AC Running But Not Cooling House?

The summer sun is beating down on your roof. You walk into your living room and expect to feel a nice cold breeze. Instead, the air feels hot and sticky. You can hear your heavy machine working hard outside. If you find your AC running but not cooling house rooms perfectly, you are wasting a lot of money on electrical power. Your machine is trying to push the hot air outside but something is blocking the path. We will help you find the broken parts and make your home totally comfortable again.

The Dirty Filter Problem

Blocked Cold Air

Your machine needs to breathe air from your house. It pulls the warm room air through a paper filter. This cheap cardboard filter traps thick dog hair and grey dust. Many people forget to change this paper square. A completely dirty filter chokes the heavy cooling machine. The cold air cannot pass through the thick wall of dirt to reach your bedroom.

Freezing Metal Parts

When the air gets trapped, the cold metal pipes inside your machine get way too cold. They turn into a giant block of solid white ice. A frozen machine will only blow warm air. You can read our AC Blowing Warm Air But Outside Unit Running guide to learn how this thick ice destroys your expensive motors.

DIY Maintenance Tip

The Light Bulb Test

You can easily check your paper air filter right now. Pull the dirty cardboard square out of the metal slot in your basement. Hold the filter up to a bright ceiling light bulb. If you cannot see the bright light shining through the paper, the filter is completely dead. You must throw it in the trash and push a brand new white filter into the slot. You can use our HVAC Calculators to figure out the exact size of your cooling system to buy the right parts.

The Outdoor Metal Box

Clogged Metal Fins

Look at the large metal box sitting in your backyard. This box pushes all the heat from your house into the outside sky. The metal walls are made of tiny silver fins. These tiny fins get clogged with thick green grass, dead leaves, and sticky dirt. The hot air gets trapped inside the metal cage if the fins are dirty. Use a gentle water hose to wash the green grass off the metal walls. Check the Energy.gov Central Air Conditioning page to see why keeping this box clean saves you money.

Broken Fan Motors

A large metal fan blade sits on top of the outdoor box. This heavy fan must spin very fast to cool the machine. Sometimes the small electrical starting piece breaks. This piece is called a capacitor. The heavy fan will just hum loudly and get very hot. The machine will blow warm air because the fan cannot spin to push the heat away.

Average Repair Costs

System Component	Main Purpose	Expected Lifespan	Estimated Part Cost	Estimated Labor Cost
Paper Air Filter	Cleans the indoor air	1 month	$10 to $20	Free to do yourself
Silver Capacitor	Starts the heavy fan	5-10 years	$20 to $40	$150 to $250
Outdoor Fan Motor	Blows hot air outside	10-15 years	$150 to $300	$300 to $500
Chemical Freon	Makes the pipes cold	10-15 years	$50 to $100	$300 to $600
Main Compressor	Pumps the cold liquid	10-15 years	$800 to $1500	$1500 to $2500

Missing Cold Chemicals

The Chemical Loop

Your machine uses a special chemical liquid to make the copper pipes freezing cold. This magic liquid travels in a giant circle. The system never drinks this liquid. It just moves it around forever. Sometimes a tiny hole opens up in the old copper pipes.

Finding Tiny Leaks

The expensive chemical leaks out into the sky. Your machine will run all day but the air will never get cold because the magic liquid is gone. A professional worker uses a special electronic sniffing tool to find the invisible hole. They weld the tiny hole shut and put fresh liquid back inside. Read our AC Refrigerant Leak Repair page to learn about this delicate plumbing process.

When To Call A Pro

Broken Electrical Parts

Your wall thermostat tells the outdoor machine when to turn on. The outdoor machine has a black plastic switch that acts like a heavy bridge for the electrical power. Bugs and ants love to hide inside this warm plastic switch. A crushed bug will block the electrical power completely. The main pump will never turn on. Read the EPA Refrigerant Regulations page to see why only certified professionals can handle these complex repairs safely.

Is your house feeling like a hot oven right now? Does your outdoor machine make a loud humming sound but the fan refuses to spin? Our expert cooling team can test your heavy motors today. We carry brand new silver capacitors and clean chemicals in our work trucks. We will fix your broken parts and make your family comfortable again.

FAQ

Why is my AC running but not cooling house rooms evenly?

Your machine is struggling to push cold air evenly because a dirty paper filter is blocking the airflow or the outdoor metal fins are covered in thick dirt and dead grass.

Can a broken outdoor fan stop my house from getting cold?

Yes, if the large fan blade stops spinning, the hot air gets trapped inside the metal box and the main computer shuts the cooling process down.

Should I turn the machine completely off if it blows warm air?

You must turn the machine off at the wall thermostat immediately to stop the expensive motors from burning up while they try to work without cold chemicals.

How much does it cost to fix a broken cooling machine?

A professional cooling worker will usually charge between $150 and $250 to find the exact broken electrical part in your yard and replace it safely.

Why is there solid white ice on my copper pipes in the summer?

Solid ice forms when a totally clogged air filter traps the freezing cold air inside the dark metal box instead of pushing it into your warm rooms.

Conclusion

A hot house is very stressful for your family. You must check the simple things first. Pull your paper air filter out and see if it is covered in thick grey dust. Walk outside and gently wash the dead grass off your outdoor metal box. Listen for a loud humming noise coming from the heavy fan motor. A professional worker can safely add fresh cooling chemicals for about $300. Open our HVAC Services page to get safe cooling help right away.