If you can tell your air conditioner is on, you have every right to expect to feel the cool air it should be providing. But what if you don’t? You might need AC repair. Several issues can cause an air conditioner to make noises as though it’s running properly without actually cooling your home. We’ll explain the possibilities.
Why is my AC running but not cooling my house?
If your AC is running but not cooling, several common HVAC issues may be the cause:
- Dirty air filter: A clogged filter restricts airflow and reduces cooling performance.
- Blocked condenser unit: Dirt or debris on the outdoor unit can stop it from releasing heat properly.
- Frozen evaporator coils: Often caused by low refrigerant or poor airflow, freezing reduces cooling ability.
- Leaky ductwork: Holes or gaps in ducts allow cool air to escape before reaching your rooms.
Low refrigerant levels: Leaks or undercharging prevent the system from cooling effectively.
Your Air Filter Is Clogged
This is a best-case scenario, in which you don’t need AC repair at all. Simply check your air filter. If it’s caked with a thick blanket of dust and particles, swap it out for a new one, or wash and dry your filter if it’s reusable. Does this do the trick? Do you have plenty of cool air coming out of your vents now? Fantastic! Make sure to replace your air filter monthly.
Your Outdoor Unit Is Dirty
The heat the refrigerant carries from your home needs to dissipate while the refrigerant flows through the outdoor unit, so it will be cold enough to soak up more heat when it gets back inside. Dirt, lawn clippings, last fall’s leaves, or encroaching plants can insulate the coils so the heat is not able to dissipate. Rake and trim everything away, and wash down the unit, using only gentle hose pressure.
Your Indoor Unit Is Icy
A buildup of ice might seem cold, but just like the mess on the outdoor unit, ice on the indoor unit can actually act as insulation. In this case, it’s preventing the refrigerant from absorbing the heat while it’s inside your home. This ice can develop because of a fan or motor problem or a refrigerant leak, which will require repair, or because of a clogged air filter, which you can check yourself.
Your Ductwork Is Leaky
Even if the air conditioner is generating plenty of cold air, it could still fail to make it out of your vents. Damage or deterioration can cause your ductwork to leak, allowing your cooled air to seep out into places where it’s not needed, like in your attic. Minor damage can easily be repaired by a qualified HVAC technician, while widespread leaks might necessitate duct replacement. If your system still isn’t cooling properly, here’s what to do if AC fails in heatwave.
Your Refrigerant Is Low
An air conditioner doesn’t use up refrigerant. It simply cycles it through a closed loop. But if a coil is damaged, refrigerant may leak out, causing the system to be unable to cool effectively. Other indicators are hissing or bubbling sounds, a sweet chemical smell, or the ice mentioned above. The coil can be sealed by a technician and the refrigerant can be topped back up.
If you notice your AC running but not cooling in Lansing, MI, check on the air filter and outdoor unit first. If cleaning those doesn’t resolve your problem, one of these other issues is likely to be the root cause. Get qualified help right away to prevent sky-high electric bills or further damage to your AC system.
Frequently Asked Questions
Question: What are the most common reasons an air conditioner runs but does not cool the house?
Answer: The usual culprits include dirty or clogged air filters restricting airflow, incorrect thermostat settings, low refrigerant levels, dirty condenser coils, frozen evaporator coils, ductwork leaks, or failing compressor or fan motors. In some cases, the unit may be too small or nearing the end of its lifespan.
Question: What simple checks can I do myself before calling a technician?
Answer: You can verify the thermostat is set to “cool” and below room temperature, replace or clean the air filter, ensure vents are open, clear debris around the outdoor condenser, check the circuit breaker, and let the system thaw if ice is present on the coils or lines.
Question: How can I tell if low refrigerant is the problem?
Answer: Signs of low refrigerant include weak airflow, reduced cooling, ice on the coils or lines, strange hissing or bubbling sounds, and higher energy bills. Diagnosing or refilling refrigerant should always be done by a licensed HVAC technician.
Question: What causes evaporator coils to freeze and why does that stop cooling?
Answer: Frozen evaporator coils are often caused by restricted airflow from dirty filters or low refrigerant levels. When coils freeze, they can’t absorb heat properly, preventing the system from cooling your home. Thawing the unit and addressing the root cause usually resolves the issue.
Question: When is it time to call an HVAC professional?
Answer: Call a professional if DIY checks don’t restore cooling, you see ice on coils frequently, hear unusual noises, suspect a refrigerant leak, or if the unit is old or showing signs of failure. Professional help is essential for electrical, refrigerant, or mechanical repairs.
Contact A-1 Mechanical Heating & Cooling for AC repair in Lansing, MI. Comfort and Character You Can Depend On.