It’s the beginning of a Columbia summer, your AC unit is humming along outside, the air handler is blowing, but your house just won’t cool down. What gives?
This is one of the most common calls we get at Stoudenmire Heating & Air, because “running” doesn’t always mean “working correctly.” There’s a big difference between a system that’s powered on and a system that’s actually cooling the air the way it should be.
Here are the most common reasons your AC feels weak and what to do about each one.
This is the first thing we check, and it causes more cooling problems than most homeowners realize. A dirty filter restricts airflow so badly that even a perfectly functioning system can’t push enough conditioned air through your home.
Signs this is your problem:
• Weak airflow from vents
• The air coming out feels cool, but there’s barely any of it
• You can’t remember the last time you changed the filter
What to do: Check and replace your filter. In South Carolina summers, most homes should change filters every 30–90 days. If you have pets or allergies, even more frequently.
It sounds backwards, but your indoor coil can literally freeze up in the middle of summer. This usually happens when airflow is restricted or when refrigerant levels are low. Ice blocks the coil from absorbing heat, so your system keeps running but nothing gets cooler.
Signs this is your problem:
• Warm air blowing from vents despite the system running
• Ice visible on the refrigerant lines going into the air handler
• Water pooling around the indoor unit
What to do: Turn the system off and let it thaw (switch to “fan only” mode to speed this up). If it freezes again, that’s a sign of a deeper issue and it’s time to call a technician.
Refrigerant (freon) is what removes heat from your home’s air. If your system has a leak and refrigerant levels drop, your AC will run constantly but struggle to cool. Contrary to popular belief, refrigerant doesn’t “run out” like gasoline; if it’s low, that means there’s a leak somewhere that needs to be found and repaired.
Signs this is your problem:
• AC runs for a long time but never quite reaches your set temperature
• Higher-than-normal electric bills
• Hissing or bubbling sound near the unit
What to do: This one requires a licensed HVAC technician. Adding refrigerant without fixing the leak is against EPA regulations & does not solve the root issue. The right fix involves finding the leak, repairing it, and properly recharging the system.
The outdoor unit (condenser) dumps the heat your system pulls from inside your house. If it’s caked with dirt, grass clippings, or blocked by overgrown plants, it can’t do its job, and your whole system suffers.
Signs this is your problem:
• You can visibly see debris on the fins of the outdoor unit
• The area around the unit is overgrown
What to do: Keep at least 2 feet of clearance around the condenser. Gently rinse the fins with a garden hose (spray from the inside out). For a deeper coil cleaning, schedule a professional tune-up.
Columbia summers are no joke, we regularly see heat index above 105°F. If your system was undersized when installed (or you’ve added square footage, more windows, or have had insulation changes), it may just be outmatched on the hottest days.
Signs this is your problem:
• The system runs almost constantly without shutting off
• Certain rooms are always warmer than others
• The problem only shows up on the hottest days
What to do: A Manual J load calculation can determine the right size system for your home. If you’re due for a replacement anyway, this is the time to get it right.
Up to 30% of cooled air can be lost through leaky ducts before it ever reaches your living space. That’s conditioned air you’re paying to cool that ends up in your attic or crawlspace instead of your living room.
Signs this is your problem:
• Uneven cooling from room to room
• High energy bills that don’t match how much the system runs
• Some vents have noticeably less airflow than others
What to do: Duct sealing and duct testing can identify and fix these leaks. It’s one of the best investments you can make in your system’s efficiency.
Some of these issues you can address yourself, but if you’ve checked the basics and your AC still isn’t keeping up, it’s time to have a technician take a look before a manageable problem turns into a full system failure in the middle of July.
Call us sooner rather than later if:
• Your system is blowing warm air
• You suspect a refrigerant leak
• The indoor or outdoor unit is icing over
• Your system runs constantly but can’t hit your set temperature
Stoudenmire Heating & Air has been keeping Columbia homes comfortable for decades. If your AC is running but not cooling, our technicians can diagnose the problem fast and fix it right.
Serving Columbia, Lexington, Irmo, Chapin, West Columbia, and the surrounding Midlands.