By Tommy, Comfortable LLC field technician · September 2, 2026 · Indoor Air Quality
Memphis and the Mid-South don't just get hot in the summer — the humidity is what really makes a system work for its money. We see the effects of that every summer on service calls across Collierville, Germantown and Memphis, and it changes what "comfortable" actually requires here compared to a drier climate.
Why humidity makes your AC work harder
An air conditioner does two jobs at once: it cools the air, and it pulls moisture out of it as air passes over the cold coil. In a humid climate, that second job is a much bigger load. A system that's sized correctly for temperature alone can still leave a home feeling muggy, because it satisfies the thermostat and shuts off before it's run long enough to remove enough moisture.
Signs humidity is winning in your home
- The house feels sticky or clammy even when the temperature reads where you want it
- Condensation on windows or cold surfaces
- A musty smell, especially near vents or in the basement
- Visible mold or mildew on ductwork, in closets, or around windows
If you're noticing any of these, it's not just a comfort issue — sustained excess moisture is also what lets mold take hold indoors.
What actually helps
Correct system sizing
An oversized system is one of the most common causes of a home that's cold but still humid. Correct sizing (a real load calculation, not a rule of thumb) lets the system run longer cycles that actually remove moisture.
In ACCA terms, that means a real Manual J load calculation for your house — not a rule of thumb based on square footage alone. Mid-South humidity adds a large latent (moisture) load. A Manual J that only chases the thermostat number can still leave you with an oversized unit that short-cycles, cools the air, and never runs long enough to wring out the moisture. When we size or replace equipment, we also look at duct design (Manual D) so the system you buy can actually deliver the airflow the calculation assumes.
A whole-home dehumidifier
Paired with your existing AC, a dedicated dehumidifier handles the moisture load directly, which matters most during the shoulder seasons when it's mild but still muggy and the AC doesn't run much.
Sealed, insulated ductwork
Leaky ducts pull humid attic or crawlspace air into your system, undoing the work your AC is already doing. Sealing and insulating ductwork is often an overlooked fix.
Regular coil and drain maintenance
A dirty coil or a clogged condensate drain line makes moisture removal worse and can cause water damage. A seasonal tune-up catches this before it becomes a bigger problem.
When it's more than normal humidity
If you're seeing actual mold growth, water intrusion, or a musty smell that doesn't go away, that's worth a professional look rather than just running a portable dehumidifier. We handle indoor air quality and duct cleaning & sealing across the Mid-South, and can tell you honestly whether the fix is a dehumidifier, duct sealing, or something with the system itself.
FAQs
Why does my house feel humid even when the AC is running?
An oversized AC cools the air quickly without running long enough to remove much moisture, since dehumidification happens gradually as air passes over the coil. A properly sized system, or a dedicated whole-home dehumidifier, fixes this.
Do I need a whole-home dehumidifier in Memphis?
If your home feels sticky even with the AC running, you notice condensation on windows, or you smell must, a whole-home dehumidifier paired with your existing system is usually worth it in the Mid-South's long, humid cooling season.
Can high humidity damage my HVAC system?
Yes — excess moisture makes coils and drain lines work harder all summer, which can lead to condensate drain clogs, mold growth in ductwork, and added strain that shortens equipment life.