Showing results 251 - 422 of 422
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Right: The plenum liner is well sealed to the filter-backed grille
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Right: Use mastic to air seal the return air plenum and to seal around refrigerant lines coming from the slab in the floor of the return
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Run-out duct is sealed with mastic
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Run-out ducts are installed over partition walls
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Seal all joints and seams in the metal ductwork with mastic before installing insulation
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Seal all wood framing joints surrounding the chase with sealant and lay a bead of sealant along top edge of chase framing
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Seal all wood framing joints surrounding the chase with sealant and lay a bead of sealant on top edge of chase framing
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Seal bottom layer of rigid insulation with adhesive, tape and nails
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Seal seams in fiber board ducts with out-clinching staples, UL-181A-approved tape, and mastic
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Second layer of rigid insulation is adhered with foam
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Seperate dwellings with their own seperate exhaust terminations
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Some builders create pan joists by attaching a solid sheet good to the bottom of a floor joist to create a return air pathway
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Specially designed roof trusses come with a two-foot by two-foot notch cut next to the center post providing space to install an insulated duct chase inside the home’s conditioned space but above the normal ceiling height.
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Spray foam insulation used for raised ceiling duct chase
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Spray foam insulation used for raised ceiling duct chase.
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Standard 2 in. by 4 in. stud secures duct chase - made of rigid insulation in this example
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Straps are spaced too far apart causing the straps to compress the duct under its own weight
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The AC unit has a drip pan and automatic shutoff in case the condensate drain gets clogged.
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The attic duct chase insulated and sealed to the attic floor with spray foam
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The attic is sealed and insulated along the underside of the roof deck with 5.5 inches of polyurethane spray foam, providing conditioned space for the HVAC system.
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The chase is laid out on the plans (grey highlighted areas) to aid sub-contractors to execute the design
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The drywall above the chase extends beyond adjoining top plates for a continuous air barrier
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The drywall above the dropped ceiling duct chase extends beyond adjoining top plates for a continuous air barrier
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The duct sealing spray injection system application tunnel inflates as the injection system operates
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The duct sealing spray injection system includes a blower/heater (background) and the sealant injection unit (foreground)
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The ducts are located in conditioned space in open-web joists between the floors and supported to prevent sagging.
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The grille in the photo on the left brings air into a return air plenum under an air handler platform. As shown in the infrared image on the right, the plenum is not air sealed so hot attic air is being pulled into the air handler closet.
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The heat pump water heater’s evaporator fan provides enough air movement for active ventilation of a small room when the exhaust is ducted; intake air enters passively through a wall grille
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The high-efficiency air-to-air heat pump is set in an overflow pan with an emergency shut off sensor in case the condensate tube were to clog and cause condensate to fill up the pan.
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The inner liner of the flex duct is fastened to the collar with a tension tie, the connection is sealed with mastic, then the outer layer is pulled over and sealed with mastic or foil tape (Steven Winter Associates 2013).
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The main trunk line of the ducts runs within an insulated duct chase installed in a notch designed into the roof trusses that runs the length of the home to provide supply air directly to most of the home’s ceiling registers.
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The sealed, insulated crawlspace is a clean, dry location to house the main floor heating ducts and also provides bonus storage space.
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The tape is covered with mastic to ensure an airtight seal between the duct and the fitting
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Thermal and air barriers at rim joist or new blocking prevent Infiltration of unconditioned air into the floor cavity
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These ducts were installed within the home's conditioned space in a central chaise down the main hallway.
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This “high static ducted cassette” heat pump system is similar to a traditional centrally ducted system, serving several areas of a home from one indoor unit
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This Central Fan Integrated Supply (CFIS) duct is undersized and kinked, limiting required airflow This Central Fan Integrated Supply (CFIS) duct is undersized and kinked, limiting required airflow
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This dropped soffit runs the length of the house providing a convenient place to locate one trunk duct with several very short side ducts that supply heat and cooling to most rooms of the house.
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This ducted mini-split heat pump was installed in the unvented, conditioned attic and ducted with short duct runs to several nearby rooms.
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This Habitat for Humanity builder ordered roof trusses with a 2-foot by 2-foot notch next to the center post then lined the cutout with rigid foam to form an insulated central duct chase to bring the heating and cooling ducts within the conditioned space.
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This home’s ultra-efficient ground-source heat pump provides hot water for space heating as well as domestic hot water for the 50-gallon storage tank.
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This single-zone mini-split ductless heat pump has only one indoor wall-mounted unit and one outdoor unit.
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This traditional centrally ducted heat pump heats and cools the entire home through a network of ducts.
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This typical dropped ceiling hallway chase shows a complicated air sealing scheme where chase ceiling drywall meets sidewall top plates
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This utility room houses a high-efficiency gas boiler to provide hot water for the radiant floor heating system and faucets. It also has a central air source heat pump and an energy recovery ventilator.
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To attach the flex duct to a main trunk duct or any other connection, the flex duct is pulled over the connecting collar at least 2 inches past the raised bead, then the insulation is pulled back
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To keep chase width to a minimum, use flat sheet metal as opposed to a collar and flex duct for supplies into rooms where the chase is located
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To measure air flow, a hole was made in this flex duct; a more accurate measurement could be taken if the duct material were rigid metal, not flex duct
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To prepare for a total duct test at final, cover all of the supply outlets and return inlets
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To prepare for a total duct test at rough-in, cover all of the supply outlets and return inlets
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Transfer grills and jump ducts provide pathways for air to reach the centrally located HVAC return grille, even when bedroom doors are shut.
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Trunk to duct connections are properly insulated and have been sealed with mastic
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Two pieces of flex duct are spliced together with a metal sleeve, nylon draw bands, mastic, metal tape, and more mastic
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Uninsulated, unsealed, or missing rim joists allow attic air and heat into the floor cavity
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Unsealed, uninsulated rim joists allow outside air and heat into the floor cavity
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Use masking tape as a removable sealer to stop air from leaking around the return grille filter.
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Ventilation air inlets ≥ 2 ft. above grade or roof deck in Climate Zones 1-3 or ≥ 4 ft. above grade or roof deck in Climate Zones 4-8 and not obstructed
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Ventilation air inlets located ≥10 ft. of stretched-string distance from known contamination sources such as stack, vent, exhaust hood, or vehicle exhaust
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Ventilation inlet is not near any exhaust outlets/contamination sources and is at least 2 ft. above the roof deck
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Ventilation inlet is too close to exhaust outlets and does not extend at least 2 ft. above the roof deck
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Well sealed duct lifted into raised ceiling chase
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When wrapping metal ducts with insulation allow two inches of overlap and staple along the seam with outward clinching staples
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Wide saddle support provides sturdy support for the turn without pinching the flex duct
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Wrong - Code requires a kitchen exhaust fan duct to be a smooth metal duct (galvanized steel, stainless steel, or copper) and to terminate outside, not in an attic or crawlspace.
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Wrong - Duct seams were sealed with regular duct tape which has failed to hold; seams should have been sealed with mastic or approved metal tape.
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Wrong - Flex duct insulation is overly compressed in 3 ways; Zip-tie fastener is over the insualtion not under the insulation at the duct boot collar, duct turning radius is too tight, and support strap is too tight.
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Wrong - Flex duct resting on floor compressing insulation and causing condensation
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Wrong - Flex ducts are prohibited by the IRC for kitchen exhaust and, at 28 feet, this duct is too long to be effective.
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Wrong - If this kitchen exhaust duct had been extended a few inches, at least one bend could have been eliminated.
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Wrong - Kitchen exhaust ducts are prohibited from terminating within 3 feet of an operable window or near gable vents.
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Wrong - Kitchen exhaust fans must be located directly over the stove top to be effective at capturing and removing cooking pollutants.
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Wrong - Metal tape is poorly adhered and metal duct and duct-to-subfloor seam is not sealed.
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Wrong - Not enough straps were used to hang this flex duct so it is sagging, restricting air flow
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Wrong - Penetrations in walls for ducts should be air sealed to reduce air leakage.
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Wrong - The furnace intake and exhaust are too close to each other and are missing rodent screening.
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Wrong - The furnace intake and exhaust are too close to each other and should be facing different directions.
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Wrong - The IRC prohibits the use of flex duct for kitchen exhaust and only permits PVC duct for downdraft systems that meet specific exceptions; also, gaps at the ceiling have not been air sealed.
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Wrong - The IRC requires that kitchen exhaust ducts terminate outside, at least 3 feet from operable windows.
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Wrong - The seam around the duct boot where the duct boot enters the trunk duct has not been completely sealed with mesh tape and mastic.
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Wrong - The support strap for the duct is too tight and the radius of the turn is too sharp.
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Wrong - This is a poorly sealed chase with no solid air barriers along the sides of the chase and no caulk around the electrical wires installed through the ceiling of the chase.
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Wrong - This kitchen exhaust duct uses flex duct, which is prohibited by code, and the duct’s 22-foot length and multiple bends will slow the movement of pollutants out of the home.
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Wrong -The duct does not have enough support so it is sagging and compressing the duct
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Wrong – A tear in the outer jacket of this duct shows where an in-line airflow measurement was made; the inner duct was not sealed and created a duct leak.
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Wrong – Don’t use nails to fasten poly vapor barrier around flex ducts; it will allow moist air to reach the ducts where it could condense and ruin the insulation.
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Wrong – Duct is pulling away from ceiling because it is not sealed to the ceiling
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Wrong – Exhaust fan ducts must be smooth metal ducts; flex duct is not permitted by the IRC.
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Wrong – Fiber board duct is not sealed at seams; flex duct is sealed with duct tape not mastic tape or UL-181 metal tape.
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Wrong – Insulation should not be pinched where flex ducts connect to the trunk duct as compression of the insulation here can lead to cold spots and condensation on the duct surface.
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Wrong – It is difficult to test the air flow in this fresh air intake duct due to poor access and inadequate length of straight duct to get an accurate in-line flow measurement.
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Wrong – The duct for this kitchen exhaust fan is made of flex duct instead of smooth metal duct and the duct is not properly supported.
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Wrong – the exhaust terminal for a clothes dryer should not be covered with a screen which could trap lint; instead, cover it with a hooded, louvered damper
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Wrong – the interior seam of the branch duct to trunk duct juncture is sealed with mastic but there are gaps around the exterior seam that should also be sealed with mastic or metal tape.
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Wrong – The kitchen exhaust fan duct is attached to flex duct, which is prohibited by code.
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Wrong – These flex ducts are pulled taut, which is correct but they are inadequately supported with straps that are spaced too far apart and are too tight causing pinching of the insulation and turns are sharp rather than gradual.
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Wrong – This exhaust fan duct is wrong on several counts: it uses flex duct rather than smooth round metal duct as required by the IRC, the duct terminates inside of the wall assembly instead of outside, the opening is not large enough...
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Wrong – This metal duct is crushed, is sealed with duct tape instead of mastic or UL-181 metal tape, and is not correctly supported.
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Wrong – Two combustion appliances are sharing a flue which could lead to backdrafting if one appliance is updated to a direct vent appliance and disconnected from shared chimney.
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Wrong –Excessive length and a vertical angle on this dryer duct reduced air flow allowing the dryer duct to become completely clogged with dryer lint
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Wrong- A tie strap should not be used over the duct outer liner because it can compress the insulation. Tuck in the fibrous insulation and seal the outer liner to the connecting duct with mastic or foil tape (Steven Winter Associates 2013).
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Wrong: Drywall does not extend beyond chase wall framing and is unsealed in a hallway dropped ceiling chase
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Wrong: Drywall does not extend beyond the top plate of the interior walls. This installation has the potential for leakage at the sides where the ducts penetrate the side walls of the chase
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Wrong: Ducts are held above the ceiling plane with strapping to provide a good angle into top-entry boots. Once the ceiling insulation is added, this duct will protrude from the ceiling insulation and will not be buried
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Wrong: Ducts are held from the rafters with strapping and a large beam prevents ducts from properly lying on the ceiling plane
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Wrong: Ducts are not laid across the lower truss cords or ceiling, but are hung from the rafters by straps. As a result, ductwork is not buried
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Wrong: Ductwork is not fully encapsulated with ccSPF insulation. The duct jacket is still fully visible at sections of the duct
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Wrong: Open wall cavities in the un-air-sealed return plenum connect the plenum to attic spaces
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Wrong: open wall cavity connected to this return air plenum is allowing cellulose attic insulation to be pulled into the furnace
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Wrong: The door and filter were removed, allowing unfiltered air to enter the air handler leading to premature failure of the system due to dirt accumulation.
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Wrong: The return plenum is not air sealed to separate it from the wall cavities and it should not be used for storage
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Wrong: This exhaust fan duct is too long and terminates in the attic instead of going through the roof and it is improperly supported; it needs straps all along its length to prevent sagging.
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Wrong: This return air plenum is not lined and air sealed
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Wrong: This wall cavity is open to the attic allowing unconditioned, attic air to enter the HVAC system, bypassing the filter, and degrading system life and performance