Why is My AC Taking So Long to Cool My Home? A Portland Tech Explains

Feels like your AC is taking forever to cool your house?

We’ll help you troubleshoot this frustrating problem.

One reason your AC could be taking a long time to cool your home is that it’s just a really hot day. When outside temperatures are especially high, your AC will naturally have to work longer and harder to cool your home.

Not especially hot outside? If it’s a normal day and your AC is taking a long time to cool your home, you may have one of the following problems:

  • A dirty air filter

  • Dirty condenser or evaporator coil

  • A refrigerant leak

  • Leaky ducts

  • An old AC

  • Improper schedule programmed on thermostat

Let’s look at each of these problems in more detail below.

Want a professional to inspect your AC and repair the problem? Call us at 503-538-1950 or schedule an appointment online today and we’ll send one of our trained AC technicians to help.

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Problem #1: A dirty air filter

One of the most common reasons why an AC takes longer to cool your home is because of a dirty air filter.

You see, when a filter becomes clogged with dirt and debris, it restricts the amount of air the AC can bring into the indoor unit to be cooled. As a result, the AC will have to run longer to bring in sufficient air, which ultimately means it will take longer to cool your home.

Besides longer run-times, a dirty air filter can also lead to problems such as:

  • Higher energy bills

  • Extra wear and tear on AC equipment

  • Overheated components

Solution: Go to your air filter and check to see if it’s dirty. If you see that it’s clogged with dirt and debris, replace it with a new one.

Clean air filter versus clogged air filter

Clean (left) vs dirty (right) air filter

We know it’s easy to forget about your air filter, so we recommend setting a reminder to check it every month. That way, you can replace the filter before it gets too dirty.

Problem #2: Dirty condenser or evaporator coil

Your AC consists of two major components: an indoor and outdoor unit.

The indoor and outdoor units of a central air conditioner

Inside the indoor unit, warm air is cooled by the evaporator coil. Circulating inside the evaporator coil is a cold liquid called refrigerant. Refrigerant absorbs the heat from your home’s warm air and carries it to the outdoor unit.

When the refrigerant reaches the outdoor unit, all of the heat absorbed by the refrigerant is dumped into the outdoor air via the condenser coil. After the heat is dumped outside, the refrigerant cools down and gets sent back to the indoor unit, where the cooling process repeats.

However, if either the evaporator or condenser coil is dirty, the entire cooling process is slowed down because it makes it harder for the refrigerant to absorb or release heat. This could explain why your AC is taking so long to cool your home.

Solution: Contact a professional to inspect the indoor and outdoor coils. If they are dirty, an AC technician will have the proper tools to clean them.

Problem #3: A refrigerant leak

Above, we explained that refrigerant is the liquid substance that’s responsible for removing heat from your home’s warm air.

Normally, refrigerant circulates between the indoor and outdoor units in a closed loop via copper lines. However, if the copper lines or one of the coils develops a leak, your AC will lose refrigerant, which means your system can’t absorb and release as much heat. The end result is that your AC will take longer to cool your home.

Other signs that indicate your AC may have a refrigerant leak include:

  • A hissing or bubbling sound near the outdoor unit or refrigerant lines

  • Ice buildup on the refrigerant lines or evaporator coil

  • Higher humidity levels indoors

Solution: If you suspect you have a refrigerant leak, you’ll need to contact a professional ASAP for assistance. A technician will find the source of the leak, repair it, and refill your system with the correct amount of refrigerant.

Problem #4: Leaky ducts

Your home has two types of ducts:

  • Return side ducts, which carry warm air into the indoor unit to be cooled.

  • Supply side ducts, which carry cool, conditioned air back into your home.

If ducts in either location are leaky or disconnected, then ultimately your AC will have to work harder and longer to keep your home cool.

Here’s how:

Supply-side leaks cause conditioned air to escape out of the ductwork. While the temperature of the air coming out of the vents may not necessarily be lower, the airflow will feel weaker, which makes it seem like your AC is taking a long time to cool your home.

Return-side leaks make it harder for your AC to pull in sufficient air to be cooled. As a result, your AC will run longer to keep your home at your desired temperature.

Other signs that you have leaky ducts include:

  • Uneven temperatures throughout the house

  • Excessive dust coming out of the supply registers

Solution: Contact an HVAC specialist to inspect your ductwork. If it turns out you have leaky ducts (many homes do), the professional will need to seal the ducts, or, if the damage is severe, replace the ducts.

Problem #5: An old AC

Finally, your AC could be taking a long time to cool your home because it’s getting old. Air conditioners are not built to last more than 10 to 15 years. As an air conditioner ages, it loses efficiency and will naturally take longer to keep your house cool.

Solution: If your AC has passed its 15th birthday, it may be time to consider a new air conditioner. Contact a trusted HVAC specialist for an estimate on the cost to install a new one.

Problem #6: Improper Schedule Programmed on Thermostat

Your air conditioner may not be designed to lower the air temperature on the hottest days, but simply to maintain a comfortable temperature. Programming the correct schedule on your thermostat can help keep your home cooler.

Solution: If you aren’t comfortable programming a schedule or aren’t familiar with your thermostat’s programmable features, contact a professional.

Need an AC repair from a Portland pro?

Schedule appointment

Call us at 503-538-1950 or schedule an appointment online today to schedule fast, same-day service. Our NATE-certified technicians follow the highest industry standards when it comes to AC repairs. When you hire Four Seasons to repair your air conditioner, you can count that the job will be done correctly—the first time.

Learn more about what to expect when you hire us by visiting our AC repair service page.

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