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This constant airflow regulator (CAR) has been fouled by deposition of aerosolized sealant because it was not protected during duct sealing

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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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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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Right – The hard metal ducts are located in conditioned space between floor joists and all seams are sealed with approved metal tape.

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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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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 – This duct boot is sealed inside the boot for a duct leakage test; this fails to account for the ductwork leakage between the duct boot and the wall board

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Building America Top Innovations 2014: HVAC Cabinet Air Leakage Test Method

Case Study

Case study describing a 2014 DOE Building America Top Innovation on development of a standardized testing method for testing the air leakage of HVAC air handlers and furnace cabinets developed by Lawrence Berkeley National Laboratory.

Use masking tape as a removable sealer to stop air from leaking around the return grille filter.

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The hole in the drywall was cut overly large for this heating register, allowing air to leak into or out of the wall cavities.

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This air register has noticeable gaps between it and the floor; use canned spray foam to fill in the gaps.

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Install sheet metal to cover the gaps around a flue pipe in the attic; attach with screws or heavy staples, then seal seams with fire-rated caulk or foam

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This constant airflow regulator (CAR) has been fouled by aerosolized sealant because it was not covered while the ducts were being sealed with the aerosolized acrylic sealant.

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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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Furnace and chimney flues often have large gaps around them that allow air leakage from the home into the attic.

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The dark streaks seen in this infrared camera image of a return vent in a ceiling indicate cooler air is leaking in around the vent.

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Right - This duct penetration is properly flashed and integrated with the taped, foil-faced foam sheathing layer, which serves as the air and water barrier

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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

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With the register grill removed, very large gaps are visible around the edges of this duct boot between the duct boot and the drywall; the gaps can be closed with screw or heavy staples then sealed with caulk, mastic, or metal tape.

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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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Conducting a Residential Duct Leakage Test and Blower Door Test: Quick and easy set up of the blower door and determination of whole house air leakage

Video

Video describing how to conduct a residential blower door and duct blaster test, including an efficient method for setting up the blower door equipment and how to set up the fan rings and the manometer. Video 4 of 9.

This exhaust fan duct opens into the attic rather than exiting through the roof and mold has begun to form on the underside of the deck sheathing and on the rafter due to the moist air exiting the duct

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ANSI/RESNET/ICC 380: Standard for Testing Airtightness of Building, Dwelling Unit, and Sleeping Unit Enclosures; Airtightness of Heating and Cooling Air Distribution Systems; and Airflow of Mechanical Ventilation Systems

Reference

This ANSI/RESNET/ICC standard provides a consistent, uniform methodology for evaluating the airtightness of building, dwelling unit, and sleeping unit enclosures and heating and cooling air distribution systems, and the air flows of mechanical ventilation systems.

This constant airflow regulator (CAR) has been fouled by deposition of aerosolized sealant because it was not protected during duct sealing

Seal all wood framing joints surrounding the chase with sealant and lay a bead of sealant on top edge of chase framing

Wrong – This metal duct is crushed, is sealed with duct tape instead of mastic or UL-181 metal tape, and is not correctly supported.

Right – The hard metal ducts are located in conditioned space between floor joists and all seams are sealed with approved metal tape.

Seal all wood framing joints surrounding the chase with sealant and lay a bead of sealant along top edge of chase framing

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.

Wrong – This duct boot is sealed inside the boot for a duct leakage test; this fails to account for the ductwork leakage between the duct boot and the wall board

Building America Top Innovations 2014: HVAC Cabinet Air Leakage Test Method

Use masking tape as a removable sealer to stop air from leaking around the return grille filter.

The hole in the drywall was cut overly large for this heating register, allowing air to leak into or out of the wall cavities.

This air register has noticeable gaps between it and the floor; use canned spray foam to fill in the gaps.

Install sheet metal to cover the gaps around a flue pipe in the attic; attach with screws or heavy staples, then seal seams with fire-rated caulk or foam

This constant airflow regulator (CAR) has been fouled by aerosolized sealant because it was not covered while the ducts were being sealed with the aerosolized acrylic sealant.

Wrong: open wall cavity connected to this return air plenum is allowing cellulose attic insulation to be pulled into the furnace

Furnace and chimney flues often have large gaps around them that allow air leakage from the home into the attic.

The dark streaks seen in this infrared camera image of a return vent in a ceiling indicate cooler air is leaking in around the vent.

Right - This duct penetration is properly flashed and integrated with the taped, foil-faced foam sheathing layer, which serves as the air and water barrier

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

With the register grill removed, very large gaps are visible around the edges of this duct boot between the duct boot and the drywall; the gaps can be closed with screw or heavy staples then sealed with caulk, mastic, or metal tape.

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).

Conducting a Residential Duct Leakage Test and Blower Door Test: Quick and easy set up of the blower door and determination of whole house air leakage

This exhaust fan duct opens into the attic rather than exiting through the roof and mold has begun to form on the underside of the deck sheathing and on the rafter due to the moist air exiting the duct

ANSI/RESNET/ICC 380: Standard for Testing Airtightness of Building, Dwelling Unit, and Sleeping Unit Enclosures; Airtightness of Heating and Cooling Air Distribution Systems; and Airflow of Mechanical Ventilation Systems

Encapsulated Ducts

Injected Spray Sealant for Existing HVAC Ducts

Existing Whole-House Solutions Case Study: Deep Energy Retrofit in the Pacific Northwest

Ducts in Raised Ceiling Sections

Total Duct Leakage Tests

Eaglesprings and Waterhaven Communities

Ventilating Your Home