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.
Last August I did an emergency service call on a 2004 subdivision home off Sardis Rd, on the Matthews side near the Stallings town line. The homeowner had received a text from his HVAC company that his warranty was going to be voided because their annual service tech had documented 78 percent RH under the crawlspace, well above the 60 percent threshold in the warranty terms. He had a builder partial encapsulation from original construction — 6-mil plastic on the ground, sealed vents, but no dehumidifier. He had lived there 20 years and had never seen the crawl.
Under the house: 38 inches of clearance, block perimeter foundation, six interior block piers, the original 6-mil plastic in decent condition for its age but no wall liner and — critically — no dehumidifier. Humidity meter read 82 percent in the crawl at the time of my inspection. He had been running the HVAC hard all summer trying to hold the first floor comfortable and had no idea half the moisture load on his AC was coming from the crawl through stack effect. Fix was a Santa Fe Ultra98 sized for the 2,400 SF crawl footprint, dedicated 20-amp electrical circuit, condensate drained to daylight through the west foundation wall, and finishing the builder partial encapsulation with 20-mil ground liner and mechanical wall termination. Humidity was under 50 percent within 72 hours.
The dehumidifier is the single most important piece of equipment in a Charlotte crawlspace and it is also the single piece that Matthews builder partial encapsulations from the 90s and 2000s always skipped. On the 2000s subdivisions along Independence Blvd and out to Weddington Chase I finish partial builder encapsulations that never had a dehumidifier almost every week — probably a third of my Matthews jobs are this scope. On the older 1970s-80s split-level tract along Sam Newell, Sardis, and John St, adding a dehumidifier to an existing vented crawl is a different scope but same result — the dehumidifier is what actually holds the crawl under 55 percent RH through a Charlotte summer where dew points hover in the low 70s from June through September.
Free on-site inspection anywhere in Matthews and out to Mint Hill, Stallings, Weddington, and Indian Trail.
The process on a Matthews dehumidifier install branches based on whether it is a retrofit into an existing crawl envelope or part of a full new encapsulation.
Sizing and placement. First step on any Matthews inspection is measuring the crawl cubic footage (square footage times average clearance height) and checking existing moisture load with a hygrometer. On a tight 1,600 SF Matthews split-level crawl the sizing usually lands on an Aprilaire E070 or Santa Fe Compact 70. On a 2,400 SF Weddington-side subdivision home it goes to a Santa Fe Ultra98 or AlorAir Sentinel HDi90. Undersizing is the most common mistake I see on competitor installs — a unit that cannot hit setpoint runs continuously, wears out fast, and never actually reaches the target RH. Oversizing is not really a problem in Charlotte's aggressive humidity environment because the unit will just short-cycle less. When in doubt I round up.
Placement in low-clearance crawls. On Matthews split-levels with 22 inches of clearance, unit placement is constrained by two things: enough working room to change the filter without a spelunking expedition, and enough clearance for the unit's air intake and discharge to work properly. The Aprilaire E070 has a slim horizontal profile that fits under most Matthews split-levels but the Santa Fe Compact 70 is taller and sometimes has to be placed at the crawl entry rather than in the interior. I map the placement on the inspection before writing the scope so the homeowner knows exactly where the unit will sit and how filter changes will work.
Electrical. Dedicated 20-amp circuit is required for any dehumidifier we install — never share with the crawl light, never run off an extension cord from a nearby outlet. That is a Mecklenburg electrical permit and we pull it through CityInspect.charlottenc.gov. Union County (Stallings and Weddington side) is the same standard. On Matthews split-levels the electrical panel is usually in the garage or in an interior utility closet, and the run to the crawl adds meaningful electrical labor to the scope. On the 2000s subdivisions the panel is often already in a location that makes the run short.
Condensate management. Dehumidifier discharges 15 to 25 gallons of water per day in peak Charlotte summer humidity on a properly sized unit. That water has to go somewhere. Best option is gravity drain to daylight through the foundation wall — a 3/4-inch PVC line pitched at 1/8 inch per foot to a discharge point outside the foundation. On Matthews split-levels where the crawl elevation is close to grade, gravity drain works. On some houses where the crawl is deeper or the discharge exit is uphill, we use a condensate pump (Little Giant VCMA-20ULS is our workhorse) to lift water to the outside. Pump adds a failure point but is sometimes the only option.
Humidistat and setpoint. Discharge humidistat is factory-set to 55 percent RH on the Aprilaire and Santa Fe units and I leave it there for most Charlotte jobs. Some homeowners want tighter — 50 percent or even 45 percent — which is achievable but consumes more electricity. On Matthews split-levels where the crawl envelope has to handle both the tight sealed-vent zone and the leaky-hatch zone near the crawl entry, 55 percent is a good target that the unit can hit reliably without running continuously. Wi-Fi enabled units (Aprilaire E100 with the Wi-Fi module or AlorAir units with app control) let the homeowner monitor RH remotely and get alerts if humidity climbs above target — worth it for homeowners who travel.
Unit selection on Matthews jobs is driven by crawl cubic footage and moisture load. Aprilaire E070 (70 pints per day at AHAM conditions) is my default for tight sealed 1,500 to 2,200 SF crawls. Santa Fe Compact 70 (also 70 pints per day) is the alternate — very similar performance, slightly different form factor, easier to service in some placements. Both are horizontal-configuration units designed for crawlspace duty, both have MERV-13 filtration, both have discharge humidistats built in.
Larger jobs go to Aprilaire E100 (100 pints per day) or Santa Fe Ultra98 (98 pints per day) for 2,200 to 3,200 SF crawl footprints. AlorAir Sentinel HDi90 (90 pints per day) is a value alternate with WiFi built in — I have installed dozens without issues but the warranty support is not as strong as Aprilaire or Santa Fe. For very large crawls above 3,500 SF (rare in Matthews but occasionally we get one on the Weddington-adjacent subdivisions), we go to the Aprilaire E130 (130 pints per day) or spec two smaller units in parallel to handle the volume.
Electrical is a dedicated 20-amp circuit on 12 AWG copper wire, GFCI-protected outlet at the unit, mechanical disconnect within sight of the unit. Runs from the panel to the crawl are usually 25 to 50 feet on a Matthews split-level. Electrical permit filed through Mecklenburg CityInspect or Union County office in Monroe depending on jurisdiction. Inspection is a walk-through with the AHJ inspector.
Condensate line is 3/4-inch schedule 40 PVC pitched at 1/8 inch per foot to a discharge point outside the foundation. Sealed through the foundation wall with SikaFlex-1a polyurethane sealant to prevent air leakage around the penetration. Discharge point is at least 3 feet from the foundation on soil sloped away, or into an existing gravel drain area, or through a condensate pump (Little Giant VCMA-20ULS is our workhorse) when gravity drain is not possible.
Filter access is critical on Matthews low-clearance crawls. On the Aprilaire E070 the MERV-13 filter is accessed from the top of the unit which requires enough clearance above the unit to slide the filter out. On the Santa Fe Compact 70 the filter is a side-access configuration. On any Matthews job I confirm filter access is possible before finalizing placement — a dehumidifier that cannot be serviced without disassembling the crawl envelope is a dehumidifier that will not get serviced.
Yes — Matthews is a regular dehumidifier route. Free on-site inspection anywhere in Matthews, fixed written quote before we touch anything.
Matthews dehumidifier work is dominated by finishing 90s-2000s builder partial encapsulations off Sardis Rd and out to the Weddington Chase side where the builder installed 6-mil plastic and sealed vents but skipped the dehumidifier entirely, plus retrofit installs into the low-clearance 1970s-80s split-level stock where unit placement is constrained by 22-inch working room.
28104, 28105. All Mecklenburg County addresses covered.
Yes, and about a third of the Matthews jobs I do in a year are exactly this scope. A sealed crawl without a dehumidifier is a moisture trap — the vents are closed so moist air cannot escape the way it could through a vented crawl, but there is no mechanical drying, so any moisture that gets into the envelope from the ground, from HVAC leaks, from the block walls wicking, or from stack effect stays in the crawl and drives humidity up over time. On the Sardis Rd subdivisions I see partial builder encapsulations running 75 to 85 percent RH every summer. Adding a properly sized dehumidifier drops them to 50 to 55 percent within a few days and holds them there through peak summer. Also worth noting: some HVAC warranties now void if crawl humidity exceeds 60 percent RH — the dehumidifier is what keeps that warranty enforceable.
Placement is constrained but there is almost always a workable spot. On a 22-inch clearance crawl the Aprilaire E070 or a horizontal-configuration Santa Fe fits under the joists with enough working room to service the filter. Best placement is usually near the crawl entry hatch so filter changes and unit inspection are easy, and near an exterior wall so the condensate discharge line has a short run to daylight. I map the exact spot on the inspection before writing the scope so you know what to expect. On the tightest Matthews crawls we sometimes place the unit in a slightly deeper section (a former basement stub, a mechanical alcove, or the section under a garage floor that has more clearance) to get around the low-clearance constraint.
Depends on how hard it runs, which depends on how well the envelope is sealed and how humid the outside air is. On a well-sealed Matthews encapsulation the Aprilaire E070 typically runs 4 to 6 hours per day in peak summer humidity and less in spring and fall. Annual electric cost is modest compared to the HVAC savings from not having your AC dehumidifying the crawl through stack effect. On a poorly sealed crawl or one where the vapor barrier is not properly terminated the unit runs longer and consumes more electricity — which is why we insist on doing the sealing work right if we are also installing a dehumidifier.
Compressor life is typically 8 to 12 years on Aprilaire and Santa Fe units with regular filter changes (annual minimum, twice a year is better). AlorAir is closer to 6 to 10 years on the compressor. When the compressor fails it is usually not economical to repair — replacement of the whole unit is the standard path. Failure mode on the older 1990s dehumidifiers I sometimes replace on Matthews jobs is either compressor failure or the humidistat sensor drifting so the unit no longer knows when to cycle. Modern units have solid-state sensors that hold calibration better.
Free on-site Matthews inspection. Fixed written quote. Call (980) 227-1769 or book below.