Read on to learn more about the common problems you should know about, so you can take the appropriate action.

There are three possible problems when your AC is not cooling enough:

Space and usage issues

If something in your environment increases the load on your system or keeps it from working properly, your HVAC will not cool well. Once you identify the issue, this problem is often easy to correct.

Equipment repair and maintenance issues

If your system is old or has not been regularly maintained, it may need fixing or tuning up to work as it should.

Issues with the design and/or capacity of your system

If this is why your AC is not cooling effectively, you may need some design changes or even a system replacement.

Space issues and your AC load

1. Blocked Registers and Vents

This problem happens all too frequently in both homes and office spaces. Furniture gets moved so that it blocks AC registers or vents. Especially in office spaces, people even close or block vents intentionally. In fact, it’s one of the most common results of thermostat wars that happen when some workers are too hot and others are too cold.

This could very well turn out to be the reason your AC is not cooling, and it’s an easy fix. Take a walk around your space, and check all the vents and registers to make sure they are open and accessible. (If they are open, but your AC is not blowing cold air, check the next section for a solution.)

2. Too Much Sun

Do you have lots of south and west-facing windows? Sun-worshippers may prefer to leave them uncovered, but all that hot sun is adding a significant load to your AC. If your AC is not cooling enough, try installing blinds or shades that you can close during the hottest part of the day.

3. Too Much Humidity

Sometimes it’s not the temperature but too much humidity that makes it feel like your AC is not cooling. In muggy weather, your AC might not be able to remove enough moisture from the air to make you comfortable, even if the space is at the set temperature.

4. Heat From Lights, Electronics & Appliances

Everything that generates heat increases the load on your air conditioning system. So if your AC is not cooling properly, try shutting off lights, turning off electronics when not in use (like computers and copiers), and running appliances (like dishwashers and washing machines) during non-peak hours when it’s cooler. You can also replace older lighting fixtures with LED lights that produce less heat.

5. Leaky Building

Are you in an older building that’s not so energy-efficient? When air leaks out through old windows, doors, and poorly insulated walls, your air conditioner may not be able to cool sufficiently to compensate.

Fixing this issue can be costly, but there are small changes that can help if your AC is not cooling well due to a drafty space. Try installing weather stripping around the doors and windows, and use window coverings that keep air from escaping.

Issues with the design and/or capacity of your system

6. Poor Air Flow Around The AC Condensor Unit

Air flow is essential to the functioning of your air conditioning system. If your condensing unit (outdoor unit) is covered with leaves or debris, or surrounded by storage items, it may not have sufficient air flow to release heat. Be sure to keep your condensing unit clear if your AC is not cooling well.

7. Low Refrigerant Charge Or Refrigerant Leak

Your air-cooled AC system needs the proper amount of refrigerant in the system (known as ‘refrigerant charge’ or ‘refrigerant top up’) to remove heat from the air in your space. If the AC is not cooling, especially if it seems to happen gradually, your system could have a refrigerant leak.

This commonly happens to older units, or if you have neglected maintenance and your AC coils have developed corrosion or if your AC pipping was loosely fitted along the copper joints. Bring in a qualified HVAC tech to find and fix the leak. Never allow an AC repairman to recharge the refrigerant without fixing the leak, or you’ll have the same problem again.

8. Fan Issues

It bears repeating: air flow is critical to your AC’s ability to cool your space. If one of the system’s fan motors is sluggish, or the fan itself is slowing down because it’s covered in grime and debris, it’s no wonder your AC is not cooling well. A maintenance visit from a qualified HVAC company can fix this problem easily.

9. Clogged Ducts

Here’s another common cause of air flow issues. AC ducts can sometimes accumulate so much dust that prevents enough cool air to freely move through them. If this is why your AC is not cooling well, investing in regular duct cleaning services can bring relief.

10. Not Enough Cooling Capacity

Have you made changes to your space without updating your HVAC system? For example, if you’ve added more space, or significantly added to the number of people in the space, your AC may be too small to handle the new cooling requirements.

How you’re using the space can also change the cooling capacity needed. For example, if you’ve moved into a space that was previously a retail store and now it’s a restaurant, the AC is not cooling because the requirements have increased. You may need to upgrade the system.

HVAC capacity and design issues

11. Too Much Capacity

Surprisingly, the opposite problem can have the same result. If your unit is oversized for the space (which is surprisingly common) it may be turning on and off frequently. That means it never runs long enough to remove humidity, which can make it feel like the AC is not cooling. Believe it or not, you might actually need to downgrade to a smaller unit.

12. Design Issues

If you’ve changed the layout of your space without changing the HVAC design, that could be why your AC is not cooling well enough. Doing a renovation or simply changing an office cubicle layout can change the areas where cooling is needed. Moving or adding ductwork, or adding additional registers can sometimes make a big difference. You’ll probably want the advice of an HVAC expert to sort through all these possible issues and figure out why your AC is not cooling.

If you’ve ruled out all the space-related issues, you may find that your system has issues that need addressing. Especially if your unit is older, you might be facing a repair or replace decision. This can be a tough call: can you gain time by repairing an old system, or are you wasting money on equipment that will break again soon?

When your HVAC system is down, deciding whether to repair or replace can be difficult. You might feel like you need a crystal ball to tell you how much longer your old unit might last and which choice will ultimately be better for your wallet. The truth is, you only need to consider the right facts. Here’s what you need to know and understand:

What types of repair issues are worth fixing

When to replace your HVAC system

Why your unit’s refrigerant may be an important factor

How age & condition impact into your decision

How to calculate potential energy savings

The soft costs you’re probably not considering