We all know numbers matter. A few degrees can make the difference between feeling just fine and sweating through your t-shirt in your own living room. When your thermostat won’t drop below 75 degrees, it doesn’t just feel warm — it feels like a serious problem. Especially when you’ve got little ones trying to nap, or you’ve just finished mowing the lawn and were counting on a cool blast of air to greet you at the door.
Are you standing with your hands on your hips, asking, “Why is my AC not cooling below 75 degrees?” You’re in the right place. Let’s walk through some of the most common reasons your system might be struggling and how you can fix them.
Understanding What’s Normal — and What’s Not
Most folks expect their air conditioning to keep things at a comfortable 70 or even lower during the peak of summer. If your AC is not cooling below 75 degrees, that’s a signal that something isn’t quite right. It could be a maintenance issue, a mechanical problem, or even something as simple as a blocked vent or dirty filter. Before jumping into fixes, it’s good to get a feel for what could be causing your cooling issues.
Airflow Problems That Limit Cooling Power
Without good airflow, your air conditioner can’t do its job properly. Let’s start with a few issues that block or restrict air movement in your home.
Dirty or Clogged Air Filter
One of the most likely reasons why your AC unit is not going lower than 75 is right in your return vent. A dirty air filter blocks the flow of air and keeps cool air from circulating through your home. This forces your system to work harder while delivering less comfort.
Blocked or Closed Vents
Sometimes it’s the simple things. If furniture is covering vents or if someone closed a few off, thinking it would help cool other rooms, it can throw off the whole system. Make sure every supply and return vent is open and clear.
Trouble at the Thermostat
Your thermostat tells your AC when to turn on and off, so it plays a considerable part in how cool your home gets. A malfunctioning thermostat could be a big reason why your air conditioner won’t cool below 75 degrees.
Inaccurate Temperature Readings
If the thermostat is in direct sunlight, near a hot appliance, or placed too high on the wall, it may think the room is cooler than it really is. That can cause it to shut off early, keeping things warmer than you want.
Old or Failing Thermostats
Old thermostats can lose their accuracy, or they might not be compatible with your current heating and cooling setup. Upgrading to a smart thermostat can help manage energy use and temperature more efficiently.
Low Refrigerant and Leaks
If your AC is blowing air but not cooling properly, you might be dealing with a refrigerant issue. This is one of the more technical reasons why your AC unit is not going lower than 75.
Signs of a Refrigerant Leak
Ice buildup on the evaporator coil, warm air coming from vents, or a hissing sound near the outdoor unit are all warning signs of a refrigerant leak. It’s important to know that a leak means your system can’t transfer heat properly, so it’ll struggle to cool your space.
Why It Matters
Without enough refrigerant, your AC system loses its cooling punch. Even if every other part is running fine, low refrigerant pressure can keep the temperature stuck, no matter how long it runs.
Do you think you have a refrigerant leak? Ease your mind by calling Busy Bee Plumbing, Heating & Air Conditioning. We offer air conditioner repair in Nashville, TN, and the surrounding areas. We’ll get to the bottom of why your air conditioner won’t cool below 75 degrees and restore your family’s comfort.
Outdoor Unit Problems
The outdoor condenser unit is where a lot of the heavy lifting happens in your air conditioning system. If it’s struggling, that could be why your AC unit is not going lower than 75.
Dirty or Blocked Condenser Coils
Your AC releases heat outdoors through the condenser coils. When those coils get covered in dirt or leaves, that heat doesn’t go anywhere, and your home doesn’t cool off. This forces the system to work harder while barely making a dent in the temperature.
Compressor or Capacitor Issues
The compressor is the engine behind your system’s cooling. If it’s wearing out or if the capacitor isn’t sending the right voltage, your AC might not have the power to cool below 75 degrees. If you hear buzzing, humming, or clicking, it may be time to call a technician.
Poor Ductwork and Insulation
Air might be getting cooled just fine, but if it’s leaking out of your ducts or warming up before it gets to your living space, this could be why your air conditioner won’t cool below 75 degrees.
Leaky or Uninsulated Ducts
Attics, basements, or crawl spaces can cause major energy losses if your ductwork isn’t sealed or insulated properly. That cool air gets lost in the shuffle, and you’re left wondering why it’s still warm inside.
Crushed or Disconnected Ducts
Sometimes ducts get kinked or pulled apart, especially in older homes or after attic work. Even a small disconnect can make a big difference in airflow and cooling performance.
Heat Load and House Design Factors
There are times when your AC isn’t broken — it’s just outmatched. If your home has poor insulation, large windows, or lots of open space, it might struggle on hotter days.
Attics and Basements
Attics without good ventilation act like ovens in the summer. Heat seeps into the ceiling and warms everything below. Basements without proper drainage or airflow can also hold moisture and humidity that raise the temperature inside.
Large Glass Windows and Sunlight
Sun pouring through untreated windows during a Tennessee summer? That’s a recipe for warm rooms and an overworked air conditioner. Adding blinds, shades, or reflective film can help manage indoor temperatures.
Humidity Can Be a Hidden Culprit
Even if your thermostat shows 75, high humidity can make it feel more like 80. Your AC removes moisture along with heat, but if it’s not doing that well, the air will still feel heavy and uncomfortable.
Consider a Dehumidifier
Adding a whole-home dehumidifier or a standalone unit in problem areas can take a load off your AC. Less moisture means more comfort, even if the number on the thermostat doesn’t change much.
When to Consider an Upgrade
If you’ve checked the filters, cleaned the coils, and still can’t figure out why your AC is not cooling below 75 degrees, it might be time to think about replacing your unit.
Older Systems Struggle in the Heat
Air conditioners over 12–15 years old often lose efficiency, especially during Tennessee’s peak heat. Upgrading to a newer model with better energy efficiency can improve performance and lower your energy bills.
Need help choosing the right system? Turn to Busy Bee Plumbing, Heating & Air Conditioning. Our trusted central AC installers can help you review your options and determine what works best for your home.
Call Busy Bee and Cool Down Today!
At the end of the day, your family deserves to come home to a space that feels cool, calm, and comfortable. If you’re tired of wondering why your AC unit is not going lower than 75, give Busy Bee Plumbing, Heating & Air Conditioning a call at 615‑991‑2145.
We’ve been helping homeowners beat the heat since 1997. With honest service, reliable repairs, and a 100% satisfaction guarantee, we treat your home the same way we’d treat our own. Our team goes through regular training, so we’re always ready to help you make the right call for your comfort.
Let us help you solve why your AC is not cooling below 75 degrees and get your house back to feeling just right. Contact us today to schedule your service!
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