07/20/2026
Houston humidity is not just uncomfortable. It is actively working against your AC system. and most homeowners don't see it
happening until something fails.
Here's the mechanism and why Houston is one of the most demanding environments for residential HVAC in the country.
When outdoor relative humidity sits at 75 to 95%. which it does reliably from June through September. Your AC is managing a
Dual load simultaneously: removing heat AND removing moisture from the air. This is significantly more demanding than
dry-weather cooling, where the system primarily handles heat load alone.
What happens when your system can't keep up with both:
Indoor relative humidity stays above 55 to 60% even with the AC running. At those levels, mold begins colonizing organic
surfaces within 24 to 48 hours. drywall, wood framing, carpet backing, and ceiling tiles. You smell it before you see it. That musty
The odor when the AC turns on is almost always early mold in the evaporator coil or drain pan.
The four failure patterns we see every Houston summer driven by humidity:
1. Clogged drain lines from condensation volume overwhelming a partially blocked drain
2. Frozen evaporator coils from mold-restricted airflow reducing heat transfer
3. Mold contamination spreading from the air handler into connected ductwork
4. Compressor stress from short-cycling on heavy humidity days
Annual maintenance catches all four before they become failures.
An $89 tune-up includes drain line treatment, full coil cleaning, and a complete airflow inspection. the exact services that
Address humidity-related damage before it compounds.
If your Houston AC hasn't been serviced in the last 12 months, it has humidity damage building inside it right now.
Call (713) 598-2737 or book at 75degreeac.com.
