Air Conditioning Is Not Cooling? Here's What Might Be Wrong

Tips to Inspect your AC Unit when It's Not Cooling

There’s nothing worse than walking into your home on a sweltering summer day, flipping on the AC, and realizing… it’s not doing its job. If your air conditioning is not cooling your home, it can feel like you’re left sweating with no clear solution. At Climate Works Heating, Cooling & Plumbing, we’ve helped thousands of homeowners across Ottawa troubleshoot their AC issues. This guide walks through the most common reasons your AC might be running—but not cooling—and what you can do about it.

Start with the Thermostat

It might sound obvious, but sometimes the fix starts with the thermostat. Maybe it’s set to “heat” instead of “cool.” Maybe the batteries are dead, or it just needs a hard reset. We’ve even seen cases where the thermostat was installed in direct sunlight, tricking the system into thinking your home is warmer than it is.

If everything looks correct and the unit still isn’t responding properly, the thermostat itself could be faulty. That’s when it’s time to bring in a technician to check the wiring or recommend a replacement.

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Low on Refrigerant? It Happens More Often Than You Think

If your system is blowing warm air even though it’s running, you might be dealing with a refrigerant issue. This chemical is essential for pulling heat out of your home—and if it’s low or leaking, cooling just won’t happen.

Homeowners often notice ice building up on the refrigerant lines or hear a quiet hissing sound. That’s usually a sign of a leak, which needs professional attention right away. Not only does it affect your comfort, but refrigerant leaks can damage your compressor and increase your energy use.

Dirty or Frozen Coils Can Kill the Cool

Another common reason your air conditioning is not cooling is frozen or dirty coils. Inside your system are evaporator and condenser coils that absorb and release heat. If they’re caked in grime or ice, they can’t do their job—and your house stays hot.

This kind of buildup is often caused by clogged filters, airflow issues, or old refrigerant problems. It’s something our team can clean up during a routine tune-up, but left too long, it can lead to system damage.

The Outdoor Unit Needs Breathing Room

Your AC’s condenser unit sits outside and releases the heat pulled from your home. But if it’s covered in leaves, weeds, or dirt, it struggles to function properly.

We recommend keeping the area around the unit clear—think of it like giving your AC room to breathe. You’d be surprised how often we find systems totally smothered by overgrown shrubs or mulch. 

When It Just Won't Turn On

If your air conditioner won’t turn on at all, there are a few likely culprits. A tripped circuit breaker, a full drain pan, or a disconnected condenser wire could all be to blame.

Sometimes it’s something as small as a blown capacitor, or as serious as a failed compressor. If the usual checks don’t solve it, it’s time to call in the pros. At Climate Works, we’re available 24/7 for emergencies, so you’re never stuck without help on a hot day.

Maybe Your System Just Can't Keep Up

Sometimes, your air conditioning is not cooling simply because it’s the wrong size for your home—or it’s nearing the end of its lifespan. If your system is more than 15 years old, or if you’ve recently renovated and added space, it might not be powerful enough to do the job anymore.

We can run a full system evaluation and recommend a right-sized solution that’ll actually keep you cool—without running nonstop. 

Keep It From Happening Again

A lot of AC issues can be prevented with regular maintenance. That means more than just changing filters—it means giving your system a professional tune-up each spring before the hot weather hits.

At Climate Works, we offer comprehensive maintenance plans that catch problems before they become emergencies. According to Natural Resources Canada, regular tune-ups and proper sizing can keep your air conditioning system running efficiently for years.

Frequently Asked Questions (FAQ)

If your air conditioning is not cooling and you’re still unsure what’s going on, these quick FAQs might help clear things up. From filter issues to frozen coils, we answer the most common questions Ottawa homeowners ask when their AC just isn’t keeping up.

Cooling FAQ for Ottawa Homeowners

How often should I change my air filter?

Ideally every 1–3 months. If you have pets or allergies, monthly changes are best.

Is it dangerous to run an AC with a refrigerant leak?

It's not just bad for your AC—leaks can be hazardous and should be addressed by a certified technician.

Why is my AC running but not blowing cold air?

Could be a clogged filter, frozen coil, low refrigerant, or thermostat issue. Start with simple checks, then call us if needed.

Can I fix a frozen coil myself?

You can turn off the system and let it thaw, but it's important to fix the underlying issue with professional help.

How do I know if it's time to replace my air conditioner?

If it's over 15 years old, breaking down often, or not keeping your home cool despite repairs—it's probably time.

What should homeowners know about tips to Inspect your AC Unit when It's Not Cooling?

There’s nothing worse than walking into your home on a sweltering summer day, flipping on the AC, and realizing… it’s not doing its job. If your air conditioning is not cooling your home, it can feel like you’re left sweating with no clear solution. At Climate Works Heating, Cooling & Plumbing, we’ve helped thousands of homeowners across Ottawa troubleshoot their AC issues. This guide walks through the most common reasons your AC might be running—but not cooling—and what you can do about it.

Need Fast Help with an AC That's Not Cooling?

If your air conditioning is acting up and your home just won’t stay cool, don’t sweat it—Climate Works is here to help. With locations in Ottawa and the National Capital Region, our expert technicians are ready to diagnose and fix the issue fast. Call us today or schedule a visit and get your comfort back on track.

Contact Us

Ottawa (Headquarters)

2639 Pollock Rd.
Richmond, ON, K0A 2Z0
info@climateworks.ca | 613-838-9989