Cooling Emergency
Electric Bill Shot Up?
If your bill jumped and nothing else changed, your HVAC system is the prime suspect. Here's what to investigate.
What's Going On
Understanding the Problem
Your electricity bill is significantly higher than the same month last year (or higher than what you'd expect), and you haven't added new appliances or changed your habits. In Houston, HVAC accounts for 50–70% of your electric bill in summer. Even a small drop in system efficiency can add $50–200/month to your bill.
Diagnosis
Common Causes
1Dirty air filter or coils
A clogged filter or dirty coils force the system to run longer and harder to reach the set temperature. It might get there eventually, but it's using far more electricity to do it.
2Refrigerant leak
A slow refrigerant leak reduces cooling capacity. The system runs longer cycles trying to cool the house, consuming more electricity without achieving the right temperature.
3Aging or failing system
As AC systems age (especially past 12–15 years), they lose efficiency. A system rated at 14 SEER when new might be operating at 8–10 SEER now, using 40–50% more electricity for the same cooling.
4Duct leaks
If your ductwork has leaks (very common in Houston attics where the extreme heat degrades duct tape and connections), you're paying to cool your attic instead of your house. Duct leaks can waste 20–30% of conditioned air.
5Thermostat issues
A miscalibrated thermostat can cause the system to run more than needed. If the thermostat thinks it's warmer than it actually is, the system overcools.
6System running non-stop
Check if the fan is set to ON instead of AUTO. When set to ON, the blower runs 24/7 even when the compressor isn't cooling — adding significant electricity usage.
DIY Troubleshooting
What You Can Try
Replace the air filter
This is free or close to it, and it's the most common efficiency killer. Replace it and monitor your usage for the next billing cycle.
Check the thermostat fan setting
Make sure the fan is set to AUTO, not ON. ON mode runs the blower continuously — that's hundreds of extra hours of motor runtime per month.
Compare billing period temperatures
Check if this month was hotter than last year's same month. A few degrees of average temperature difference can significantly impact your bill. This may not be a problem at all — just a hotter month.
Check your vents and returns
Make sure all vents are open and unobstructed. Closing vents in unused rooms actually makes the system less efficient, not more.
Schedule a tune-up
A professional maintenance visit cleans coils, checks refrigerant levels, verifies airflow, and identifies efficiency problems. It typically pays for itself in the first month's savings.
Know When to Call
When to Call a Pro
If your bill has spiked 30% or more over the same period last year and the filter isn't the cause, get a professional assessment. A tech can measure actual system efficiency, check for refrigerant leaks, test ductwork for leaks, and determine if the system is worth repairing or if it's time for a more efficient replacement.
Pro Tip
In Houston, a well-functioning AC should cycle on and off — running about 15–20 minutes per cycle, 2–3 times per hour on a hot day. If your system runs constantly without cycling off, it's either undersized for your home, struggling with an efficiency problem, or your house has insulation/duct issues that no AC can overcome.
Need a Pro?
Services That Solve This
Preventive Maintenance
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Learn moreNew System Installation
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