Why is my air conditioner running but not cooling the house?

Woman sitting in front of a fan.

Identifying Common AC Cooling Issues

Not only is it sunny in California, but it can get downright hot and humid too! This is why working air conditioners are important to businesses and homeowners. What a homeowner is often quick to learn is how important air conditioner refrigerant is to keep that cold air blowing. An AC without refrigerant isn’t going to do anything but blow warm air, and eventually, if you keep trying to use it, the unit will burn up. 

Before you panic and make that phone call for an AC technician, you can check your system yourself. Sometimes when an air conditioner stops cooling, it is something simple that doesn’t require any air conditioner refrigerant charging. How do you troubleshoot a home air conditioner?

The following are things you should check yourself before making that phone call that could end up costing you hundreds of dollars.

Check the Air Filter

A dirty air filter can cause several problems and left unaddressed, can actually lead to damaging the entire system. This should be getting changed every 30 days to keep the following from happening: 

  • Low airflow
  • Frozen refrigerant lines 
  • Frozen evaporator coil 
  • AC condensation overflowing the drip pan
  • Inadequate cooling, creating hot/cold spots and keeping AC from reaching the desired temperature setting
  • Energy bill increases
  • Total equipment failure

Replace the air filter whether it looks dirty or not.  Make a note to change the filter every 30 days regardless of whether it looks dirty. This is a good time to replace the batteries in your smoke alarm too.

Check the Thermostat Settings

This is the simplest of any possible DIY fixes. A thermostat on the wrong settings will cause the following: 

  • Only warm or hot blowing out of vents
  • Air conditioner not turning on

Check the thermostat switch is on “cool” and not heat. This problem is common at the first of summer when the weather is changing. Somebody may have accidentally switched it while dusting too, so it is always worth checking. 

Check the Circuit Breakers

This could be a simple fix when the circuit breaker flipped off that is keeping your AC from turning on. It could be a power surge in the area that caused it. If you flip it back on and it flips right back off, you need to call a professional AC technician or electrician. There could be something more serious with the electrical part of your HVAC system or it could be your system needs air conditioner refrigerant. This is something the technician can check and determine. 

Check the Outdoor Unit

An outdoor unit that is clogged with debris, grass, weeds, etc., or just simply dirty from outdoor exposure can cause the following: 

  • Energy bill increases
  • Warm air blowing from air vents
  • AC isn’t cooling adequately
  • Repairs needed too frequently

Check the outside unit of your air conditioning system. Rinse it off using the garden hose on a gentle spray. If you see dirt inside the unit covering the condenser, call your AC technician. Make sure any debris, grass, trash, and weeds aren’t sucked up against it. Keeping fences and foliage a minimum of 2 feet away from the outside unit is recommended. Check that  the air conditioner refrigerant line insulation is still intact as well.

Check All Air Vents

When the air vents are closed off or blocked, they can cause problems like: 

  • The AC has to struggle to cool 
  • Refrigerant lines freeze up
  • Evaporator coil freeze up
  • AC condensation overflows the drip pan
  • Damages compressor
  • Blower motor stops
  • Air ducts begin leaking, causing higher energy bills 

Walk through your home and open all air supply vents, even in empty rooms. Make sure drapes, furniture, or rugs are blocking the return vents. Homeowners often think that closing the vents in an unused room is an energy saving step, when in fact, it causes the AC system to work harder – and that reflects on the energy bill. 

How do I fix my AC if it’s not blowing cold air?

We just reviewed some common issues, many of which you can take care of yourself without calling a professional service technician. Let’s recap those things again that could help you get your AC blowing cold air: 

  • Power issues – make sure the unit is plugged in and the circuit breaker is flipped on. 
  • Thermostat issues – Make sure the thermostat is set “on” and “cold”. Replace the batteries. Remove the cover and blow any dust out with canned air or a hair dryer on “cool”. 
  • Clogged or Dirty Filter – Replace the AC filter. Some systems will automatically shut down when the filter is dirty so the motor doesn’t overheat.
  • Ice buildup – A dirty filter, frozen coils or refrigerant lines can cause ice to build up inside the unit. Replace the air filter and then run the system on “fan only” for a while and let it melt the ice off. If this doesn’t fix it, your system may need an air conditioner refrigerant charge and that will require a service call. 
  • Clogged condensation drain – As an air conditioner removes moisture from your home, that water drains through a hose and into a drain pan. The hose could be clogged, which will cause the system to shut down as a safety measure. Try to clean the hose out with a mild solution of bleach and water. 
  • Dirty compressor – The exterior portion of your AC system can get covered with dirt and dust, grass, trash, and weeds can get sucked up against it and cause the unit to shut down. Check around it and remove anything that could be blocking air flow. 
  • Low refrigerant levels – Refrigerant for ac units doesn’t evaporate or get bad. When an air conditioner refrigerant charge is needed, typically it is because of a leak somewhere within the system. The only solution for this is to call an AC technician. They have the equipment to check the air conditioner refrigerant and the authority to purchase more if needed. 

How do you know your AC needs refrigerant?

A few common indicators that your system needs air conditioner refrigerant: 

  1. Air conditioner constantly runs but the house isn’t cool. 
  2. Warm air blowing from the vents.
  3. Electric bills are higher than before.
  4. There is a buildup of ice on the refrigerant line.
  5. The refrigerant line has bubbles coming from and hissing sounds.

How do I find a leak in my AC?

This is something that should be done by a professional air conditioning technician. There are two ways you can check for a leak, with one being obvious – by looking for dirty, oily spots on the lines or around the unit. Refrigerant is an oily substance and if it is leaking, you’ll notice the oily marks. 

Another method is to mix dish soap with water and spray it on areas that you suspect are leaking. If there is air conditioner refrigerant leaking, it will blow soap bubbles there. Again, we must stress that the best way to find out if your system is leaking air conditioner refrigerant is to schedule a service call with a licensed professional contractor. 

Can I put refrigerant in my home AC?

Physically, with the proper equipment and tools anyone with a mechanical sense can install their own air conditioner refrigerant. However, legally, you cannot purchase the refrigerant needed. The EPA has established laws that prevent everyday citizens from purchasing air conditioner refrigerant. Only certified and licensed contractors are permitted to purchase the product. 

Woman relaxing underneath an air conditioner vent.

In Conclusion 

You may wonder why you can’t do your own air conditioning install or charge your own air conditioner refrigerant. Is air conditioner refrigerant harmful? Yes, the substance that is used as air conditioner refrigerant is a tasteless, semi-odorless gas. When this gas is deeply inhaled, it cuts off the oxygen to the brain and lungs. This is why the EPA has established strict laws to who can purchase and use this gas. In the wrong hands with lack of knowledge, it can be deadly. If you find yourself in need of help refilling or replacing your air conditioner refrigerant, you can reach out to the A 100% Guarantee Heating and AC team by calling 707-689-5128.