New Construction AC Repair and Sizing in Summerville, SC
A brand-new home that runs cool but feels sticky almost always has a sizing problem, not a thermostat problem. Here is why builder-grade systems in our planned communities struggle with Lowcountry humidity, and how to fix it the right way.
Call (843) 708-8735Thousands of Summerville homes, the same sizing shortcut
Summerville's planned-community boom put up entire neighborhoods on the same playbook, builder-grade air conditioners spec'd to a square-footage rule of thumb to keep costs down. Those systems are now hitting their first warranty expirations and first major repairs in waves, all at once, across the same subdivisions.
Why a brand-new home still feels sticky
It feels backwards. The house is new, the AC is new, the thermostat reads 72, and the air still feels damp. The cause is how the system was sized.
Sized for the thermostat
Builders pick the least expensive unit that clears a square-footage rule of thumb. That rule targets temperature, the sensible heat, and largely ignores the Lowcountry's heavy humidity load. In a tight, well-sealed new home the unit cools the air to setpoint fast, then shuts off.
Sized for our humidity
An AC only pulls moisture out while it runs. When it satisfies the thermostat in short bursts and short-cycles, it never runs long enough to wring the humidity out of the air. The result is a home that is cool but clammy. Right-sizing fixes the run time, and the dehumidification follows.
The fix starts with a real load calculation
A Manual J load calculation is the industry-standard sizing method from the ACCA. Instead of a rule of thumb, it accounts for your home's square footage, insulation, window count and orientation, air infiltration, and, critically here, the latent load, which is the energy it takes to remove humidity. Weighted for our climate, a Manual J usually lands on a different size and configuration than the builder default, one that runs longer and dries the air out as it cools.
What to ask your builder or warranty contractor
- Was a Manual J load calculation performed for my home, and can I see it?
- What is the sensible versus latent split it was sized for?
- What indoor humidity should I expect at design conditions?
- Was the ductwork sized with a matching Manual D, or carried over from the plan?
- If the system short-cycles, what is the warranty remedy?
When the answer is a dehumidifier, not a bigger unit
It is tempting to assume a humid house needs more cooling power. When a system is already close to right-sized, which is the usual case in new construction, the opposite is true. A larger unit cools even faster, short-cycles even harder, and removes less moisture, not more.
The cleaner fix is a whole-home dehumidifier ducted into the system. It handles humidity independently, so your AC can run for temperature alone and the house finally feels dry. The one exception is a system that genuinely cannot keep up, running nonstop and never reaching setpoint, where a proper resize is the right call. We measure first and tell you honestly which your home needs.
How to handle a warranty claim on a near-new system
Most builder-installed systems carry a manufacturer parts warranty, often ten years, plus a shorter builder or labor warranty. The coverage is real, but it has rules. Here is how to keep it intact and use it.
Find your model, serial, and install date
They are on the data plate at the outdoor unit and on your closing paperwork. You need them for any claim.
Confirm the registration
Many manufacturer warranties drop from ten years to five unless the system was registered shortly after install, typically within 60 to 90 days, though the exact window varies by brand. We can look up your deadline and register the system if it is still open.
Know what is covered
Parts are usually covered for the full term. Labor often is not after the first year. Knowing the split tells you what a repair will actually cost out of pocket.
Use a licensed contractor and keep records
Unlicensed or DIY repairs, and skipped maintenance, can void coverage. We make warranty-valid repairs and document them, so the warranty stays good for the next claim.
New construction AC FAQ
Cool but sticky in your new Summerville home? Let us size it right.
We will measure your home, run a humidity-weighted load calculation, check your warranty, and tell you straight whether the answer is a repair, a dehumidifier, or a resize. No pressure, just the honest call.
Call (843) 708-8735