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Reasons Your Air Conditioner Isn’t Working Like It Used To

Air conditioners typically have a lifespan of between 10 and 12 years. At that point, it’s not surprising for the unit to falter. But when a newer air conditioner is not working as well as it used to, it means something’s going on behind the scenes.

Below, we’ll point out some of the possible reasons why an air conditioner is not working as well as it used to.

Common Air Conditioner Problems

These are among the most common complaints people have when we get a call for air conditioner repair in Toronto. Often, it’s a combination of issues that seem to have gotten worse over time.

  1. Air conditioner not cooling effectively (or not at all)
  2. Some rooms are colder than others
  3. Air conditioner turning on and off frequently
  4. Air conditioner running all the time
  5. Air conditioner frozen

1. Air Conditioner Not Cooling Well or Not Cooling at All

Does the central AC that kept you comfortable last summer seem to be on vacation this year? Numerous problems can result in subpar performance.

  • Restricted airflow
    There should be a clear passage for air to travel from the supply vents to the evaporator coil and back into the home through the air registers. The air conditioner won’t do its job as well if there’s something in the way, be it a clogged air filter, weeds and debris in the outside condenser unit, furniture blocking the supply vents, or unclean air ducts.
  • Thermostat issues
    Check to confirm that the thermostat is in working order. It may simply require fresh batteries, or it could need replacement.
  • Frozen evaporator coils
    The evaporator coil cools and removes moisture from the air to manage the temperature and humidity inside the home. When the coil freezes over, warm air cannot pass through it to cool down. We cover what to do if your air conditioner is frozen in the section below.
  • Low refrigerant
    When an air conditioner is low on refrigerant, it can cause a whole host of problems, including poor performance. If the problem persists after replenishing the refrigerant, it could indicate a leak — which is a problem that necessitates an air conditioner repair call.

2. Some Rooms Colder than Others

Central air conditioning should maintain an even temperature throughout the home. It’s fair to expect small differences (rooms furthest from the AC unit will be slightly warmer, for example), but a significant temperature difference indicates a problem.

  • Air duct leak
    Small leaks in the air ducts can hinder airflow to the entire house, and larger leaks can result in distant rooms being cut off from central air.
  • Thermostat location
    The thermostat acts as a temperature gauge for the entire house. If the environment surrounding the thermostat differs drastically from other parts of the home, it can result in a temperature imbalance.

One solution to temperature differences is a zoning system, which lets you fine-tune the temperature in different parts of the home individually.

3. Air Conditioner Turning On and Off Frequently

Short cycling is one of the most prevalent air conditioner problems. The usual cause is an oversized air conditioner that cools the home too quickly, resulting in a constant on-off cycle. But if your air conditioner used to work fine, it could be a different issue entirely.

  • Thermostat location
    Heat sources near the thermostat can cause the air conditioner to cycle more often than it should. Make sure the thermostat is not in direct sunlight or close to a supply vent. Avoid placing heat-emitting electronics, like TVs, near it.
  • Thermostat settings
    If you use a smart or programmable thermostat, check to see that it’s set to adjust on a schedule you desire.
  • Low refrigerant
    Low refrigerant causes pressure in the system to drop. The compressor unit, which supplies refrigerant to the evaporator coil, will usually shut off automatically if the pressure drops too low. Afterwards, the pressure will rise again, creating a rapid On/Off cycle.

4. Air Conditioner Running All the Time

A central air conditioning unit is designed to shut off once the home reaches the desired temperature set on the thermostat. There are several possible reasons why this isn’t happening.

  • Broken contact
    The contactor is a switch in the outdoor compressor unit that tells the air conditioner when to shut off. If the contactor is broken or obstructed by debris, the unit will run non-stop.
  • Not cooling effectively
    Another reason why the air conditioning might constantly be running is that it cannot meet the home’s cooling demand. See the section above on why an air conditioner might not be cooling as well as it used to.

5. Air Conditioner Frozen

You know something’s not right when you find a sheath of ice on your air conditioner in the middle of summer. Turn off the unit to let it thaw, then consider the following possible culprits.

  • Restricted air flow: Ice forms when warm air can’t reach the evaporator. This could be because the air filter is clogged, the blower fan is malfunctioning, or something is blocking the supply vents.
  • Low refrigerant: When pressure drops due to the low refrigerant, the remaining refrigerant expands, causing cooler-than-normal temperatures inside the system.
  • Low outdoor temperature: This isn’t a likely concern in the summer, but it’s something to keep in mind when fall comes around: running the air conditioner when the temperature drops below 18°C can turn your AC into an icebox.
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