U.S. Department of Energy U.S. Department of Energy Energy Efficiency and Renewable Energy

Electrical Wiring

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Electrical wiring

Scope


Air Sealing

 

Electrical Wiring

  1. Using a saw or drill, cleanly cut all penetrating holes no more than 1 inch larger in diameter than the penetrating object to allow for proper air sealing.
  2. Seal all gaps and holes to unconditioned space with caulk or foam. Fibrous insulation is not an air barrier and cannot be used for sealing gaps.

 

 

 

 

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Description


Air can pass through tiny gaps around electrical wiring and holes in electrical boxes, carrying conditioned air into wall cavities and up into unconditioned attics or allowing air from unconditioned garages and crawlspaces into living spaces. Pressure and temperature differences between conditioned and unconditioned spaces encourage this air flow. These air leaks represent energy losses, and they could also potentially allow warm, moisture-laden air into unconditioned spaces where it can condense on cold surfaces creating moisture problems. Conversely, air leaking into the house from the garage or crawlspace can affect indoor air quality and cause drafts. Air barriers need to be continuous to be effective; this means sealing all penetrations in exterior walls and in walls, ceilings, or floors adjoining unconditioned spaces. Holes drilled through studs and top and bottom plates should be caulked or foam sealed to prevent air from following the wiring through wall cavities.

Be sure to schedule caulking of electrical penetrations after the wiring has been installed and before the drywall is completed. Responsibility for sealing air leaks around electrical wiring and electrical boxes should be included in the contract for the appropriate trade, depending on the workflow at specific job sites.

 

How to Air Seal Electrical Boxes and Wiring

1. For ceiling-mounted electrical boxes, install the electrical box in the ceiling drywall, then caulk around the base and caulk all holes in the box with fire-retardant caulk.

 

 

Caulk electrical boxes mounted in the ceilingReference

 

 

2.  For wall-mounted electrical boxes, specify that the electrician install prefabricated, airtight electric boxes that have flexible boot seals at wire penetrations and a gasketed flange at the face.

 

Air-tight electrical boxes have built-in gaskets and self-sealing wire holesReference

 

 

Or, as another option, install standard electrical boxes and caulk all of the openings in the box (including around wire penetrations), then seal the face of the box to the drywall with caulk.

 

Caulk holes in the electrical box, caulk the wire holes, and caulk the face of the box to the drywallReference

 

 

3.  Seal all wiring holes through the exterior walls of the house, such as holes for electrical wiring, security system wiring, television and telephone cables, porch light fixtures, and exterior electrical outlets. Use caulk, gaskets, or spray foam (note that spray foam degrades in sunlight).

 

Air seal the electrical panelReference

 

 

4.  Use caulk or canned spray foam to seal wiring holes through all top plates and bottom plates.

 

Foam wiring holes in top plateReference



Ensuring Success


Holes around wiring should be visually checked to see if caulk and canned spray foam have been applied before insulation and drywall are installed. Blower door testing, which is conducted as part of the whole-house energy performance test-out, may help indicate whether holes for electrical wiring in exterior walls have been successfully sealed. An experienced technician can also check for air leaks with a smoke pencil or by feeling with the back of the hand.



Climate


No climate specific information applies.



Right and Wrong Images



Presentations

None Available



Videos

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CAD Images




Compliance


ENERGY STAR Version 3 (Rev. 6)

Thermal Enclosure Checklist, Air Sealing. Penetrations to unconditioned space fully sealed with solid blocking or flashing as needed and gaps sealed with caulk or foam.

 

DOE Challenge Home

Exhibit 1: Mandatory Requirements.  Certified under ENERGY STAR Qualified Homes Version 3.

 

2009 IECC

Table R402.4.1.1 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed. Table R402.4.1.1 Air Barrier and Insulation Installation, Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.*

 

2009 IRC

Table N11402.4.2 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed. Table N11402.4.2 Air Barrier and Insulation Installation, Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.*

 

2012 IECC

Table R402.4.1.1 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed. Table R402.4.1.1 Air Barrier and Insulation Installation, Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.*

 

2012 IRC

Table N11402.4.1.1 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed. Table N1102.4.1.1 Air Barrier and Insulation Installation, Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.*

 

 

*Due to copyright restrictions, exact code text is not provided. For specific code text, refer to the applicable code.



Case Studies

  1. Attention to Detail in High-Performance Homes 2012

    PNNL 2012. Building America Case Study Technology Solutions for New Homes: Attention to Detail in High-Performance Homes 2012. PNNL-SA-91087. Prepared by the Pacific Northwest National Laboratory for the U.S. Department of Energy Building America Program.

    Link to Document
  2. Preventing Thermal Bypass

    PNNL. 2012. Building America Case Study Technology Solutions for New Homes: Preventing Thermal Bypass. PNNL-SA-91163. Prepared by the Pacific Northwest National Laboratory for the U.S. Department of Energy Building America Program.

    Link to Document

References

  1. 2009 IECC—International Energy Conservation Code

    2009 IECC, International Energy Conservation Code. International Code Council, Washington, D.C.

  2. 2009 IRC—International Residential Code for One and Two Family Dwellings

    2009 IRC, International Residential Code for One and Two Family Dwellings. 2009. Fifth Printing. International Code Council, Washington, D.C. 

  3. 2012 IECC—International Energy Conservation Code

    2012 IECC, International Energy Conservation Code.  International Code Council, Washington, D.C.

  4. 2012 IRC—International Residential Code for One and Two Family Dwellings

    2012 IRC, International Residential Code for One and Two Family Dwellings. 2012. Second Printing. International Code Council, Washington, D.C.

  5. Air Barriers-Airtight Drywall Approach, Information Sheet 401

    Lstiburek, J. 2009. Air Barriers-Airtight Drywall Approach. Information Sheet 401. Prepared by the Building Science Corporation for the Department of Energy's Building America Program.

  6. Building America Best Practices Series Volume 12: 40% Whole-House Energy Savings in the Cold and Very Cold Climates

    Baechler MC, TL Gilbride, MG Hefty, PC Cole, and PM Love.  2011.  Building America Best Practices Series Volume 12: 40% Whole-House Energy Savings in the Cold and Very Cold Climates. PNNL-20139. Prepared by Pacific Northwest National Laboratory for the U.S. Department of Energy, Building America Program.

  7. DOE Challenge Home National Program Requirements

    DOE. 2012. DOE Challenge Home National Program Requirements (Rev. 02). Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy, Washington, D.C.

  8. ENERGY STAR Qualified Homes, Version 3 (Rev. 06) Inspection Checklist for National Program Requirements

    EPA. 2012. ENERGY STAR Qualified Homes, Version 3 (Rev. 06) Inspection Checklist for National Program Requirements. U.S. Environmental Protection Agency, Washington, D.C.

  9. Guide to Attic Air Sealing

    Lstiburek, J. 2010. Guide to Attic Air Sealing. Prepared by the Building Science Corporation for the U.S. Department of Energy, Building America Program.

  10. Thermal Enclosure System Rater Checklist Guidebook

    EPA. 2011. Thermal Enclosure System Rater Checklist Guidebook. U.S. Environmental Protection Agency, Washington, D.C.



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