[{"data":1,"prerenderedAt":141},["ShallowReactive",2],{"guide-basement-dehumidifier-long-island-queens-en-US":3},{"guide":4,"related":121},{"title":5,"seoTitle":6,"description":7,"summary":8,"sections":9,"faq":80,"date":93,"service":94,"order":95,"sources":96,"slug":119,"locale":120},"Basement humidity on Long Island and in Queens and how to dehumidify it properly","Basement Dehumidifiers for Long Island and Queens","Why Long Island and Queens basements turn damp and musty in summer, the right humidity target, dehumidifier sizing after the 2019 rating change, and drainage.","Most musty basements on Long Island and in Queens are wettest in summer, when warm, humid outdoor air reaches cool foundation walls and slabs. Keep basement humidity below 60 percent, ideally about 45 to 50 percent in summer, with a correctly sized dehumidifier that drains continuously. Opening basement windows in humid weather adds moisture rather than removing it. Any liquid water must be stopped first, because a dehumidifier is not waterproofing.",[10,15,19,30,34,60,70,75],{"heading":11,"paragraphs":12},"Why basements are wettest in summer",[13,14],"Basement walls and floor slabs stay close to ground temperature all year, which in summer is much cooler than the outdoor air. When warm, humid air reaches those surfaces, its relative humidity rises sharply, and wherever the surface is colder than the air's dew point, water condenses. This is the same physics that fogs windows in winter, reversed by season.","For the same reason, airing out a basement with open windows on a humid July day adds water instead of removing it. EPA guidance is direct on this point: ventilate when outdoor air is cold and dry, and dehumidify when it is warm and humid. Running a basement fan or leaving a bulkhead door open in summer has the same effect.",{"heading":16,"paragraphs":17},"The right humidity target for a basement",[18],"EPA recommends keeping indoor humidity below 60 percent, ideally between 30 and 50 percent. Building Science Corporation notes that mold is controlled by keeping the air against a surface below about 70 percent RH. Because the air next to a cool wall is always more humid than the room average, a basement reading of 60 percent can mean 70 percent or more at the wall. A practical summer target for a basement is therefore about 45 to 50 percent, measured with a digital hygrometer placed away from the dehumidifier.",{"heading":20,"paragraphs":21,"list":23},"Stop liquid water before you dehumidify",[22],"A dehumidifier removes moisture from the air. It cannot keep up with water entering through walls and floors, and it does not repair the cause. In low-lying south shore neighborhoods and in homes that flooded during Hurricane Sandy in 2012, the water table and drainage deserve particular attention. Check these sources first.",[24,25,26,27,28,29],"Gutters and downspouts that discharge next to the foundation instead of several feet away.","Soil and paving that slope toward the house rather than away from it.","Window wells without covers or drains, and basement stairwell drains that are clogged.","Foundation cracks, damp lines at the base of walls, and white mineral deposits (efflorescence), which show that water is moving through the masonry.","Sump pumps that fail, discharge too close to the house, or have no backup.","Plumbing leaks, a disconnected dryer vent, or a laundry area without exhaust.",{"heading":31,"paragraphs":32},"Sweating pipes and other cold surfaces",[33],"Cold water pipes, water meters, ducts carrying air-conditioned air and the floor slab under carpet are the surfaces most likely to sweat. EPA describes two remedies: raise the surface temperature with insulation, or lower the humidity of the air. Closed-cell foam pipe insulation on cold water lines and sealed, insulated supply ducts stop dripping that otherwise stains ceilings and wets stored items. Lowering humidity with a dehumidifier protects the surfaces that cannot be insulated.",{"heading":35,"paragraphs":36,"table":38,"after":58},"Sizing a portable dehumidifier after the 2019 rating change",[37],"Since 2019, the Department of Energy test for portable dehumidifiers has been run at 65 °F instead of 80 °F, to reflect basement conditions. The same machine now carries a lower pint rating than it did under the old test. Reviews and sizing charts written before the change therefore describe capacity in different terms from current labels.",{"caption":39,"head":40,"rows":43},"Approximate correspondence between old and new portable dehumidifier ratings (ENERGY STAR)",[41,42],"Old rating, through 2019 (pints per day)","Approximate new rating (pints per day)",[44,47,50,52,55],[45,46],"30","20",[48,49],"40","25",[51,45],"50",[53,54],"60","35",[56,57],"70","40 to 45",[59],"Choose an ENERGY STAR model sized for the area and dampness of the space, set it to 45 to 50 percent, and connect it to a continuous drain. A unit that relies on its bucket fills within hours in a damp basement and stops running. Place it where air can circulate, not in a closed room, and check its low-temperature rating, since cool basements reduce the output of many portable units.",{"heading":61,"paragraphs":62,"list":64},"When a whole-house dehumidifier makes sense",[63],"A ducted whole-house dehumidifier is a permanently installed unit that treats the basement, or the basement and the rest of the house, through ductwork, with its own drain. It is usually quieter and more efficient than running one or more portable units around the clock.",[65,66,67,68,69],"Large, open or finished basements where a single portable unit cannot keep humidity at 50 percent.","Basements that are used as living space and need quiet, automatic operation.","Houses where central air conditioning short-cycles and leaves the house cool but clammy in spring and early fall.","Basements with no cooling load, which receive almost no dehumidification from the air conditioning upstairs.","Spaces where the drain can be routed to a floor drain, laundry standpipe or condensate pump, which is the core of a proper installation.",{"heading":71,"paragraphs":72},"Finished basements, crawl spaces and radon",[73,74],"Many finished basements in Queens, Brooklyn and Nassau trap moisture because of their materials. Fiberglass batts pressed against foundation walls, vinyl wallpaper on exterior walls, carpet laid directly on the slab and wood framing in contact with concrete all hold moisture and support mold. A better assembly uses rigid foam board (XPS or EPS) against the foundation before framing, keeps framing off the slab, and uses flooring that tolerates occasional dampness. Converting a basement into a separate apartment raises legal and zoning questions that are outside the scope of this guide.","Crawl spaces follow the same rule. A vented crawl space admits humid summer air, while a closed crawl space with a sealed vapor barrier can be dehumidified or conditioned. On the EPA Map of Radon Zones, Nassau, Suffolk and the five boroughs are Zone 3, the lowest predicted potential, but EPA still recommends testing every home. If mold covers a large area, we recommend a qualified mold assessment and remediation professional before rebuilding.",{"heading":76,"paragraphs":77},"Winter conditions and how we can help",[78,79],"In winter the same basement is often dry, and the dehumidifier's humidistat will keep it off. If a basement stays humid in January, look for a water source such as a leak, a wet wall or an unvented dryer, because dry winter air should not produce that reading.","We start by finding the moisture source, measuring the space and checking the drainage options. We then recommend the right combination of pipe insulation, portable or whole-house dehumidification and drainage, and install it with our licensed HVAC partner. Where the cause is water entry, we address the gutters, grading or foundation work first, so the dehumidifier does not have to compensate for it.",[81,84,87,90],{"q":82,"a":83},"What humidity should a basement be kept at?","Below 60 percent at all times, and ideally about 45 to 50 percent in summer. EPA recommends 30 to 50 percent indoors, and keeping the room in that range keeps the air against cool walls and slabs below the level at which mold grows.",{"q":85,"a":86},"Should I open basement windows in summer?","Not on warm, humid days. Humid outdoor air brings in more moisture, which condenses on the cool walls and floor. Ventilate when the outdoor air is cool and dry, and run a dehumidifier when it is warm and humid.",{"q":88,"a":89},"Is a 50 pint dehumidifier today the same as an old 50 pint model?","No. Since 2019 dehumidifiers are tested at 65 °F instead of 80 °F, so ratings are lower. According to ENERGY STAR, an old 70 pint unit corresponds to about 40 to 45 pints today, and an old 50 pint unit to about 30 pints.",{"q":91,"a":92},"Will a dehumidifier fix a wet basement?","Only when the moisture comes from humid air. If water enters through walls, cracks or the floor, the gutters, grading, drainage or foundation must be corrected first. The dehumidifier then controls the remaining humidity.","2026-10-25","hvac",82,[97,101,105,108,112,116],{"title":98,"url":99,"publisher":100},"Dehumidifier Testing and Capacity","https:\u002F\u002Fwww.energystar.gov\u002Fproducts\u002Fdehumidifier_testing_and_capacity","ENERGY STAR",{"title":102,"url":103,"publisher":104},"A Brief Guide to Mold, Moisture and Your Home","https:\u002F\u002Fwww.epa.gov\u002Fmold\u002Fbrief-guide-mold-moisture-and-your-home","U.S. Environmental Protection Agency",{"title":106,"url":107,"publisher":104},"Interactive Mold House Tour","https:\u002F\u002Fwww.epa.gov\u002Fmold\u002Finteractive-mold-house-tour",{"title":109,"url":110,"publisher":111},"RR-0203: Relative Humidity","https:\u002F\u002Fbuildingscience.com\u002Fdocuments\u002Freports\u002Frr-0203-relative-humidity\u002Fview","Building Science Corporation",{"title":113,"url":114,"publisher":115},"The Confusing World of Dehumidifier Capacity","https:\u002F\u002Fwww.greenbuildingadvisor.com\u002Farticle\u002Fthe-confusing-world-of-dehumidifier-capacity","Green Building Advisor",{"title":117,"url":118,"publisher":104},"New York - EPA Map of Radon Zones","https:\u002F\u002Fwww.epa.gov\u002Fsites\u002Fdefault\u002Ffiles\u002F2014-08\u002Fdocuments\u002Fnew_york.pdf","basement-dehumidifier-long-island-queens","en-US",[122,128,132,137],{"slug":123,"title":124,"description":125,"service":126,"date":127},"nyc-renovation-permits","NYC permits for renovation, electrical and plumbing work","Which renovation, electrical and plumbing jobs need a NYC Department of Buildings permit, who files it, and what changes on Long Island.","electrical","2026-10-24",{"slug":129,"title":130,"description":131,"service":126,"date":127},"electrical-panel-upgrade","Electrical panel and service upgrades for NYC and Long Island homes","When an older NYC or Long Island home needs a new panel or a bigger electrical service, what the work involves, and how long it takes.",{"slug":133,"title":134,"description":135,"service":136,"date":93},"ev-charging-without-service-upgrade","EV charging without an expensive service upgrade","Load sharing, CT-clamp load management, dryer-outlet sharing and right-sized chargers: ways to add EV charging in NYC and Long Island without upgrading your electrical service.","ev-charging",{"slug":138,"title":139,"description":140,"service":136,"date":127},"ev-charger-installation","Installing a home EV charger in NYC or Long Island","Level 1 vs Level 2 charging, panel capacity, permits, Tesla Powershare, and what to know for houses and buildings in NYC and Long Island.",1792924280128]