{
  "version": "2026-09-13",
  "urgency": {
    "safety": { "rank": 3, "title": "Safety first — act now", "text": "Stop using the equipment involved and follow the steps below before anything else." },
    "soon": { "rank": 2, "title": "Book an inspection soon", "text": "This problem gets worse or costs more the longer it runs. Plan a professional check within the next few weeks." },
    "monitor": { "rank": 1, "title": "Try the home checks first", "text": "Start with the checks below. Book a professional if they don't solve it." }
  },
  "services": {
    "residential": { "name": "Residential air duct cleaning", "url": "/air-duct-cleaning/residential/" },
    "dirty": { "name": "Dirty and dusty air duct cleaning", "url": "/air-duct-cleaning/dirty-dusty-ducts/" },
    "post_construction": { "name": "Post-construction air duct cleaning", "url": "/air-duct-cleaning/post-construction/" },
    "new_home": { "name": "New home air duct cleaning", "url": "/air-duct-cleaning/new-home/" },
    "mold": { "name": "Air duct mold remediation", "url": "/indoor-air-quality/mold-remediation/" },
    "iaq": { "name": "Indoor air quality services", "url": "/indoor-air-quality/" },
    "allergies": { "name": "Air duct cleaning for allergies", "url": "/indoor-air-quality/allergies/" },
    "pet_hair": { "name": "Pet hair air duct cleaning", "url": "/indoor-air-quality/pet-hair/" },
    "inspection": { "name": "Air duct inspection", "url": "/duct-inspection-repair/inspection/" },
    "leak_detection": { "name": "Air duct leak detection", "url": "/duct-inspection-repair/leak-detection/" },
    "sealing": { "name": "Air duct sealing", "url": "/duct-inspection-repair/sealing/" },
    "repair": { "name": "Air duct repair", "url": "/duct-inspection-repair/repair/" },
    "dryer_clean": { "name": "Dryer vent cleaning", "url": "/vent-exhaust/dryer-vent-cleaning/" },
    "dryer_repair": { "name": "Dryer vent repair", "url": "/vent-exhaust/dryer-vent-repair/" },
    "bird_nest": { "name": "Bird nest and lint removal", "url": "/vent-exhaust/bird-nest-lint-removal/" }
  },
  "causes": {
    "filter": {
      "title": "A clogged, loose or wrong-size filter",
      "explain": "Air takes the easiest path. A filter that doesn't fill its slot lets dust slip around it, and a clogged filter starves the system of airflow.",
      "checks": ["Pull the filter and hold it up to a light. Replace it if you can't see light through it.", "Match the size printed on the filter frame to the slot, and look for gaps around the edges.", "Use the highest-efficiency filter your system's manufacturer allows."],
      "service": "inspection", "urgency": "monitor",
      "source": "U.S. EPA, Should You Have the Air Ducts in Your Home Cleaned?"
    },
    "return_leak": {
      "title": "Leaky return ducts pulling in dust",
      "explain": "Gaps in return ducts suck in air from attics, crawl spaces and wall cavities. That air carries insulation fibers and dust, and some of it never passes through the filter.",
      "checks": ["Look at return duct joints in the attic, basement or crawl space for gaps, peeling tape or dark dust streaks.", "With the fan running, feel for air being pulled in around the return panel at the air handler."],
      "service": "sealing", "urgency": "soon",
      "source": "ENERGY STAR, Duct Sealing"
    },
    "duct_debris": {
      "title": "Heavy dust and debris inside the ducts",
      "explain": "Ducts clogged with enough debris to release it through the supply registers are one of the EPA's three reasons to clean a home's ductwork.",
      "checks": ["Remove a supply register and shine a flashlight into the duct opening.", "Watch whether dust puffs out of the registers when the fan starts."],
      "service": "dirty", "urgency": "soon",
      "source": "U.S. EPA, Should You Have the Air Ducts in Your Home Cleaned?"
    },
    "construction_dust": {
      "title": "Construction dust in the duct system",
      "explain": "Sawing, sanding and drywall work fill the air with fine dust that gets drawn into ducts even when the system is off. Flex duct's grooved lining holds onto it.",
      "checks": ["Look for fine white powder or sawdust in register boots and on the return grille.", "Replace the filter now and check it again after 30 days."],
      "service": "post_construction", "urgency": "soon",
      "source": "U.S. EPA Indoor airPLUS, Duct Protection During Construction"
    },
    "wet_coil": {
      "title": "A wet coil, clogged drain pan or mold near the air handler",
      "explain": "The cooling coil pulls water out of the air all summer. When the drain pan or line clogs, standing water and mold follow, and the smell rides into every room.",
      "checks": ["Look at the drain pan under the indoor coil for standing water or slime.", "Confirm the condensate line drips or drains while the air conditioner runs.", "If you see mold on the unit or ducts, turn the system off until it's inspected — the EPA warns that running it can spread spores."],
      "service": "mold", "urgency": "soon",
      "source": "U.S. EPA, A Brief Guide to Mold, Moisture and Your Home"
    },
    "humidity": {
      "title": "Indoor humidity above 60 percent",
      "explain": "The EPA recommends keeping indoor humidity below 60 percent, ideally between 30 and 50 percent. Above that, musty smells, condensation and mold growth become likely.",
      "checks": ["Measure humidity with an inexpensive meter; the EPA puts them at about $10 to $50.", "Run bathroom and kitchen exhaust fans that vent outdoors.", "Use a dehumidifier in a damp basement."],
      "service": "iaq", "urgency": "monitor",
      "source": "U.S. EPA, A Brief Guide to Mold, Moisture and Your Home"
    },
    "burnoff": {
      "title": "Dust burning off the heating equipment",
      "explain": "Dust settles on furnace parts and electric heating elements over the warm months. The first heating cycles of the season burn it off, which causes a short dusty smell.",
      "checks": ["Replace the filter before the heating season.", "Open a window and let the system run; a burn-off smell fades within the first day of use.", "If the smell stays, keeps returning or smells like hot plastic or wiring, turn the system off and call an HVAC technician."],
      "service": "inspection", "urgency": "monitor",
      "source": "Common HVAC maintenance guidance"
    },
    "electrical": {
      "title": "An overheating motor or electrical part",
      "explain": "A hot-plastic or burning-wire smell from the vents points to a blower motor, wiring or electric heat strip running too hot.",
      "checks": ["Turn the system off at the thermostat.", "Switch off the heating and cooling circuit breaker if the smell continues.", "Have a licensed HVAC technician check it before you run the system again."],
      "service": "inspection", "urgency": "safety",
      "source": "Electrical safety practice"
    },
    "gas": {
      "title": "A possible natural gas leak",
      "explain": "Gas utilities add an odorant called mercaptan so natural gas smells like sulfur or rotten eggs. Only qualified personnel can confirm whether it's a leak, so treat the smell as one.",
      "checks": ["Leave the home immediately, leaving doors and windows open if you can do it on the way out.", "Don't turn lights or appliances on or off, light a flame, or use a phone until you're safely away.", "From a safe spot, call 911, then your gas utility's emergency line. Washington Gas customers: 844-WASHGAS (927-4427), option 1."],
      "service": "inspection", "urgency": "safety",
      "source": "Washington Gas, Natural Gas Safety"
    },
    "dryer_lint": {
      "title": "Lint buildup in the dryer exhaust duct",
      "explain": "The U.S. Fire Administration reports that failure to clean was the leading factor in home clothes dryer fires from 2018 to 2020, at 31 percent. Lint that slips past the screen builds up in the duct and slows airflow.",
      "checks": ["Clean the lint screen before or after every load, as the Consumer Product Safety Commission advises.", "Go outside while the dryer runs and check that the vent flap opens.", "If the dryer or laundry area feels hot or smells like burning, stop using the dryer until the vent is cleaned."],
      "service": "dryer_clean", "urgency": "soon",
      "source": "U.S. Fire Administration; U.S. Consumer Product Safety Commission"
    },
    "dryer_route": {
      "title": "A crushed, kinked or overly long dryer duct",
      "explain": "Virginia's residential code calls for a smooth-interior metal dryer exhaust duct, 4 inches in diameter, no longer than 35 feet, with each elbow reducing the allowed length. A flattened hose behind the dryer or a long, twisting run restricts airflow even when it's clean.",
      "checks": ["Pull the dryer out and look for a flattened or kinked connector hose.", "Count the elbows between the dryer and the outside cap."],
      "service": "dryer_repair", "urgency": "soon",
      "source": "2021 Virginia Residential Code, Section M1502"
    },
    "bird_nest": {
      "title": "A nest or blockage at the outside vent",
      "explain": "Birds and rodents build in vent caps that stay open. Virginia's code requires a backdraft damper on dryer vents and prohibits screens, because lint clogs mesh.",
      "checks": ["With the dryer or fan running, check whether the outside flap opens.", "Look and listen for twigs, grass or chirping at the vent cap.", "Don't add a screen to a dryer vent; the code prohibits it."],
      "service": "bird_nest", "urgency": "soon",
      "source": "2021 Virginia Residential Code, Section M1502.3"
    },
    "duct_leaks": {
      "title": "Leaky, kinked or disconnected ducts",
      "explain": "ENERGY STAR estimates a typical house loses 20 to 30 percent of the air in its ducts to leaks, holes and poor connections. Rooms at the end of a leaky or crushed run get the least air.",
      "checks": ["Compare the airflow at the problem room's register with other rooms.", "Make sure the register damper is open and furniture isn't blocking it.", "Look for crushed flex duct or loose joints in the attic or basement."],
      "service": "leak_detection", "urgency": "soon",
      "source": "ENERGY STAR, Duct Sealing"
    },
    "vermin": {
      "title": "Rodents or insects in the ductwork",
      "explain": "Vermin in ducts are one of the EPA's three reasons to clean. Droppings and nesting material sit right in the airstream.",
      "checks": ["Note where and when you hear the sounds.", "Turn off the system fan if you find droppings near registers until the ducts are inspected.", "Find and seal the entry point before any cleaning, or the problem returns."],
      "service": "inspection", "urgency": "soon",
      "source": "U.S. EPA, Should You Have the Air Ducts in Your Home Cleaned?"
    },
    "allergens": {
      "title": "Allergens circulating past a low-grade filter",
      "explain": "Dust, dander and pollen move through the house with every fan cycle. The EPA has never found that duct cleaning prevents health problems, so filtration and humidity come first.",
      "checks": ["Use the highest-efficiency filter your system allows, and check that it fits without gaps.", "Keep indoor humidity between 30 and 50 percent.", "Change the filter on schedule, more often during shedding or pollen seasons."],
      "service": "allergies", "urgency": "monitor",
      "source": "U.S. EPA"
    },
    "pet_dander": {
      "title": "Pet hair and dander packed in return ducts",
      "explain": "Pet hair collects on return grilles, filters and the first few feet of return ducts. NADCA recommends that pet owners have ducts cleaned on a regular basis.",
      "checks": ["Vacuum the return grilles and change filters more often during shedding seasons.", "Remove a return grille and look for hair mats inside the duct."],
      "service": "pet_hair", "urgency": "monitor",
      "source": "NADCA, Reduce Air Pollution with Air Duct Cleaning (2017)"
    },
    "sweating": {
      "title": "Condensation on uninsulated or leaky ducts",
      "explain": "Cold air conditioning ducts running through humid attics, crawl spaces and basements collect condensation, the same way a cold glass sweats. The EPA calls condensation a major moisture source in duct systems.",
      "checks": ["While the AC runs, feel ducts in the attic, crawl space or basement for moisture.", "Look for torn, missing or wet duct insulation.", "Replace any duct insulation that has gotten wet or moldy; the EPA says it can't be cleaned."],
      "service": "repair", "urgency": "soon",
      "source": "U.S. EPA; ENERGY STAR, Duct Sealing"
    },
    "noisy": {
      "title": "Airflow noise from closed registers or loose ductwork",
      "explain": "Whistling usually means air squeezing through a partly closed register or a gap. Rattling and banging point to loose duct sections or metal flexing as the fan starts and stops.",
      "checks": ["Open every supply register fully and clear anything blocking returns.", "Listen near the air handler and at visible duct joints while the fan starts."],
      "service": "inspection", "urgency": "monitor",
      "source": "Common HVAC maintenance guidance"
    },
    "after_cleaning": {
      "title": "Dust released during a poorly contained duct cleaning",
      "explain": "The EPA warns that a duct cleaning done without proper vacuum collection can release more dust into the home than it removes.",
      "checks": ["Replace the filter now.", "Ask the company whether the whole system stayed under negative pressure during the job.", "Ask for before-and-after camera footage of the same duct runs."],
      "service": "inspection", "urgency": "soon",
      "source": "U.S. EPA, Should You Have the Air Ducts in Your Home Cleaned?"
    }
  },
  "symptoms": [
    {
      "id": "dust", "guide": "/problems/dust-blowing-from-vents/", "label": "Dust blowing from vents", "desc": "Visible dust, puffs at startup, or furniture getting dusty fast", "icon": "dust", "color": "#4fb3d9",
      "questions": [
        { "id": "when", "text": "When do you notice the dust?", "options": [
          { "id": "startup", "label": "Mostly when the system starts", "scores": { "duct_debris": 2, "filter": 1 } },
          { "id": "always", "label": "All the time", "scores": { "filter": 2, "return_leak": 2 } },
          { "id": "reno", "label": "Since a renovation or move-in", "scores": { "construction_dust": 3 } }
        ]},
        { "id": "filter", "text": "When was the filter last changed?", "options": [
          { "id": "recent", "label": "Within the last 3 months", "scores": { "return_leak": 1, "duct_debris": 1 } },
          { "id": "old", "label": "More than 3 months ago, or not sure", "scores": { "filter": 3 } }
        ]},
        { "id": "location", "text": "Do any ducts run through an attic, crawl space or garage?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "return_leak": 2 } },
          { "id": "no", "label": "No, or not sure", "scores": { "duct_debris": 1 } }
        ]}
      ]
    },
    {
      "id": "musty", "guide": "/problems/musty-smell-from-vents/", "label": "Musty or moldy smell", "desc": "A damp, stale smell from the vents", "icon": "drop", "color": "#4ade80",
      "questions": [
        { "id": "when", "text": "When is the smell strongest?", "options": [
          { "id": "ac", "label": "When the air conditioning runs", "scores": { "wet_coil": 3 } },
          { "id": "always", "label": "All year round", "scores": { "humidity": 2, "wet_coil": 1 } },
          { "id": "leak", "label": "Since a water leak or flood", "scores": { "wet_coil": 3 }, "urgency": "soon" }
        ]},
        { "id": "visible", "text": "Can you see water, slime or mold near the indoor unit or vents?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "wet_coil": 3 }, "urgency": "soon" },
          { "id": "no", "label": "No, or I can't reach it", "scores": { "humidity": 1 } }
        ]},
        { "id": "humid", "text": "Do windows fog up or does the house feel damp?", "options": [
          { "id": "yes", "label": "Yes, often", "scores": { "humidity": 3 } },
          { "id": "no", "label": "No", "scores": { "wet_coil": 1 } }
        ]}
      ]
    },
    {
      "id": "burning", "guide": "/problems/burning-smell-from-vents/", "label": "Burning or strange smell", "desc": "Dusty burning, hot plastic, or rotten eggs", "icon": "flame", "color": "#f87171",
      "questions": [
        { "id": "type", "text": "What does it smell like?", "options": [
          { "id": "egg", "label": "Rotten eggs or sulfur", "scores": { "gas": 10 }, "urgency": "safety", "stop": true },
          { "id": "plastic", "label": "Hot plastic or burning wires", "scores": { "electrical": 5 }, "urgency": "safety" },
          { "id": "dusty", "label": "Dusty burning, when the heat first comes on", "scores": { "burnoff": 4 } },
          { "id": "laundry", "label": "Burning near the laundry room", "scores": { "dryer_lint": 5 }, "urgency": "safety" }
        ]},
        { "id": "duration", "text": "Does the smell fade or keep coming back?", "options": [
          { "id": "fades", "label": "It fades within a day", "scores": { "burnoff": 2 } },
          { "id": "returns", "label": "It keeps coming back or gets stronger", "scores": { "electrical": 3 }, "urgency": "safety" }
        ]}
      ]
    },
    {
      "id": "dryer", "guide": "/problems/dryer-takes-too-long/", "label": "Dryer takes too long", "desc": "Clothes need extra cycles, or the laundry room gets hot", "icon": "dryer", "color": "#fb923c",
      "questions": [
        { "id": "flap", "text": "With the dryer running, what does the outside vent flap do?", "options": [
          { "id": "opens", "label": "Opens fully", "scores": { "dryer_route": 1, "dryer_lint": 1 } },
          { "id": "barely", "label": "Barely opens, or stays shut", "scores": { "dryer_lint": 2, "bird_nest": 2 } },
          { "id": "unknown", "label": "I can't find it, or it's on the roof", "scores": { "dryer_lint": 2 } }
        ]},
        { "id": "heat", "text": "Does the dryer or laundry room get unusually hot, or smell like burning?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "dryer_lint": 3 }, "urgency": "safety" },
          { "id": "no", "label": "No", "scores": { "dryer_route": 1 } }
        ]},
        { "id": "last", "text": "When was the dryer vent last cleaned?", "options": [
          { "id": "year", "label": "Within the last year", "scores": { "dryer_route": 2 } },
          { "id": "long", "label": "More than a year ago, or never", "scores": { "dryer_lint": 2 } }
        ]}
      ]
    },
    {
      "id": "comfort", "guide": "/problems/uneven-room-temperatures/", "label": "Rooms too hot or too cold", "desc": "Uneven temperatures or weak airflow in some rooms", "icon": "thermo", "color": "#818cf8",
      "questions": [
        { "id": "where", "text": "Which describes the problem best?", "options": [
          { "id": "some", "label": "One or two rooms", "scores": { "duct_leaks": 3 } },
          { "id": "upstairs", "label": "The whole upper floor", "scores": { "duct_leaks": 2, "filter": 1 } },
          { "id": "house", "label": "The whole house", "scores": { "filter": 3 } }
        ]},
        { "id": "airflow", "text": "How does the airflow feel at a register in the problem room?", "options": [
          { "id": "weak", "label": "Weak or barely there", "scores": { "duct_leaks": 3 } },
          { "id": "normal", "label": "About the same as other rooms", "scores": { "filter": 1 } }
        ]},
        { "id": "location", "text": "Do ducts run through an attic, crawl space or garage?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "duct_leaks": 2 } },
          { "id": "no", "label": "No, or not sure", "scores": {} }
        ]}
      ]
    },
    {
      "id": "allergy", "label": "Allergies worse indoors", "desc": "Sneezing or stuffiness that eases outside", "icon": "leaf", "color": "#fbbf24",
      "questions": [
        { "id": "pets", "text": "Do you have pets that shed?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "pet_dander": 3 } },
          { "id": "no", "label": "No", "scores": { "allergens": 1 } }
        ]},
        { "id": "filtertype", "text": "What kind of filter does the system use?", "options": [
          { "id": "basic", "label": "Thin fiberglass, or not sure", "scores": { "allergens": 3 } },
          { "id": "pleated", "label": "Pleated, higher-efficiency", "scores": { "duct_debris": 1 } }
        ]},
        { "id": "visible", "text": "Do you see dust come out of the vents when the fan starts?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "duct_debris": 3 } },
          { "id": "no", "label": "No", "scores": { "allergens": 1 } }
        ]}
      ]
    },
    {
      "id": "critters", "label": "Noises or animals in vents", "desc": "Scratching, chirping, droppings, whistling or rattles", "icon": "sound", "color": "#c084fc",
      "questions": [
        { "id": "sound", "text": "What do you hear or see?", "options": [
          { "id": "scratch", "label": "Scratching or scurrying inside ducts", "scores": { "vermin": 3 } },
          { "id": "chirp", "label": "Chirping or nesting at an outside vent", "scores": { "bird_nest": 4 } },
          { "id": "whistle", "label": "Whistling, rattling or banging", "scores": { "noisy": 3, "duct_leaks": 1 } }
        ]},
        { "id": "droppings", "text": "Have you found droppings or nesting material near registers?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "vermin": 3 }, "urgency": "soon" },
          { "id": "no", "label": "No", "scores": {} }
        ]}
      ]
    },
    {
      "id": "moisture", "label": "Water or sweating ducts", "desc": "Drips from registers, wet ducts or water near the unit", "icon": "wave", "color": "#38bdf8",
      "questions": [
        { "id": "where", "text": "Where do you see the water?", "options": [
          { "id": "register", "label": "Dripping from a ceiling register", "scores": { "sweating": 3, "wet_coil": 1 } },
          { "id": "unit", "label": "Around the indoor unit", "scores": { "wet_coil": 4 }, "urgency": "soon" },
          { "id": "ducts", "label": "On ducts in the attic, crawl space or basement", "scores": { "sweating": 4 } }
        ]},
        { "id": "season", "text": "When does it happen?", "options": [
          { "id": "summer", "label": "When the air conditioning runs", "scores": { "sweating": 2, "wet_coil": 1 } },
          { "id": "anytime", "label": "Any time of year", "scores": { "humidity": 2 } }
        ]}
      ]
    },
    {
      "id": "newdust", "guide": "/problems/new-house-dusty/", "label": "Dust after construction or cleaning", "desc": "New home, renovation, or dust right after a duct cleaning", "icon": "hammer", "color": "#a3e635",
      "questions": [
        { "id": "situation", "text": "Which fits your situation?", "options": [
          { "id": "newbuild", "label": "Newly built home", "scores": { "construction_dust": 4 } },
          { "id": "reno", "label": "Renovation done with the system running", "scores": { "construction_dust": 4 } },
          { "id": "cleaned", "label": "Right after a duct cleaning", "scores": { "after_cleaning": 4 } }
        ]},
        { "id": "filtergray", "text": "Did a new filter turn gray within a month?", "options": [
          { "id": "yes", "label": "Yes", "scores": { "construction_dust": 2, "after_cleaning": 1 } },
          { "id": "no", "label": "No, or not sure", "scores": { "filter": 1 } }
        ]}
      ]
    }
  ],
  "home": {
    "home_type": { "label": "Type of home", "options": { "single": "Single-family house", "townhome": "Townhome", "condo": "Condo or apartment" } },
    "year_built": { "label": "When was it built?", "options": { "pre1980": "Before 1980", "y1980": "1980–1999", "y2000": "2000–2009", "y2010": "2010 or later", "unknown": "Not sure" } },
    "tenure": { "label": "Do you own or rent?", "options": { "own": "Own", "rent": "Rent" } }
  },
  "context_notes": [
    { "when": { "year_built": ["pre1980"] }, "text": "Your home was built before 1980. Older heating equipment can contain asbestos insulation, and the EPA advises checking system materials for asbestos before any duct cleaning." },
    { "when": { "tenure": ["rent"] }, "text": "You rent. Under Code of Virginia § 55.1-1220, landlords must keep heating, ventilating and air-conditioning systems in good and safe working order. Send your landlord a written request before hiring anyone." },
    { "when": { "home_type": ["townhome", "condo"], "symptom": ["dryer"] }, "text": "Townhome and condo dryer vents often run to the roof or a high wall. Choose a company that cleans the full run to the outside cap, and check HOA rules for roof access." },
    { "when": { "year_built": ["y2010"], "symptom": ["dust", "newdust", "allergy"] }, "text": "Your home is newer. In homes built within the last decade, construction debris is a common source of duct dust, so check the register boots before paying for a full cleaning." }
  ]
}