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Air Conditioning

Why is My AC Not Blowing Cold Air?

Are you wondering, “Why is my air conditioner not blowing cold air?” If so, you’re not alone. Whether it’s a central system that’s gone silent or a ductless split that’s acting up, an AC not blowing cold air is one of the most common summer service calls we get at Comfort Zone.

In this guide, we’ll walk you through the possible reasons for this issue, how to fix it, and when to call in the professionals.

9 Possible Reasons Your Home AC Is Not Blowing Cold Air

  1. Clogged Air Filters
    One of the simplest reasons your AC is not blowing cold air is a dirty or clogged air filter. When the filter is packed with dust, pet hair, or pollen, it restricts air flow and makes your unit work harder. This can even cause the motor to overheat and shut down in extreme cases.
  2. Low Refrigerant Levels
    Air conditioners rely on refrigerant to cool the air before it’s circulated throughout your home. If your AC is working but not blowing cold air, it could be because the refrigerant levels are low (probably due to a leak).Warning Signs:

    • Ice buildup on the outdoor unit or refrigerant lines
    • Hissing sounds
    • Your AC runs constantly but doesn’t cool the house
  3. Power Problems
    Air conditioners draw a lot of power at startup. If your AC isn’t turning on at all, it could be due to:

    • A tripped breaker or blown fuse
    • A disconnected or damaged power cord
    • A motor overload switch that needs to be reset
  4. Frozen Evaporator Coil
    Issues like low refrigerant or a dirty filter that’s hampering air flow can cause your AC unit to go into overdrive, leading to a frozen evaporator coil. A frozen coil prevents your AC from absorbing heat, meaning no cold air gets into your home.
  5. Thermostat Troubles
    Sometimes the issue isn’t with your AC unit at all; it’s the thermostat. If your system isn’t turning on or the room never seems to cool, double-check that your thermostat is correctly calibrated and working properly.
  6. Dirty, Damaged, or Blocked Compressor Coils
    Your outdoor AC compressor releases heat from your home. If the unit is covered in dirt, leaves, or debris, or if the coils are damaged, your AC will struggle to release heat and cool your home efficiently.
  7. Blower Motor or Fan Problems
    If your central AC is not blowing cold air, listen for the sound of the indoor blower fan. If it’s weak or silent, you may have an issue with your blower motor or fan.You might also notice:

    • Airflow seems weak from the vents
    • The unit runs but doesn’t cool
    • Strange rattling or grinding noises
  8. Drain Clog
    Your central AC removes moisture from your home as it blows cold air. That moisture collects in a drainpipe, which, over time, can get clogged with algae, debris, or mold.Thankfully, it’s a simple fix. An HVAC technician can quickly and easily clear clogged AC drain lines.
  9. Duct or Airflow Issues
    For homes with central AC, the issue can also be due to leaky ductwork, blocked vents, or poor circulation. This is especially true if:

    • Some rooms are cooler than others
    • You notice little or no airflow from certain vents
    • Your utility bills have spiked

How to Fix an AC Not Blowing Cold Air

  1. Check and Replace Air Filters
    Start here. Filters should be replaced every 1-3 months, especially during high-use seasons. A clean filter improves airflow and system performance.
  2. Inspect the Thermostat
    Make sure:

    • It’s set to “Cool” mode
    • It’s set to a lower temperature than the room
    • The batteries are working

    If you still suspect an issue, our techs can test or replace your thermostat.

  3. Clear Debris from the Outdoor Unit
    Gently remove dust, dirt, and leaves from the compressor coils. Keep bushes and grass trimmed back at least 2 feet from the unit.
  4. Melt Ice on Frozen Coils
    Turn the system off but keep the fan running to help melt any ice buildup. If it keeps freezing, it’s time for a professional evaluation.
  5. Look for Blocked Vents or Duct Issues
    Ensure vents aren’t blocked by furniture, curtains, or rugs. If certain rooms still don’t cool, leaky ducts may be the issue.
  6. Check for Refrigerant Leaks (Leave this to the pros)
    If you see ice, hear hissing, or suspect low refrigerant, don’t try to fix this yourself. Only certified technicians can safely handle refrigerants. Book an appointment for AC repair near you.
  7. Schedule a Professional Inspection
    If your heat pump or central AC is not blowing cold air and you’ve ruled out simple issues, Comfort Zone Services can help. We’ll diagnose the problem and provide repair or replacement options. If you do need a new AC unit, we’ll help you decide on the best choice for your home and budget.

Not Sure What’s Causing It?

If your AC is working but not blowing cold air, don’t suffer through the heat. Whether it’s a quick fix or a more complex repair, Comfort Zone Services is here to help. We offer:

  • 24/7 emergency AC repair in London, Ontario
  • Repairs and maintenance for all makes and models
  • Transparent quotes with no pressure
  • Friendly, experienced HVAC technicians

We’re proud to be one of the top-rated names in AC repair London homeowners trust.

Still Wondering, “Why Is My AC Not Blowing Cold Air?”

Let’s find out together. Schedule an appointment with one of our licensed air conditioning contractors, and we’ll get your home cool and comfortable again — fast.

Call us today for expert air conditioner repair in London, Ontario.