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High Humidity Inside the Home
in Frisco, TX
An AC does two things — it cools the air and it removes moisture from it. In Frisco, the humidity that comes in from the south in April and May can push indoor relative humidity above 60 percent even with the AC running. At that level, mold starts growing inside walls, under baseboards, and in the attic within a few weeks.
Quick Answer
When your AC runs but the air inside still feels sticky, the system is not removing enough moisture. In Frisco, spring months bring dew points above 65 degrees, and an AC that is too large, short cycling, or low on refrigerant will cool the air without drying it properly. High indoor humidity feeds mold growth in walls and under flooring. Call (254) 279-4716 if the problem does not clear up when temperatures rise and the system runs longer cycles.
Telltale Signs
Warning Signs to Watch For
- The air inside feels heavy and damp even with the AC running
- Condensation forms on windows, mirrors, or cold surfaces
- A musty smell in certain rooms or in closets
- Wood floors or cabinet doors are swelling or warping
- Visible mold spots forming on walls or bathroom ceilings
- Indoor humidity reading above 55 percent on a hygrometer
Root Causes
What Causes High Humidity Inside the Home?
Oversized System Running Short Cycles
An AC removes humidity by running long enough for moisture to condense on the evaporator coil and drain away. A system that is too big for the house cools the air fast and shuts off before it has done much dehumidifying. A lot of homes in newer Frisco developments built between 2010 and 2020 have this problem because systems were sized for cooling load without enough attention to moisture removal.
The Fix
System Right-Sizing or Dehumidifier Addition
The right fix depends on how oversized the current system is. A whole-home dehumidifier can be added to the existing system to handle moisture independently of the cooling cycle, which is often the faster solution without replacing the unit.
Low Refrigerant Reducing Coil Performance
A properly charged evaporator coil runs cold enough that moisture from the air condenses on it and drains out. When refrigerant is low, the coil does not get cold enough to pull moisture effectively, and humidity passes right through into the living space. This problem is gradual and homeowners often notice the stickiness before they notice the cooling loss.
The Fix
Refrigerant Leak Repair and Recharge
Restoring the correct refrigerant charge brings the coil temperature back down to where it can condense moisture properly. A technician should verify the leak is sealed first so the charge does not bleed off again.
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 | Oversized System Running Short Cycles | Low Refrigerant Reducing Coil Performance |
|---|---|---|
| Humidity is high but house cools to the set temperature quickly | ||
| Humidity is high and house also struggles to cool | ||
| Problem worse in spring when outdoor dew point is high | ||
| Musty smell and humidity problem appeared slowly over one season | ||
| System short cycles frequently throughout the day |
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