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.
Every single 2000s-era house in Marvin Creek, Longview, Firethorne, and Providence Downs South was built without a crawl dehumidifier. Every one. The builders in that Waxhaw 2001-2015 boom window ran open-vent block perimeter crawls with builder-grade 6-mil vapor barrier and stapled fiberglass batts, called it code-compliant, and moved on. Nobody dropped a Santa Fe or an Aprilaire into a Marvin Rd crawl at construction time — that just wasn't the standard. Fifteen to twenty years later basically every one of those homes needs a dehumidifier added, usually as part of a full encapsulation because a dehumidifier in a still-vented crawl just runs continuously chasing outside air.
The dehumidifier retrofit that comes to mind is one I did in Longview off Waxhaw Marvin Rd this past July. 2006 build, 4,800 sq ft custom, 4-foot crawl clearance. Owner had already done a partial encapsulation herself a few years earlier — she'd pulled the fiberglass out (or paid someone to), had a decent 12-mil ground liner installed, but the vents were still open and there was no dehumidifier. Crawl was at 82% RH in July, dew point at 71 degrees, and she was starting to see the same condensation-on-cold-ducts problem that the fully-vented houses have. What she needed was to seal the 12 vents around the perimeter, upgrade the ground liner to 20-mil YellowGuard (the 12-mil was already showing tears from HVAC service), and drop in a Santa Fe Ultra98 sized for her cubic footage. Two-day install, Union County electrical permit for the dedicated 20-amp circuit, condensate pumped out to a French drain 20 feet from the foundation. Follow-up read at 45 days was 51% RH — exactly where we want it.
Downtown Waxhaw dehumidifier work is a smaller footprint but the same physics. Historic homes on Main St, Broome St, McDonald St typically run 1,200 to 1,800 sq ft crawl footprints with 18-24 inches of clearance. Aprilaire E070 handles that size easily. The install challenge is fitting the unit into a low-clearance crawl and routing the condensate through an HDC-approved exterior penetration, which usually means threading it through an existing chimney chase or utility penetration to keep it invisible from Main St. Different mechanical challenge, same product philosophy.
Any Waxhaw dehumidifier install starts with a cubic footage calculation and moisture load assessment. Sizing wrong is the most common mistake I see on lower-tier installs — undersized units run continuously in July and August and still can't hold 55% RH, oversized units short-cycle and don't dehumidify efficiently. Cubic footage is length x width x average clearance height. Moisture load adjusts based on how leaky the crawl is (fewer sealed vents = higher load), whether there's active water intrusion, and whether the barrier is 20-mil (low load) or older 6-12 mil (higher load). For a typical Marvin Creek or Longview 4,000-5,500 sq ft footprint with 4-foot clearance and a properly sealed encapsulation, that's 16,000 to 22,000 cubic feet, which sizes to a Santa Fe Ultra98 comfortably. For a 6,000-7,500 sq ft Firethorne estate with the same clearance, that's 24,000 to 30,000 cubic feet, which needs an AlorAir HDi100 or a dual-unit Santa Fe install.
Install sequence: identify a location in the crawl with adequate clearance for the unit and its service access (Santa Fe Ultra98 needs 24 inches of clearance around three sides for filter changes and service, Aprilaire E070 is more compact and can tuck into tighter corners), mount to a small platform or hang from the joists depending on unit and clearance. Run a dedicated 20-amp circuit from the electrical panel — Union County requires a licensed electrician for this and pulls a permit through the county office in Monroe. Route condensate to either a French drain 20+ feet from the foundation (preferred where lot allows), a condensate pump to an existing plumbing stack (fallback when gravity discharge isn't possible), or in downtown historic homes through an existing chimney chase or hidden utility penetration to satisfy HDC review. Set the humidistat to 55% RH discharge. First-year filter change interval is 6 months on a new install as the crawl equilibrates; steady-state is annual after that. All Waxhaw dehumidifier installs come with a 30-day follow-up RH read to verify performance.
For Marvin Creek, Longview, and standard Firethorne 4,000-5,500 sq ft footprints: Santa Fe Ultra98 (98 pints/day at AHAM conditions, 250 CFM airflow, MERV-13 filter, 6.6 amps at 115V). It's the workhorse for luxury Waxhaw stock and it holds 50-55% RH reliably through August with a typical duty cycle of 30-40% during peak summer. For larger 5,500-7,500 sq ft Firethorne and Providence Downs South estates: AlorAir HDi100 (100 pints/day, 300 CFM, MERV-13, 7.2 amps at 115V). Similar performance envelope with slightly higher airflow. For truly huge 7,500+ sq ft custom builds I've done in Firethorne, dual Santa Fe Ultra98 units on separate circuits, both discharging to a common French drain.
Downtown Waxhaw historic homes with 1,200-1,800 sq ft crawl footprints: Aprilaire E070 (70 pints/day, 155 CFM, MERV-13, 5.8 amps at 115V). Compact enough to fit in a 20-inch clearance crawl and quiet enough that it doesn't transmit noise up through the wood floors of the historic homes. Aprilaire E100 (100 pints/day) is the alternate if the downtown home is larger than 1,800 sq ft or has active moisture load from a nearby drainage issue. All units get MERV-13 filtration standard — the crawl air is what feeds the house via stack effect, so filtration quality matters for indoor air quality even though the unit is under the house.
Humidistat setpoint is 55% RH discharge, factory default. Condensate discharge: 3/4-inch PVC to a French drain 20+ feet from the foundation preferred, condensate pump (Little Giant VCMA-15UL or Aspen Mini Orange) as fallback for gravity-limited situations. Dedicated 20-amp electrical circuit required — Union County permit and licensed electrician on every install.
Yes — Waxhaw is a regular dehumidifier route. Free on-site inspection anywhere in Waxhaw, fixed written quote before we touch anything.
Waxhaw dehumidifier work is dominated by retrofits into 2000s Marvin Rd luxury builds — Marvin Creek, Longview, Firethorne, Providence Downs South — where the builders skipped dehumidifiers entirely and every 15-20 year old house now needs one. Downtown historic dehumidifier installs are smaller units in tighter crawls with HDC-routed condensate lines.
28173. All Union County addresses covered.
Because the 2000s NC building code allowed vented crawlspaces and didn't require dehumidification for compliance. Builders in the Marvin Rd 2001-2015 boom window all followed the same playbook: vented block perimeter, 6-mil ground plastic, stapled fiberglass batts in the joist bays, no dehumidifier. That approach was code-compliant when your house was built. It was also wrong for the Waxhaw climate — 65 to 75 degree dew points from May through September mean vented crawls run 80%+ RH for most of the summer, which drives condensation, mold, wood decay, and HVAC efficiency loss. The 2018 NC Residential Code allowed sealed conditioned crawlspaces specifically because the vented approach kept failing. Every 2000s Marvin Creek, Longview, Firethorne, and Providence Downs South house is now due for encapsulation with a dehumidifier.
Technically yes, practically no. A dehumidifier in a still-vented crawl will run continuously trying to dehumidify outside air that's constantly flowing through the vents, and it will still never hit 55% RH in a Waxhaw July. It's basically an air conditioner running with the windows open — a lot of energy consumed for negligible result, plus rapid wear on the unit. For any real moisture control in a Waxhaw crawl you need the full package: sealed vents, 20-mil ground liner, individually wrapped piers, mechanical wall termination, and then the dehumidifier. If budget is a constraint I can do a phased install (barrier and vent seal first, dehumidifier in year two), but running a dehumidifier alone in a vented crawl is throwing money at a problem that will never solve.
A Santa Fe Ultra98 running at typical Waxhaw summer duty cycle (30-40% during peak, dropping to 10-15% shoulder seasons, near zero in winter) draws about 5-8 kWh per day during peak season, dropping to 1-2 kWh per day in the shoulder months. At Duke Energy residential rates that's a modest monthly cost in July-August and near zero in December-February. Annualized it's typically less than the HVAC efficiency gain you get from not conditioning a swampy crawl through leaky return ducts — the encapsulation and dehumidifier system usually pays for itself in HVAC savings within 3-5 years, before you count the resale value bump and the mold prevention.
First year on a new install: change the MERV-13 filter at 6 months. The initial crawl is going to have a higher particulate load as everything settles out, and the fresh install kicks up dust during the install itself. Steady-state after year one: annual filter change is fine for most Waxhaw installs. If you have pets in the house, active construction nearby, or any known dust sources, drop to every 6 months permanently. Filter changes are a homeowner task if you're comfortable in the crawl — I show every customer the location and the swap process at commissioning. We also offer an annual service check for anyone who'd rather have us handle it.
Free on-site Waxhaw inspection. Fixed written quote. Call (980) 227-1769 or book below.