Why is my AC not cooling?
- CMCPHC
- Jul 24
- 2 min read
If your air conditioner isn't cooling your house — especially during a heat wave — you're not alone. This is one of the most common HVAC issues we hear about every summer. Whether your system is running non-stop or blowing warm air, here are a few things you can check before calling for service.
1. CHECK YOUR THERMOSTAT SETTINGS
Make sure your thermostat is set to "cool" and the fan is set to "auto", not "on." A fan that's always running may circulate warm air even when the AC isn’t actively cooling.
2. CHANGE YOUR AIR FILTER
A dirty or clogged filter can severely restrict airflow and make your AC feel useless. Replace your air filter if it looks dusty, clogged, or hasn’t been changed in 1-3 months.
3. INSPECT YOUR BREAKERS
Sometimes, the outdoor condenser unit trips the breaker, especially during long stretches of extreme heat. Check your electrical panel and reset any tripped breakers — but if it keeps happening, that’s a sign to call a pro.
4. LOOK AT THE OUTDOOR UNIT
Head outside and check your condenser unit. If it's covered in cottonwood, leaves, or debris, your system could be suffocating. Gently rinse it off with a hose (with the power off) to help it breathe.
5. CHECK FOR ICE ON THE LINES
If you see ice forming on your copper lines, shut the system off and let it thaw. Ice buildup could mean restricted airflow or a refrigerant issue — both of which need professional attention.
6. DON’T DROP THE THERMOSTAT TOO LOW
During a heat wave, your AC might struggle to keep up. It’s normal to see temps inside 7–10 degrees above your set point when it’s 90–100+ degrees outside. Setting your thermostat to 68° won't make it cool faster — it'll just run harder.
WHEN TO CALL A PRO
If you’ve tried these troubleshooting tips and your AC still isn't cooling, it’s time to bring in an expert. At CMC Plumbing, Heating & Cooling, we help homeowners across Madison Heights and Metro Detroit stay cool and comfortable — even during record-breaking heat.
✅ Fast, friendly service
✅ Straightforward pricing
✅ Ask about our Fahrenheit & Flow Service Plan – it includes seasonal tune-ups and exclusive discounts to help prevent problems like this in the first place.
Based in Madison Heights | Serving Metro Detroit
📞 248-546-8800 | 📧 service@cmcphc.com
Disclaimer: The information provided in this blog is for general educational and informational purposes only. Every home and system is different, and not all advice may apply to your specific situation. For personalized recommendations, code-compliant work, or professional service, please contact CMC Plumbing, Heating & Cooling. We’re licensed, experienced, and happy to help you get the job done right.
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