The last piece of a proper encapsulated crawlspace. We size the unit to your cubic footage (not by guess), plumb the condensate line to daylight or a sump, and dial in the humidistat so your crawlspace holds a steady 50-55% RH year-round.
A licensed local crew — usually out in 24 to 72 hours. Written scope, fixed price, no pressure.
Dehumidifier installs in Stallings mostly happen as part of a full encapsulation, but I also get a fair number of calls from homeowners who want to add a proper commercial dehumidifier to a crawl that was previously partially treated — usually a Chestnut or Idlewild Rd house where the builder ran 10-mil plastic and wrapped a few piers in 2005 and skipped the dehumidifier entirely. Those homeowners are paying real money to condition a crawl that is still climbing to 75 percent RH by August because the moisture-removal side of the equation was never installed. Dropping in a properly sized Aprilaire or Santa Fe on a dedicated circuit finishes what the builder started.
Last summer I got called out to a 2006 two-story in Chestnut off Old Monroe Rd. Owner had a builder-attempted partial encap from original construction — 10-mil ground plastic mostly intact, four pier wraps out of 22 total (the ones visible from the hatch, obviously done for the sales-office walk-through), open vents, no dehumidifier. She had lived in the house 12 years and finally called because the master bedroom above the garage-slab-over-crawl transition was uncomfortably muggy in July even with the AC running. My hygrometer in the crawl read 78 percent RH at 10 in the morning. The plastic was still functional on the ground, the piers she had wrapped were still holding. The problem was the missing dehumidifier and the open vents that were still pumping outdoor Union County humidity into the crawl every day from May through September.
Scope on that house was smaller than a full re-encapsulation. Sealed the ten open vents with closed-cell foam blocks and exterior mechanical covers. Wrapped the remaining 18 piers that the builder had skipped. Installed an Aprilaire E100 sized for the 3,200 SF crawl footprint on a new dedicated 20-amp circuit, discharge to daylight through the south wall, humidistat set to 55 percent. Two days on site including the electrical permit inspection through Union County. Six weeks later the RH was holding at 54 to 56 percent and the master bedroom was noticeably drier. That is the dehumidifier-as-finishing-scope job — pretty common in Stallings on the 2000s Chestnut and Idlewild Rd stock.
The other flavor is the standalone dehumidifier install on a vented crawl as a moisture-management interim step before full encapsulation. This is a less-common scope because a dehumidifier in a vented crawl is running against the whole atmosphere of Union County — it will lower the RH some but it will not hold 55 percent because outdoor air keeps flowing in through the open vents. On some houses it makes sense as a bridge scope until the full encapsulation budget is available. I explain the tradeoffs and let the homeowner decide. What follows is what a real dehumidifier install looks like on a Stallings house, how sizing works, and what the pitfalls are. Free on-site inspection with a cubic-footage calc and a moisture-load estimate. No prices in here — those come after the inspection.
Dehumidifier sizing in Stallings is by cubic footage of the sealed crawl volume plus a moisture load estimate based on the current condition of the vapor barrier, vent seal status, and any active water intrusion. Cubic footage first: length by width by average clearance. Emerald Lake and older Ashe Plantation 90s tract at 2,200 to 3,000 SF footprint with 38-inch clearance calculates out to 7,000 to 9,500 cubic feet of crawl volume. Chestnut and larger Idlewild Rd 2000s customs at 3,200 to 4,500 SF footprint with 42 to 46 inch clearance run 11,000 to 17,000 cubic feet. The dehumidifier sizing tables published by Aprilaire and Santa Fe are based on daily pints of moisture removal at 80 degrees and 60 percent RH — I use those tables as the starting point and adjust based on the crawl's actual condition.
Under-sizing is where the fast-flip franchises trap homeowners. A residential portable rated at 50 pints per day gets installed in a 12,000 cubic foot Chestnut crawl, runs 24 hours a day trying to hold 55 percent RH, burns out its compressor inside two summers, and never actually gets the RH below 68 percent because the moisture load exceeds the pump-down capacity. Commercial units at 70, 90, or 100-plus pints per day sized correctly for the crawl volume hold 55 percent through August with maybe 60 percent duty cycle, which is what those units are designed for.
Placement matters. Unit gets mounted on a stand or hung from the joists in a central location where the return air can pull from the whole crawl and the supply discharge is not blowing directly at a wall or into a duct chase. On a rectangular Stallings crawl that means roughly center of the footprint, elevated a few inches off the ground plane so the drain pan gets airflow underneath. Never sitting directly on the vapor barrier — it will get walked on, kicked, or pulled sideways over time and eventually damage the barrier below it.
Drain is either gravity-to-daylight or to a condensate pump. Gravity is preferred when the lot has enough slope for a 1/4-inch-per-foot fall from the unit to a daylight exit through the block wall — that works on maybe 60 percent of Stallings houses where the yard drops enough on one elevation. On the flatter Old Monroe Rd corridor lots where gravity does not cooperate, we install a condensate pump (Little Giant or Hartell brand, 120V) that lifts the discharge up and out through the rim joist, then to a splash block or landscape bed 10 feet from the foundation. Never discharge into the sanitary sewer without a p-trap and an air gap — that is a code violation everywhere in Union County.
Electrical is a dedicated 20-amp circuit on the crawl-side of the panel, filed under a Union County electrical permit through the county building department in Monroe. Never share the circuit with the crawl light or any other load — if something trips at 2 AM in July you want the dehumidifier still running. Circuit gets a GFCI outlet in the crawl, mounted above the flood plane. Inspection happens after the circuit is landed and the unit is wired in. We schedule it, meet the inspector, and hand you the signed-off card.
Humidistat setting is 55 percent RH. Not 60. Not 50. 55 is the sweet spot for a Union County crawl in summer — high enough that the unit is not running continuously and burning through its compressor, low enough to prevent condensation on cold surfaces and inhibit mold growth. Modern Aprilaire and Santa Fe units have built-in digital humidistats accurate to 2 percent RH. Third-party remote humidistats are optional but not required.
Small-crawl workhorse for Emerald Lake and older Ashe Plantation stock at 7,000 to 10,000 cubic feet: Aprilaire E080 or Santa Fe Compact 70. Both are 70-pint-per-day commercial units with built-in condensate pumps, digital humidistats, and MERV 8 filtration on the return. Aprilaire E080 has a slightly better track record on repairability in this market — parts are stocked at three or four HVAC supply houses in the metro. Santa Fe Compact 70 is quieter if the crawl is directly under a bedroom and noise transmission matters.
Mid-size for larger Ashe Plantation or smaller Chestnut houses at 10,000 to 13,000 cubic feet: Aprilaire E100 at 100 pints per day. Same feature set as the E080, just more capacity. Handles the moisture load on a 3,000 to 3,500 SF crawl with reasonable duty cycle through Union County summer.
Large-crawl units for bigger Chestnut and Idlewild Rd customs at 13,000 to 18,000 cubic feet: Santa Fe Ultra98 (98 pints per day, MERV 13 filtration) or AlorAir Sentinel HDi90. Both are commercial-grade with heavy-duty compressors rated for continuous residential duty. AlorAir is a slightly lower price point with a solid track record — I have installed a couple dozen in the metro over the past four years and warranty claims have been rare.
Drainage hardware is either 1/2-inch clear vinyl gravity discharge tubing (when the lot slopes enough for daylight discharge) or a Little Giant VCMA-15ULS condensate pump wired into the same GFCI circuit as the dehumidifier (when the lot is flat and gravity will not work). Pump discharge is 3/8-inch clear vinyl tubing routed up through the rim joist and out through a PVC bulkhead in the sill, then to a splash block or landscape bed 10 feet from the foundation.
Electrical is a dedicated 20-amp circuit filed under a Union County electrical permit. GFCI outlet in the crawl, mounted above the flood plane on a pressure-treated 2x4 backer lag-bolted to the block wall. Whip from the outlet to the dehumidifier is 12-gauge SJ cord with proper strain relief at both ends.
Filter replacement is annual, MERV 8 or MERV 13 depending on the unit. Aprilaire E080 uses the Aprilaire 219 filter. Santa Fe Compact 70 uses the Santa Fe 4028372 filter. Both are stocked at HVAC supply houses in Charlotte and Matthews. Homeowner can replace them, or we do it as part of an annual maintenance visit.
Yes — Stallings is a regular dehumidifier route. Free on-site inspection anywhere in Stallings, fixed written quote before we touch anything.
Dehumidifier as a standalone finishing scope on top of an existing builder partial encapsulation is more common in Stallings than in Matthews or Mint Hill because Chestnut and Idlewild Rd 2000s custom builds got the partial-encap treatment from the builder at a rate you do not see in the older or tighter neighboring markets, and finishing those jobs with just the dehumidifier and vent seal is a legitimate targeted scope.
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You can, and I will tell you honestly what happens if you do. Residential portables rated at 50 or 70 pints per day are designed for occupied living spaces with 2 to 4 person moisture loads, not the constant 24-hour duty cycle of a sealed crawlspace pulling moisture out of the ground and the framing. Even the best residential portable will burn out its compressor inside two summers of continuous crawl duty, and it will never actually hold 55 percent RH because the pump-down capacity is not matched to the crawl volume. Commercial units — Aprilaire, Santa Fe, AlorAir — are designed for exactly this application, use heavier compressors and better filtration, and run 8 to 12 years in typical service. The unit cost difference is real but the total cost of ownership over 10 years favors the commercial unit by a wide margin.
Depends on the unit and the crawl condition, but a properly sized Aprilaire E080 running maybe 40 to 60 percent duty cycle in a sealed Stallings crawl through the summer draws a modest but real chunk of power from May through September, and much less the rest of the year when duty cycle drops way down. Bigger units in bigger crawls scale proportionally. In practice, a lot of homeowners see the AC upstairs run less because the crawl is no longer feeding humid air into the house via stack effect — so total household electric consumption during summer often ends up net-lower with the dehumidifier running than it was without. Not always, but often.
Yes, and this is the finishing-scope work I described in the intro. Builder partial encaps from that era in Chestnut always skipped the dehumidifier because it was outside the scope the builder was willing to sell for the price point. Without a dehumidifier the crawl still runs 70 to 80 percent RH through summer even with the partial vapor barrier in place, because moisture-laden outdoor air is still coming in through open or poorly sealed vents and there is no active removal mechanism. Dropping in a properly sized Aprilaire E080 or E100 on a dedicated circuit, plus sealing the vents that were not sealed originally, finishes the encapsulation and gets the crawl to hold 55 percent RH through August. Two days of work, one Union County electrical permit, done.
No, and if it is running continuous, the sizing was wrong. A properly sized commercial dehumidifier in a sealed Stallings crawl runs about 40 to 60 percent duty cycle from May through September, cycling on and off to hold 55 percent RH. Duty cycle drops way down in shoulder seasons and can be nearly zero in winter when the outdoor dew point is low enough that the crawl stays dry on its own. If your dehumidifier is running 24 hours a day and still not holding 55 percent RH, either the unit is undersized for the crawl volume or there is an active moisture source (leaking plumbing, missing vent seal, saturated ground from an exterior drainage problem) that needs to be addressed independently. Free on-site inspection can diagnose which.
Free on-site Stallings inspection. Fixed written quote. Call (980) 227-1769 or book below.