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AC Not Cooling the House
in Lewisville, TX
In Lewisville, summers push outdoor temperatures above 100 degrees for weeks at a time. When your AC can't keep up, it's rarely just the thermostat. If you leave it alone, the compressor works harder than it should and can fail completely.
Quick Answer
When your AC runs but can't cool your home in Lewisville, it's usually a refrigerant problem or a dirty coil blocking heat transfer. A technician needs to check the refrigerant level and inspect the evaporator coil. Don't ignore it during a North Texas summer — indoor temps can climb fast. Call (361) 401-8806 to schedule an inspection.
Telltale Signs
Warning Signs to Watch For
- The thermostat is set to 72 but the house sits at 82 or higher
- The AC runs constantly without shutting off
- Warm air blows from the vents even when the system is on
- The indoor air feels humid and sticky, not just warm
- Electric bills jump even though your habits haven't changed
- Ice forms on the copper lines near the indoor unit
Root Causes
What Causes AC Not Cooling the House?
Low Refrigerant From Leak
Refrigerant absorbs heat inside your home and releases it outside. When there's a leak, the system loses its ability to move heat and the house stays warm no matter how long the AC runs. Older systems installed in the early 2000s in neighborhoods like Castle Hills often use R-22 refrigerant, which is no longer made and harder to service.
The Fix
Leak Detection and Refrigerant Recharge
A technician finds the leak using a detector or UV dye, seals it, and recharges the system to the correct level. Simply adding refrigerant without fixing the leak is a short-term fix that won't hold.
Dirty Evaporator Coil
The evaporator coil sits inside your air handler and pulls heat out of the air. When it gets coated in dust and debris — which happens fast in Lewisville's dry, dusty summers — it can't absorb heat properly and the house stays warm. This usually happens when filters aren't changed regularly.
The Fix
Evaporator Coil Cleaning
A technician removes the coil access panel, cleans the coil with a foaming cleaner, and flushes the drain line. A clean coil transfers heat the way it's supposed to.
Undersized or Failing Compressor
The compressor is the pump that keeps refrigerant moving through the system. If it's failing or was undersized when the system was installed, it can't move enough refrigerant to cool the house on a 103-degree day in Lewisville. You'll hear it struggling — a grinding or hard-start noise — before it quits completely.
The Fix
Compressor Replacement or System Replacement
If the compressor is gone, replacing just that part often costs nearly as much as a new outdoor unit. A technician can tell you which makes more sense based on the age and condition of the rest of the system.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Low Refrigerant From Leak | Dirty Evaporator Coil | Undersized or Failing Compressor |
|---|---|---|---|
| Ice on the refrigerant lines or indoor coil | |||
| Warm air from vents, system runs constantly | |||
| Grinding or hard-start noise from outdoor unit | |||
| High humidity indoors with poor cooling | |||
| Spike in electric bill with no change in usage |
Free Inspection
Get a Diagnosis in Lewisville
An on-site inspection is the only way to confirm which cause applies to your property. Free, no obligation.
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