Does Outside Temperature Affect Air Conditioners (Efficiency Explained)

Air conditioners help to keep you cool in hot temperatures by regulating the air in your home. Even though they work to cool you down, different conditions can impact air conditions in different ways, and even the best air conditioners can be affected by the outside temperature.

This guide will help you understand how air conditioners work and how different temperatures can affect them.

How Do High Temperatures Affect Your A/C Unit?

Naturally, air conditioners are used more frequently in the summer months, so it’s important to know how high temperatures might impact them. Your air conditioner is designed to take the air temperature 30 degrees Fahrenheit lower than the outside temperature.

On an average day, that’s probably enough, but if it’s really hot outside, then you’ll likely want the indoor temperature to come down more than 30 degrees, and your AC unit may struggle. You’ll need to accept that your air conditioner can only do so much on the hottest days of the year.

When it’s really hot, your AC unit will work harder to cool the air. This puts more strain on the air conditioner and can cause the components to wear out more quickly.

In hotter temperatures, you should expect the air filters to become clogged more often, the exterior fan to collect dirt and debris more quickly, and it may cause older units to malfunction.

Most air conditioners are designed to work in up to 100-degree Fahrenheit conditions. If it gets much hotter than that, you might start to experience issues.

How Temperature Affect AC Unit

How Does Running Your AC In Cold Temperature Affect It?

Even though you’re less likely to use your AC in winter, you can still use them if you need to, so it’s useful to understand what the impact of cold temperatures can be.

Frozen Window Type Air Conditioner

Most AC units will run normally until it gets to about 60 degrees Fahrenheit, but you can get some specialized air conditioners designed for colder climates. Most home equipment has a minimum temperature it can run at, and for AC units, it’s typically about 60 degrees Fahrenheit.

Most mini-split AC units have an outdoor unit that connects into your home, and this may be susceptible to freezing if it’s too cold out.

In very cold conditions, you might experience the freezing of refrigerator coils, which stops the unit from working correctly, the thickening of lubricant in the unit, which can stop components moving as they should, and other damage to components that move.

All of this makes your AC completely inefficient or just downright unusable if it gets too cold.

Other Factors That Affect Air Conditioner’s Efficiency

So now you know that temperature can have an impact, but that’s not the only factor. Here’s a quick breakdown of the other factors to be aware of:

SEER Rating

SEER stands for seasonal energy efficiency ratio and is basically the indicator of how energy efficient your AC is. The higher the number, the more energy-efficient they are, and you’ll get more cooling power from less electricity.

Modern AC units are required to have a SEER rating of 13 or more, but some older models have less than that. The lower the SEER rating, the higher your energy bill and the less efficient your AC unit is.


It’s crucial that you find an AC unit that matches the size of the room it’s in. If it’s too small, then you won’t feel the cooling action, and if the AC is too large, then it can use too much energy.

Either way, this makes your AC less efficient, and you need to find an air conditioner that strikes the right balance. Measure your room accurately before you start searching for a new AC because most models will give a clear indication of the area they can work within.

Lack Of Maintenance

A poorly maintained AC unit is far less efficient. This is because it has to work harder, and there’s a greater risk it will just break down. Your AC unit, like other home equipment, needs to be checked, cleaned and serviced regularly if you want it to continue working efficiently.

Clogged Leaking Ducts

If you find your AC unit isn’t performing efficiently, then you should check the ducts. This is the route that cool air is transported back into your home, and if it’s blocked or leaking, it won’t have the proper cooling effect.

Repairing gaps and removing blockages is an important part of maintaining your machine.

Low Thermostat Setting

Your air conditioner will be impacted by your thermostat setting. If you set it too high, then your AC unit can struggle to operate effectively, and you essentially have two bits of equipment working against each other.

Try to set the thermostat to a reasonable level to help protect your AC unit.

How Can You Help Your AC During Hot Weather

Your AC is vital when it’s hot out, and it’s important that you take action to keep it running properly. This will help to cool your home but also protect the AC unit so that it has a longer lifespan. Here are some things you should try and do to protect your air conditioner:

Set The Unit Correctly

In hot weather, make sure you aren’t expecting too much from the air conditioner. Don’t set it more than 20-30 degrees below the outdoor temperature, or it may damage itself by pushing too hard.

Clean The Filter

Make sure your air filter is clean because a dirty filter can make it work a lot harder. You should check it at least once and month and look to replace it every 2-3 months. It’s worth replacing your filter just before the summer weather kicks in.

Related Article How To Clean An AC Filter

Clean Dirty Air Filter

Perform Regular Maintenance

Undertaking a full inspection and routine maintenance on your AC unit every month will help to protect it. This will help you identify any issues that may impact the overall performance of the conditioner and take action before the hot weather makes the problem even worse.

By taking the time to monitor and maintain your AC unit properly, you can add years to its lifespan. This helps to keep you cool for longer and gives you better value for money.

People Also Ask (FAQ)

Why is my air conditioner running but not lowering the temperature?

This is typically because your condenser coil is blocked or damaged, and therefore the air isn’t being cooled appropriately. It’s worth opening up the unit to check and see if it needs to be replaced. If you’re unsure, then you might need to consult a professional.

What temperature should I set my air conditioner on in summer?

Your AC unit should be set at about 20-30 degrees Fahrenheit less than the temperature outside.

What is the average temperature of an air conditioner?

Air conditioners are generally set between 72- and 78-degrees Fahrenheit as this is considered the optimal ambient temperature of a room.


Air conditioners help you control your home environment. High and low temperatures can impact the effectiveness of an air conditioner, and it’s important to understand what could go wrong so you can take preventative action.

Most air conditioners will work really well at 60-100 degrees Fahrenheit, so if you can keep them in this sweet spot, you’ll get the most benefit from them.

Hopefully, this article has given you some useful information about the limitations of air conditions and helped you understand how to protect them from outside conditions.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.