Why is my AC air not as cold as it used to be? A Portland tech explains
If you’ve recently noticed that the air your AC is producing isn’t as cold as it used to be, our first suggestion would be to check your thermostat.
Is your thermostat fan set to AUTO? Your AC cools air in cycles. But, if your fan is ON, your AC will constantly blow air throughout your home, even when your AC hasn’t cycled on and that air hasn’t been cooled.
If your thermostat is set to COOL and your fan is on AUTO, but you’re still experiencing issues, you’re likely dealing with:
A refrigerant leak
Dirty air filter
Faulty or broken condenser fan motor
Leaky ducts
In the blog below, we’ll take a look at each of these issues in more detail, so you can get a better idea of whether you’ll need to call a professional or not.
If you need a reliable HVAC partner to accurately diagnose and repair your AC, reach out to us. We’re known for offering the best prices and service, and your experience will be no different.
Reason #1: Refrigerant leak
Refrigerant is the substance responsible for cooling your air. Your AC works by pulling in warm air and by blowing that air over coils that are filled with refrigerant. The refrigerant absorbs the heat from the air and carries that air outside, where that heat is dumped.
If there is a leak in the refrigerant line, your AC won’t be able to absorb as much heat per cycle as it needs to. This can cause the air coming from your AC vents to feel warmer than it should.
If you have low refrigerant levels, that means you have a leak. Refrigerant works in a closed-loop system, so there is no way for it to become depleted unless it’s leaking out of your system.
The solution: Reach out to an HVAC professional. They will be able to diagnose exactly where the leak is coming from and repair the leak before refilling your refrigerant. Refrigerant is a toxic substance, so this is not a repair you’ll want to take on yourself.
Reason #2: Dirty air filter
As we mentioned above, your AC cools your home’s air by drawing in warm air from your home and stripping that air of heat. All of that air that is pulled into your internal AC via your air filter.
If your filter is dirty or clogged, your AC can’t pull in as much air as it needs to per cycle. If your AC pulls in less air, it cools less air and pumps less cooled air throughout your home.
While this doesn’t actually affect the temperature of the air being circulated via your vents, the less cool air coming from your vents, the warmer that air can feel.
The solution: If you feel like the air coming from your AC vents is warmer than it used to be, and/or you notice that there is less air coming from your vents, check your air filter.

If your air filter looks like the filter on the right, it’s time to replace it.
As a rule-of-thumb, it’s best to replace your air filter every 1-3 months (closer to the one month mark during the summer).
Reason #3: A faulty or broken condenser fan motor
The condenser fan is part of your outdoor AC unit that dissipates the heat from the refrigerant into the outdoor air.
If the condenser fan motor is broken or damaged, the fan won’t work properly, which means your AC won’t be able to offload the heat it has carried (via refrigerant) to your outdoor unit.
The less heat your AC can get rid of per cycle, the warmer the air coming from your vents will be.
The solution: Reach out to an HVAC professional. If your condenser fan motor is broken or malfunctioning, a technician will need to repair or replace it.
Reason #4: Leaky ducts
If your return ductwork has leaks or holes in it, it can suck in extremely warm air from unconditioned areas of your home, like your attic, which can raise the temperature of the air your AC has to cool.
The hotter the air your AC has to cool, generally the hotter the air your AC will circulate throughout your home. Your AC can only strip so much heat from your home’s air per cycle, and if really hot air is getting mixed in with the air circulating throughout your home, it can raise the temperature of air your AC cools.
If your supply ductwork has leaks in it, you will lose some of your conditioned air to unconditioned areas of your home. While this won’t change the temperature of the air your AC produces, the less cool air coming from your vents, the warmer your home may feel.
Duct leaks tend to increase your energy bills and increase the amount of dust around your home. If you notice any of these symptoms in conjunction with the fact that your air isn’t as cool as you’d like it to be, you probably have leaks in your ductwork.
The solution: Reach out to a professional for help. They will be able to check out your ductwork and repair or replace it as necessary.
Still having issues with your AC? Reach out to Four Seasons
If you’re still having issues with the temperature of your AC’s air, reach out to us for help. We’ve been helping Portland homeowners with their ACs since 1979, so we’ve seen it all. No matter what’s going on with your system, we’ll be here to accurately diagnose the issue and provide a reliable solution.
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