Why does my AC take hours to cool?

Author: Zack Wunsch  |  Last update: Monday, December 15, 2025

This could be due to several factors, such as a dirty air filter, coils, or refrigerant leak. If your air conditioner isn't operating at peak efficiency, it will take longer to cool your home. Finally, it could be that the temperature outside is too hot for your air conditioner to keep up with.

Is it normal for AC to take hours to cool?

The AC System Has a Dirty Air Filter

A dirty air filter is one of the most common reasons why an air conditioning system takes a long time to cool a home. The filter is responsible for removing dust, pollen, and other airborne contaminants from the air.

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

On average, this process takes roughly two and a half to three and a half hours. However, this is not a one-size-fits-all answer. The cooling duration can be swayed by various elements, such as the efficiency of your HVAC system, the home's insulation quality, and even external factors like direct sun exposure.

Why is it taking so long for my AC to cool down?

Dirt, dust mites, pet dander, debris, and other buildup can get trapped in your AC filter. Once this buildup reaches a certain point, it reduces your air conditioner's efficiency. This makes the unit work harder to cool down your home, which is why it takes longer to reach the desired temperature.

How long should it take AC to drop 1 degree?

Typically, it takes about an hour for an average-sized air conditioning unit in typical conditions to lower room temperature by one degree Fahrenheit. But remember, 'average' doesn't mean 'always'. Like people, every AC has its personality – some are sprinters while others prefer marathons.

Why my AC stops cooling after some time?

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 20 degree rule for air conditioners?

Simply put, it means you should never set your thermostat for a temperature more than 20 degrees cooler than the outside air. Why not? Most air conditioning systems can only handle a 20-degree difference between the outside and inside air temperatures.

How can I speed up my AC cooling?

Even a small gap of space can allow enough heat from outside to come in and drastically change the temperature of a room.
  1. Close the Blinds. One of the main hindrances to keeping a room cool is too much sunlight being allowed into the room. ...
  2. Close Doors. ...
  3. Turn Down the Thermostat. ...
  4. If the Room Still Doesn't Seem to Cool Down.

How long should it take for AC to get cold?

Most central air conditioners can cool a moderate-sized (3 to 4 bedroom) home by about 5 degrees every 3 hours. This means while it can take no more than a couple hours to lower the temperature to a comfortable range in the fall or autumn, it can take much longer in the summer.

Can I clean my own AC coils?

While there are a number of commercially available coil cleaning solutions on the market, air conditioner coils can be cleaned with a solution of a mild household detergent and water. The detergent and water mix is applied to the coil using a low-pressure sprayer.

How fast should an AC unit cool a house?

As a general rule of thumb, a well-maintained air conditioning unit should be capable of lowering the temperature by approximately 20°F within the first hour of operation. However, achieving the desired temperature may take longer depending on various variables.

Why does my house take so long to cool down?

Dirty Air Filter

Over time, the filter becomes clogged with dust, pet hair, and textile fibers, reducing circulation. Besides making your air conditioning system take more time to cool down the house, this problem can also produce larger energy bills, additional wear and tear, and overheating.

How to clean an evaporator coil?

Steps For Cleaning Evaporator Coils

Remove the access panel to expose the coil. If the coils are coated with dirt or lint, vacuum them with a soft brush attachment. If the coils are coated with oil or grease, clean them with a mild detergent and water solution and rinse. Be careful not to splash water on insulation.

Is it OK for my AC to run for hours?

The truth is that your AC unit can be "on" for long periods. Cooling a building requires the AC unit to run throughout the day to keep your home or commercial space at a comfortable temperature all day and night. It's normal for an AC to run for multiple hours per day.

How to check refrigerant level in AC?

Steps for Checking Refrigerant Levels
  1. Turn Off the AC and Remove the Cover. Turn off the AC unit and remove the cover to access the refrigerant level gauge or gauges.
  2. Locate and Remove the Access Panel. ...
  3. Attach Refrigerant Pressure Gauges. ...
  4. Interpret Pressure Levels. ...
  5. Add Refrigerant (if Necessary)

Why is my AC struggling to cool my house?

Proper airflow is crucial for an AC system to cool your home efficiently. Several factors can compromise airflow, including blocked or obstructed vents, closed or incorrectly adjusted dampers, and dirty or obstructed evaporator coils. These issues restrict the air's flow, reducing the system's cooling capacity.

Why does AC take too long to cool?

A clogged filter is the most likely reason an AC system needs more time to cool the house. The job of a filter is to catch airborne particles that could harm your HVAC equipment. More effective filters even trap microscopic airborne allergens to improve indoor air quality.

Why is my AC not getting very cold?

There are many reasons your AC might not be cooling your home properly. The solution could be as easy as flipping a switch on your thermostat, cleaning a dirty air filter, or clearing debris away from your outdoor unit. There are also more complex problems that may need the help of a professional.

How long does it take for freon to settle in an air conditioner?

Freon settles in an air conditioner in a matter of minutes. Though, it depends on the type of air conditioner too. If the air conditioner is portable, it takes about 5-30 minutes for the Freon to settle. This time must be dedicated to the appliance for it to function properly.

Why my new AC is not cooling fast?

A clogged filter restricts airflow, impairing the AC's ability to pull in warm air and release cool air. Making sure to clean the filter at regular intervals is essential for optimal performance. Another possible reason could be a dirty condenser coil.

Does turning down the AC make it colder faster?

Setting your thermostat low doesn't cool your home faster

“People think, 'If I make the thermostat set point 60, I'll get more cooling than a set point at 70,' but that's not correct,” Liu said. “You get the same amount of the cooling.”

How can I cool my AC faster?

Turn extra lights off to reduce the heat level in the room so that the AC has to work that much less. Switch on the AC before it gets too hot, so that it does not have to overwork to cool the air. Turn off the exhaust fans in your kitchen and bathroom when the AC is on, so that the cool air is not sucked away.

How cool should my house be if it's 90 outside?

What should my AC be set at if it's 90 degrees outside? If the outdoor temperature is 90 degrees, it's recommended to set your thermostat between 75-78 degrees.

Why won't my AC get colder than 73?

A dirty air filter

Your air filter is designed to trap contaminants in the air before it gets pulled into the AC system. But over time that means that your filter gets dirty and clogged. And if a dirty filter isn't replaced, it can seriously limit your AC's cooling power.

Do you turn the air conditioner up or down to make it colder?

HVAC experts will tell you all the same thing: turning your thermostat to a lower setting DOES NOT cool your home faster. Setting your thermostat to 65 degrees will not get your home cooler faster than setting it at 73.

Previous article
What not to do with frozen pipes?
Next article
How to get dead rat smell out of vents?