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Home Air Sealing

Installed correctly, home air sealing can reduce utility costs while improving comfort, indoor air quality, and durability.

There are extensive holes, cracks, and missing air barriers in older homes that allow unwanted heat loss in cold weather, heat gain in hot weather, and infiltration of contaminants year-round. Air sealing uncontrolled leaks is one of the most cost-effective measures to improve your home’s performance. It can reduce your heating and cooling bills, improve comfort by reducing drafts, keep contaminants such as moisture, dust, pollen, and pests from entering your home, and reduce moisture-related durability problems.

Checklist

This U.S. Department of Energy checklist includes important specifications that can contribute to a complete and quality installation. All work shall comply with these specifications, all relevant codes and standards, and all manufacturer installation instructions. The contractor shall check each box on the checklist below and sign and date at the bottom to certify the work is completed.

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Preparation


A general inspection of the home for water leaks and moisture, structural, and pest damage shall be performed. A list of all needed repairs shall be provided to the homeowner before air sealing work begins so remediation can be fully addressed as necessary.

Before work is performed, air tightness shall be tested with a blower door test according to the Residential Energy Network (RESNET) Standards for Air Leakage Testing. Based on the pre-test, a targeted level of air tightness shall be determined and provided to the owner.

A combustion safety test shall be performed if any atmospheric vented combustion equipment exists in the home to ensure there is no back-drafting or spillage of combustion fumes. Any combustion safety issues shall be addressed before proceeding with air sealing.

Installation


All gaps, cracks, seams, and penetrations between conditioned and unconditioned space (such as gaps around lighting fixtures, HVAC duct boots, electric wiring, plumbing pipes, and flues) shall be sealed with sealants alone (e.g., caulk, foam, aerosol sealant) if the gaps are narrow enough or, for larger gaps, with rigid blocking material sealed in place with sealants, per the sealant the manufacturer’s instructions. Fibrous insulation is not an air barrier and shall not be used for air sealing.

The seams where drywall attaches to the top plate at all interior and exterior walls shall be sealed from the attic side with a caulk, spray foam, or sprayer-applied sealant.

Larger gaps and openings (such as uncovered dropped soffits and openings under knee walls or at the tops of balloon-framed gable walls) shall be closed off using a solid material such as rigid foam or OSB that is sealed at the edges with caulk, sealant, or mastic.

Gaps around masonry chimneys or gas appliance vents shall be sealed with high-temperature-rated caulk or foam in accordance with building code requirements.

A continuous gasket, such as weather stripping, shall be installed around all exterior door openings.

Indoor sealants shall be low volatile organic compound (VOC) products that meet independent testing and verification protocols, such as Green Seal, GREENGUARD, or comparable certifications.

Commissioning


After air sealing, a combustion safety test shall be performed if any natural draft combustion equipment exists in the home to ensure there is no back-drafting or spillage of combustion gases. Recommendations for remediation shall be made to the homeowner where combustion safety issues are identified.

The home shall be inspected for the presence of a whole-house ventilation system. If one is present, the actual air flow shall be tested and verified to meet a target ventilation rate based on house size as follows: 50 cfm for up to 1,500 ft2, 70 cfm for 1,501 to 2,500 ft2, and 100 cfm for over 1,500 ft2, per ASHRAE 62.2-2013. If the home has no whole-house ventilation system, or if the existing system does not meet the target ventilation rate, recommendation shall be made to the homeowner to either install a new system or repair the existing system to meet the target ventilation rate.

At the completion of the work, a radon test kit shall be provided to the homeowner with a recommendations for a radon remediation strategy if radon measurements exceed EPA acceptable levels.

Air tightness shall be tested with a blower door test according to RESNET Standards for Air Distribution Leakage Testing after air sealing is performed and results shall be provided to the owner to verify that air tightness levels meet or exceed the target levels.
Home Air Sealing

Tips to Sell Quality Installed Home Improvements

Home Improvement Expert is a valuable tool for organizations committed to quality installed work. The following tips help optimize the value of this tool when selling home improvements:

Trust Matters: Inform homeowners how your work conforms to this world-class expert guidance. Recommend they visit the DOE website as evidence these are indeed official best practices.

Knowledge Matters: Take advantage of the Building America Solution Center as a resource for becoming an expert on these projects.

Clarity Matters: Tell prospective clients to contrast your expert-recommended best practices with other contractors.

Value Matters: Advise prospective clients to insist other bids also include these checklists to ensure equivalent quality work.

Message Matters: Showcase on your website and marketing materials that your company uses the highest quality best practices specified on HIE Checklists.

Experiences Matter: Provide visual evidence contrasting the difference between poor and high quality work such as infrared images; pre- and post-energy bills; short and long warranties; and simple charts and graphics depicting performance advantages.

Related Guides

Guide:

Enclosure Leakage Test

Description
Guide describing how to use a blower door test to determine building envelope air leakage.
Guide:

Air Sealed, Insulated Basements

Description
Guide describing how to insulate a basement to improve the overall thermal performance of the building and provide more dry, usable conditioned space for home occupants and HVAC equipment.
Guide:

Roof/Attic to Exterior Wall Air Control Upgrade

Description
Guide describing how to retrofit an exterior wall and/or attic to provide continuous air sealing.

Disclaimer

This content is a work created with funding provided by the United States Department of Energy under Contract no DE-AC05-076RL01830 for the operation of Pacific Northwest National Laboratory. The information and guidance provided by Pacific Northwest National Laboratory (PNNL) in the content are intended solely for educational purposes only and do not constitute formal training or certification. It is provided with the explicit understanding that neither the United States Government nor the United States Department of Energy, nor the Contractor, nor any or their employees, nor any jurisdiction or organization that has cooperated in the development of these materials, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product, software, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Viewers assumes full responsibility for all actions that they may take from information provided in this content including ensuring the safety, code compliance, and proper functionality of any products they choose to install. Installation and use of such products should be performed in accordance with local regulations and manufacturer instructions.