentle hose.

3. Refrigerant Leak

Refrigerant is the chemical inside your air conditioning unit that keeps your house cool. If there is a leak and the unit has a low refrigerant level, this will limit your unit’s cooling capability. You will easily tell if you have a refrigerant leak by checking out a few things.

First, take a look at the refrigerant lines to see if it is icy. Check your evaporator coil to see if it is frozen. Listen for whistling or hissing noises coming from the refrigerant lines. You should also pay attention to your electric bill and whether it is higher than normal.

If you notice any or all of these signs, you will want to have a professional come out to find and repair the leak. They will also be able to fill your unit with more refrigerants.

4.Too Small of a Unit

If you have an air conditioning unit that is too small for your home, it will have a tough time reaching the temperature you have set. Air conditioners are sized by tons, and the larger the unit, the more cooling power it will have. If you notice your unit is constantly running, but your house isn’t cooling, your unit might be too small.

If you suspect that your air conditioning unit’s size is not compatible with your house, you should have a professional take a look at it to make sure. If they agree that it is too small, you will need to upgrade your unit. The professional will be able to recommend the right size needed.

5. Leaky Ducts

Air ducts are what deliver cool air throughout your home. If there are leaks anywhere in the ducts, cold air will escape and will not be delivered throughout the house as expected. This means your home will never be able to reach the temperature you have set.

You might determine where the leak is on your own, but it is recommended to have a professional inspect your ductwork for leaks throughout the home. They will also be able to provide the repair service needed to fix the problem.

6. Unit is Too Old

As an air conditioner ages, its performance will start to decrease. If you have an older unit, it might not have the capability to cool your house as well as it used to. 

If your air conditioning unit is more than 10 years old, it’s probably time to have it replaced. A newer unit will not only cool your home better, but it could save you as much as 20% on your electric bill.

If you have an air conditioning unit that you know is more than 10 years old, you should have it replaced. Have a professional out to take a look at your unit. They will be able to replace it for you and get your house cooler than 80 degrees.

How to Use Your Air Conditioner’s Drop to Choose Thermostat Settings

Air conditioning units can drop the temperature in your home up to 20 degrees lower than the temperature outside. If you are wondering what temperature you should set your thermostat to, it is pretty simple!

All you need to do is take a look at the temperature outside. For example, if it is 90 degrees, you should not set your thermostat any lower than 70 degrees. This will prevent your air conditioner from running non-stop, trying to reach a temperature that it can’t. 

If it is really hot outside and trying to get your house to cool off as low as possible, try covering your windows to keep the sun out. You might also want to invest in some fans to run as well. These will help cool your home lower than what your air conditioner can handle.


It can be annoying when you are trying to cool your house, and it won’t hit the temperature you set on your thermostat. If you have noticed that your air conditioner will not cool your home below 80 degrees, there are a few reasons that might be. 

The first thing you need to keep in mind is that an air conditioner can only cool your home 20 degrees less than the temperature outside. If the outside temperature is not the problem, it might be with the unit or the ductwork.