There is nothing more frustrating than hearing your AC unit humming away outside, feeling the air blowing through your vents, and still sweating inside your own home.
In Richmond TX, where summer temperatures regularly hit the mid to high 90s and the humidity makes it feel like you are breathing through a wet towel, an AC that runs but does not cool is not just uncomfortable. It is genuinely miserable. And it is costing you money every single hour it continues.
The good news is that most of the reasons an AC stops cooling properly are diagnosable and fixable. Some you can address yourself today. Others need a licensed technician with the right equipment. This guide walks through all nine so you know exactly what you are dealing with.
If you would rather skip the reading and just get it fixed, call Temper Mechanical at (346) 485-8142. We offer same-day AC repair in Richmond TX throughout Fort Bend County.
Before You Read Further: A Quick Reality Check
When your AC is running but not cooling, the instinct for most homeowners is to assume the worst. Compressor failure. Refrigerant gone. Full replacement needed.
In our experience working with hundreds of homeowners across Richmond, Sugar Land, Pecan Grove, and Rosenberg, that is rarely the case. More than half the time the issue is something far simpler. A dirty filter. A blocked condenser. A thermostat that needs recalibrating.
Work through this list in order. Start with the free and simple checks. You might find your answer in the first three minutes.
Reason 1: Your Refrigerant Is Low or Leaking
Refrigerant is the substance that actually removes heat from the air inside your home. When it is low, your AC blows air but cannot absorb heat the way it should. The result is air that feels slightly cool but never gets your home to the temperature you set.
Signs you have a refrigerant problem include air coming from vents that feels only mildly cool even after running for an hour, ice forming on the copper lines outside your unit or on the indoor coil, a hissing or bubbling sound near the unit, and your electricity bill going up without any explanation.
Here is what most homeowners do not know: refrigerant does not get used up. If it is low, there is a leak somewhere in the system. Simply adding more refrigerant without finding and fixing the leak is a temporary fix that will cost you again in 6 to 12 months.
A licensed technician can pressure test your system to find the exact location of the leak, repair it, and then recharge the refrigerant to the correct level.
Cost to expect: $200 to $1,500 depending on the severity of the leak and how much refrigerant needs to be added. The type of refrigerant your system uses also matters. Older systems using R-22 refrigerant are significantly more expensive to recharge because R-22 is being phased out globally.
Reason 2: Your Air Filter Is Completely Clogged
This is the most common cause of poor cooling that we find in Richmond TX homes and it is also the easiest to fix.
Your AC system pulls warm air from inside your home through the return vents and passes it over the evaporator coil to cool it before sending it back through your supply vents. The air filter sits in this path and catches dust, pollen, pet hair, and other particles before they reach the coil.
When that filter gets clogged, which in Fort Bend County’s humid environment happens faster than most homeowners expect, airflow through the system drops dramatically. Less air moving over the coil means less cooling happening per cycle. Your system runs longer, works harder, and still cannot get your home to temperature.
Go check your filter right now. Pull it out and hold it up to a light. If you cannot see light through it, replace it today. A new filter costs between $10 and $25 and takes two minutes to install.
In Fort Bend County we recommend checking your filter every 3 to 4 weeks during peak summer months. The combination of humidity, pollen, and how hard your system runs during Texas summers means filters fill up faster here than what the manufacturers typically account for.
Reason 3: Your Condenser Coils Are Dirty
Your outdoor AC unit contains the condenser coil, which is responsible for releasing the heat your system pulls from inside your home into the outdoor air. When this coil gets covered in dirt, grass clippings, cottonwood fluff, or debris, it cannot release heat efficiently.
The result is that heat gets trapped in the system. Your AC runs and runs but the refrigerant never fully releases its heat load before cycling back inside to try again. Cooling capacity drops noticeably.
You can see the condenser coil through the fins on the side of your outdoor unit. If it looks dark or matted with debris rather than clean silver metal, it needs cleaning.
Carefully rinsing the outside of the unit with a garden hose, directing water from the inside out, can help. But for a thorough cleaning of the coil fins, a professional with the right coil cleaning solution and low-pressure equipment will do the job properly without bending the delicate fins that make the coil work.
As a preventative measure, make sure nothing is growing too close to your outdoor unit. Keep at least two feet of clear space on all sides and at least five feet above. Richmond TX landscaping grows fast in the summer. What was two feet of clearance in April can be six inches by July.
Reason 4: Your Evaporator Coil Is Frozen
It might seem counterintuitive that an AC can get too cold, but it happens regularly.
The evaporator coil inside your air handler needs a constant flow of warm air passing over it to function correctly. When airflow is restricted, usually by a dirty filter or a failing blower motor, the coil gets too cold and moisture in the air freezes on its surface. Once ice starts forming, it acts as insulation and progressively reduces the system’s ability to cool your home at all.
Signs of a frozen evaporator coil include warm air coming from your vents despite the system running, water leaking around your indoor air handler, and visible ice on the copper refrigerant line going into the unit.
If you suspect a frozen coil, turn your thermostat from Cool to Fan Only. This keeps the blower running to push warm air over the coil and melt the ice without continuing to make it worse. Do not turn the system completely off. Give it 2 to 3 hours to fully thaw.
Once thawed, replace the air filter before turning cooling back on. If the coil freezes again, there is a deeper issue, either with airflow or refrigerant levels, that needs a technician to diagnose.
Reason 5: Your Thermostat Is Miscalibrated or Malfunctioning
Your thermostat is the brain of your entire cooling system. When it is not reading the temperature in your home accurately, it either tells your AC to stop too soon because it thinks the house is already cool enough, or it runs the system constantly because it never registers that the target temperature has been reached.
A thermostat that is off by even 3 to 4 degrees can make your home feel significantly warmer than the setting suggests. This is more common than most homeowners realize, particularly with older thermostats or with smart thermostats that have not been properly configured.
Check your thermostat by placing a separate thermometer next to it for 15 minutes with the AC off. Compare the reading. If they are more than 2 to 3 degrees apart, your thermostat needs recalibrating or replacing.
Also check where your thermostat is located. If it sits near a sunny window, above a lamp, near the kitchen, or close to an exterior door, it may be reading a higher temperature than the rest of your home and running your system more than it needs to. Location matters more than most people think.
Thermostat replacement is one of the most cost-effective upgrades you can make to your comfort and your energy bill. A properly calibrated smart thermostat can reduce your cooling costs by 10 to 15 percent annually.
Cost to expect: $150 to $300 installed for a quality smart thermostat.
Reason 6: Your Ductwork Is Leaking
Your air ducts are responsible for carrying the cooled air from your air handler to every room in your home. When those ducts develop cracks, separations at joints, or holes, a significant portion of that cooled air leaks out into your attic, walls, or crawl spaces before it ever reaches your living areas.
Studies from the Department of Energy suggest that the average American home loses 20 to 30 percent of its conditioned air through duct leaks. In older Richmond TX homes, that number can be even higher.
Signs of duct leakage include rooms that never seem to cool down no matter how long the AC runs, a noticeable difference in temperature between rooms on the same floor, higher than expected energy bills, and excessive dust in rooms that should be easy to keep clean.
Duct leakage is often invisible without a professional inspection because most ductwork runs through attics and wall cavities. A technician can perform a duct pressure test to measure how much air your system is losing before it reaches your living space.
Repairing duct leaks, depending on how extensive they are, can be one of the highest-return investments a Richmond TX homeowner makes in their home comfort. You are not buying more cooling capacity. You are simply making sure the cooling you are already paying for actually reaches you.
Reason 7: Your Compressor Is Struggling
The compressor is the heart of your AC system. It pressurizes the refrigerant and drives the entire cooling cycle. When it starts to fail, your system loses cooling capacity progressively. It still runs but with less and less effectiveness.
A struggling compressor often shows up as an AC that cools your home slightly but can never quite hit the set temperature, especially on hotter days. You might notice the system running almost continuously without achieving your desired indoor temperature.
Other signs include unusual sounds from the outdoor unit like grinding, clicking at startup, or a loud rattling, and the outdoor unit becoming noticeably hotter than normal during operation.
Compressor problems range from electrical issues that are relatively inexpensive to fix to full compressor failure, which is one of the most expensive AC repairs there is. A compressor replacement can cost $1,200 to $2,500 or more depending on the system size. At that price point we always give homeowners an honest comparison against the cost of a new system so you can make a fully informed decision.
This is not a DIY diagnosis. If you suspect a compressor issue, call a licensed HVAC technician who can properly test the electrical components and refrigerant pressures to determine exactly what is happening.
Reason 8: Your AC Is the Wrong Size for Your Home
This is one of the most overlooked causes of poor cooling and one of the hardest for homeowners to identify because the system appears to be working perfectly. It runs, it cools, but the house never quite gets comfortable.
An AC unit that is too small for the square footage it is trying to cool will run almost constantly without being able to keep up on hot Richmond TX afternoons. This is straightforward enough. But what surprises most homeowners is that an oversized unit causes just as many problems.
A unit that is too large for a home cools the space so quickly that it shuts off before it has had time to run long enough to remove the humidity from the air. In Fort Bend County where summer humidity regularly sits between 70 and 90 percent, this is a real problem. Your home might reach your set temperature but feel clammy and uncomfortable because the humidity has not been addressed. Mold risk also increases significantly in an improperly dehumidified home.
Proper AC sizing requires a Manual J load calculation that takes into account your home’s square footage, ceiling height, insulation levels, window size and orientation, how many people live in the home, and the specific climate conditions of your location. It is not just a square footage calculation.
If your AC was installed without this calculation being done, there is a real chance it is the wrong size. This is worth investigating if you have never been fully comfortable in your home despite having a functioning system.
Reason 9: Humidity Is Not Being Removed Properly
In most of the country, homeowners measure comfort primarily by temperature. In Richmond TX, humidity is just as important and sometimes more so.
A properly functioning AC system does two things simultaneously. It lowers the air temperature and it removes moisture from the air. The moisture removal happens as warm humid air passes over the cold evaporator coil, causing water vapor to condense on the coil surface and drain away.
When this dehumidification process is not working effectively, whether due to an oversized unit cycling too quickly, a refrigerant issue, or a problem with the drain line, your home can feel stuffy and uncomfortable even when the temperature reads exactly where you set it.
Signs that humidity is not being controlled include air that feels heavy or clammy inside, condensation on windows or walls, musty odors, and that feeling of never quite being comfortable no matter what temperature you set the thermostat to.
Solutions range from having your existing system checked and repaired to adding a whole-home dehumidifier that works alongside your AC to manage moisture levels independently. For Fort Bend County homes, a dedicated dehumidifier is often one of the single biggest upgrades for genuine comfort.
Our air duct cleaning services in Richmond TX can also help address air quality and moisture issues that accumulate inside your duct system over time.
What to Tell the Technician When You Call
Walking a technician through what you have already observed saves time and can reduce your diagnostic time significantly. Before you call, take note of these things:
How long has the problem been happening and did anything change around the time it started? How old is your AC system and when was it last serviced? What temperature is your thermostat set to and what is the actual temperature inside your home right now? Have you noticed any unusual sounds, smells, or visible ice anywhere on the system? Have you already replaced the filter?
The more specific you can be, the faster your technician can get you back to a comfortable home.
How Temper Mechanical Approaches This Differently
When you call most HVAC companies about an AC that is not cooling, the process goes like this. A technician arrives, does a quick visual check, tells you it is the refrigerant or the compressor, gives you a quote, and leaves it with you.
We do things differently and we are not just saying that.
Every diagnostic we do at Temper Mechanical includes a systematic check of every component in this list. We photograph what we find. We explain what each issue means in plain language. We give you the repair cost before touching anything. And we give you an honest recommendation, including when the answer is that your system is fine and a simple filter change was all it needed.
We have been doing this in Richmond TX and Fort Bend County long enough to know that trust is built one honest conversation at a time. Our 4.9 star rating from 165 Google reviews from your neighbors reflects that.
We serve homeowners throughout Fort Bend County including Sugar Land, Pecan Grove, Rosenberg, and Cinco Ranch.
When to Stop Troubleshooting and Just Call
If you have worked through the simple checks above and your AC is still not cooling your home properly, it is time to call a professional. Continuing to run a system with an underlying problem typically makes the issue worse and more expensive to fix.
Call us the same day if:
Your AC has been running for more than an hour and your home is more than 4 to 5 degrees warmer than your thermostat setting. You see ice anywhere on your system. You hear grinding, clicking, or banging from your outdoor unit. Your energy bill has increased significantly without any change in your usage. The air coming from your vents feels only slightly cool rather than cold.
Do not wait until the unit fails completely. Catching problems early almost always means a smaller repair bill.
Get Your Home Cooling Properly Again
Richmond TX summers are too long and too hot to spend them in a house that is not comfortable. Whatever is keeping your AC from doing its job, we can find it and fix it.
Call Temper Mechanical now: (346) 485-8142
Same-day service available throughout Richmond TX, Sugar Land, Rosenberg, Pecan Grove, and Fort Bend County. We answer 7 days a week.
Not ready to call? Fill in our quick form at tempermechanical.com/contact and we will call you back within 15 minutes.
Check our current AC repair specials before you call. We regularly run discounts for Fort Bend County homeowners.
Temper Mechanical Air and Heat LLC | 6115 FM 762 Rd Suite 1200, Richmond TX 77469 | (346) 485-8142