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 Mobile ViewAIR CONDITIONING & HEAT PUMP SYSTEMS A/C - HEAT PUMP CONTROLS & SWITCHES A/C DATA TAGS A/C - HEAT PUMP CRITICAL DEFECTS A/C DIAGNOSTIC FAQs A/C REFRIGERANTS A/C TYPES, ENERGY SOURCES AGE of AIR CONDITIONERS & HEAT PUMPS AGE of HEATERS, BOILERS, FURNACES AGE of WATER HEATERS AIR CONDITIONER BTU CHART AIR CONDITIONER COMPONENT PARTS AIR CONDITIONER TYPES, ENERGY SOURCES AIR CONDITIONER NOT WORKING AIR FILTERS for HVAC SYSTEMS AIR HANDLER / BLOWER UNITS ANIMAL ALLERGENS / PET DANDER ANIMAL ENTRY POINTS in buildings ANIMAL ODORS IN buildings APPLIANCE EFFICIENCY RATINGS ASBESTOS IDENTIFICATION IN buildings BACKUP HEAT for HEAT PUMPS BLOWER DOORS & AIR INFILTRATION BLOWER FAN CONTINUOUS OPERATION BLOWER FAN OPERATION & TESTING BOOKSTORE - Air Conditioning "How To" Books CAPACITORS for HARD STARTING MOTORS CAPILLARY TUBES CLEANING & Legionella BACTERIA CHINESE DRYWALL HAZARDS COMBUSTION GASES & PARTICLE HAZARDS COMPRESSOR & CONDENSING COIL, A/C CONDENSATE HANDLING, A/C CLEANING & Legionella BACTERIA DUCT SYSTEM & DUCT DEFECTS AIR FILTERS for HVAC SYSTEMS ALLOY SYSTEMS FLEXDUCT ASBESTOS HVAC DUCTS ASBESTOS PAPER on DUCTWORK ASBESTOS TRANSITE DUCTWORK BALANCING AIR DUCT FLOW DUCT & AIR HANDLER ODORS DUCT DAMAGE, MECHANICAL DUCT INSULATION - Asbestos Paper DUCT ROUTING & SUPPORT DUST CONTAMINATION FROM HVAC? FIBERGLASS DUCT, RIGID CONSTRUCTION FIBERGLASS HVAC DUCTS FIRE DAMPERS in DUCTWORK FLOOD DAMAGE in DUCT WORK GOODMAN GRAY FLEXDUCT INCREASING RETURN AIR LEAKY DUCT CONNECTIONS LOCATION OF REGISTERS & DUCTS MOLD in AIR HANDLERS & DUCT WORK NOISES in DUCT SYSTEM ODORS in AIR HANDLERS & DUCT WORK OWENS CORNING FLEXDUCT OWL FLEXDUCT RETURN AIR REGISTERS & DUCTS SOUNDPROOFING for DUCTWORK SUPPLY DUCTS & REGISTERS TRANSITE PIPE AIR DUCTS UNDERSIZED RETURN DUCTS UNSAFE DUCT OPENINGS VIBRATION DAMPENERS WATER & ICE IN DUCT WORK Convection Condensate Leaks into Ductwork External Leaks into Ducts Flood-Exposed HVAC Ducts WET CORRODED DUCT WORK ZONE DAMPER CONTROLS ENERGY SAVINGS in buildings EVAPORATOR COIL or COOLING COIL EVAPORATIVE COOLING SYSTEMS EVAPORATOR COIL or COOLING COIL EXPANSION VALVES, REFRIGERANT FAN, AIR HANDLER BLOWER UNIT FAN AUTO ON Thermostat Switch FAN, COMPRESSOR/CONDENSER UNIT FAN CONVECTOR HEATERS - HYDRONIC COILS FAN LIMIT SWITCH FAN NOISES FURNACES WARM AIR HEATING SYSTEMS GASES, EXPOSURE, TESTING Carbon Dioxide - CO2 Carbon Monoxide - CO METHANE GAS SOURCES GAS MEASUREMENT TOOLS GAUGE, REFRIGERATION PRESSURE TEST HEAT LOSS (or GAIN) in buildings HEAT LOSS (or GAIN) INDICATORS HEAT LOSS R U & K VALUE CALCULATION HEAT PUMPS HEATING SMALL LOADS HOUSEWRAP AIR & VAPOR BARRIERS HUMIDITY LEVEL TARGET INDOOR AIR QUALITY IMPROVEMENT GUIDE INSPECTION CHECKLIST - OUTDOOR UNIT INSPECTION LIMITATIONS LEED GREEN BUILDING CERTIFICATION LOST COOLING CAPACITY MANUALS & PARTS GUIDES - HVAC MOTOR OVERLOAD RESET SWITCH MOLD in AIR HANDLERS & DUCT WORK MOLD INFORMATION CENTER ODORS in AIR HANDLERS & DUCT WORK OPERATING COST OPERATING DEFECTS OPERATING TEMPERATURES NOISY AIR CONDITIONER / HEAT PUMP NOISE / SOUND DIAGNOSIS & CURE PORTABLE ROOM AIR CONDITIONERS PRESSURE READINGS, REFRIGERANT REPAIR GUIDE, AIR CONDITIONERS / HEAT PUMPS REPAIR & DIAGNOSTIC FAQs for A/C REFRIGERANTS RETROFIT SIZING for A/C or HEAT PUMPS SEER RATINGS & OTHER DEFINITIONS SOLAR ENERGY SYSTEMS SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS SWAMP COOLERS SYSTEM OPERATION THERMOSTATS, HEATING / COOLING THERMOSTATIC EXPANSION VALVES WATER COOLED AIR CONDITIONERS More Information |
This chapter of "How to Inspect the Central Air Conditioning or Cooling System" describes Wet or Corroded Heating & Cooling Ducts: Cause, Health Concerns,& Repairs to correct this condition. Rusty metal ducts or corroded HVAC ducts are an indicator of improper and possibly unhealthy conditions in the building as they are almost always associated with unwanted moisture in the duct system. Unwanted moisture in cooling ducts in particular, is an invitation to mold, bacterial, or other pathogens in the duct system and thus in the building air. Readers should also see WATER & ICE IN DUCT WORK and see FROST BUILD-UP on AIR CONDITIONER COILS where we describe build-up of ice on the cooling coil in air conditioning air handler units. Also see TRANSITE PIPE AIR DUCTS where we describe flooding of HVAC ductwork in slabs. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. This chapter continues with a discussion of corroded metal ducts and registers and associated health concerns. We point out and include photographs of locations where you can spot unwanted HVAC or cooling system moisture and rust, cite some related health concerns, and discuss ways to avoid duct corrosion or rust. We also offer advice on what to do about rusty ductwork. The master document, of which this is a chapter, describes the inspection of residential air conditioning systems (A/C systems) to inform home buyers, owners, and home inspectors of common cooling system defects. CORRODED DUCT WORK - Corroded Air Conditioning Duct Work
The photo at page top shows a very rusty air conditioning ductwork register, and a careful look into that system of metal duct work, found additional heavy rust in the duct system along with lots of debris. The photographs shown just above are of a less obviously rusty duct system and the rust stains on the vinyl floor suggest that the water in this duct system came from the floor level. Are Rusty, Dirty Air Conditioning Ducts a Health Concern?Not necessarily: To avoid inappropriate anxiety on the part of any readers we state up front that it is normal for some dust and debris to accumulate on the inside of heating or air conditioning ducts, and this material is not necessarily a hazard to building occupants. But when ducts have also been wet, or when ducts are constructed of materials like fiberglass insulation that have been damaged or can't be cleaned, some potential health or respiratory issues may be present, as we discuss further here. Rust flakes from rusty heating or air conditioning ducts themselves are unlikely to be much of a health hazard - these particles are pretty big, not easily airborne, and probably won't be found at high levels in indoor air except in unusual circumstances. But rust in ducts is a problem indicator, showing quite clearly that the duct system has been wet. The chief components of house dust, which will certainly collect within a duct system include fabric fibers and skin cells, often also including starch fragments and other organic debris. The combination of organic debris within a duct system and water (indicated by rusty ducts or duct registers) indicates a possible risk of mold or bacterial hazards within the air conditioning or heating system. Since blowing air through the system can pick up and distribute these hazards to occupants of the building, wet or previously-wet duct work is a potential health hazard to building occupants. The actual health hazard level from wet or previously wet air conditioning or heating ducts in a building depends on:
What To Do About Rusty HVAC Ducts, Wet or Previously Wet Fiberglass Ducts or Flex-DuctMetal ducts that have been wet but are not severely damaged can and should be professionally cleaned. Be sure that the interior of the air handler is also inspected and cleaned. Where you observe metal duct system components which are quite corroded, badly corroded materials should be replaced. This should not involve significant expense if only limited sections of readily-accessible duct work are involved. Leaks into ducts routed through inaccessible building areas or cavities, and leaks into duct work which has insulation, particularly fiberglass insulation, in its interior, (typically fiberglass board), may harbor a mold colony, leading to both significant cleanup costs and potential health concerns. Fiberglass-lined ducts or flex-ducts which have been wet should be inspected thoroughly, and sections which were wet and/or are particularly soiled should be replaced. Questions & Answers regarding this article. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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