Heads up: There are no amended sections in this chapter.
  1. Introduction. The increased energy efficiency measures identified in this appendix are strictly voluntary at the option of the permit holder and have been evaluated to be the most cost effective measures for achieving an additional 10- to 15-percent energy efficiency beyond the code minimums.
  2. Requirements: Follow all sections of residential building provisions of the 2018 North Carolina Energy Conservation Code, except the following.
    1. Instead of using Table R402.1.2 in Section R402.1.2, use Table 4A shown below.
    2. Instead of using Table R402.1.4 in Section R402.1.4, use Table 4B to find the maximum U-factors for building components.
    3. For compliance with Section R402.4 Air leakage control (Mandatory), Sections R402.4.1 (Building thermal envelope) and R402.4.2.2 (Testing option) must be followed, with the maximum leakage rate shown below. Section R402.4.2.1 (Visual inspection option) cannot be used to show compliance.
      1. 0.24 CFM50/Square Foot of Surface Area (SFSA); or
      2. Four (4) air changes per hour (ACH50)
    4. Instead of using the duct leakage value for maximum leakage shown in Section R403.3.3 use the following:
      1. R403.3.3.1 Total duct leakage. Total duct leakage shall be less than or equal to 4 cfm (113 L/min) per 100 square feet (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure.
      2. R403.3.3.2 Duct leakage to the outside. Conduct the test using fan pressurization of distribution system and building at a fixed reference pressure for combined supply and return leak. Duct leakage to the outside shall be less than or equal to 3 cfm (85 L/min) per 100 square feet (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, relative to the outside, including the manufacturer's air handler enclosure.
    5. For compliance with Section R404.1 (Lighting equipment), the home must comply with the following:
Not less than 90 percent of the lamps in permanently installed lighting fixtures shall be high-efficacy lamps or not less than 90 percent of the permanently installed lighting fixtures shall contain only high-efficacy lamps.

TABLE 4A
INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENTa
CLIMATE ZONE FENESTRATION U-FACTORb, i SKYLIGHTb U-FACTOR GLAZED FENESTRATION SHGCb, k CEILING R-VALUEm WOOD FRAME WALL R-VALUE MASS WALL R-VALUEi FLOOR R-VALUE BASEMENTc, o WALL R-VALUE SLABd R-VALUE & DEPTH CRAWL SPACEc WALL R-VALUE
3 0.32 0.55 0.25 38 or 30 cil 19, 13+5, or 15+3h 5/13 or 5/10ci 19 5/13f 5 5/13
4 0.32 0.55 0.25 38 or 30cil 19, 13+5, or 15+3h 5/13 or 5/10ci 19 10/15 10 10/15
5 0.32 0.55 (NR) 38 or 30cil 19, 13+5, or 15+3h 13/17 or 13/12.5 ci 30g 10/15 10 10/19
For SI: 1 foot = 304.8 mm.
  1. R-values are minimums. U-factors and SHGC are maximums. When insulation is installed in a cavity which is less than the label or design thickness of the insulation, the installed R-value of the insulation shall not be less than the R-value specified in the table.
  2. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration.
  3. "10/15" means R-10 continuous insulated sheathing on the interior or exterior of the home or R-15 cavity insulation at the interior of the basement wall or crawl space wall.
  4. For monolithic slabs, insulation shall be applied from the inspection gap downward to the bottom of the footing or a maximum of 24 inches below grade, whichever is less. For floating slabs, insulation shall extend to the bottom of the foundation wall or 24 inches, whichever is less (see Appendix R2). R-5 shall be added to the required slab edge R-values for heated slabs.
  5. Deleted.
  6. Basement wall insulation is not required in warm-humid locations as defined by Figure R301.1 and Table R301.1.
  7. Or insulation sufficient to fill the framing cavity, R-19 minimum.
  8. The first value is cavity insulation, the second value is continuous insulation, so "13+5" means R-13 cavity insulation plus R-5 continuous insulation. If structural sheathing covers 25 percent or less of the exterior, insulating sheathing is not required where structural sheathing is used. If structural sheathing covers more than 25 percent of exterior, structural sheathing shall be supplemented with insulated sheathing of at least R-2.
  9. The second R-value applies when more than half the insulation is on the interior of the mass wall.
  10. In addition to the exemption in Section R402.3.3, a maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.
  11. In addition to the exemption in Section R402.3.3, a maximum of two glazed fenestration product assemblies having a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.
  12. R-30 shall be deemed to satisfy the ceiling insulation requirement wherever the full height of uncompressed R-30 insulation extends over the wall top plate at the eaves. Otherwise R-38 insulation is required where adequate clearance exists or insulation must extend to either the insulation baffle or within 1 inch of the attic roof deck.
  13. Table value required except for roof edge where the space is limited by the pitch of the roof, there the insulation must fill the space up to the air baffle.
  14. R -19 fiberglass batts compressed and installed in a nominal 2 × 6 framing cavity is deemed to comply. Fiberglass batts rated R-19 or higher compressed and installed in a 2 × 4 wall is not deemed to comply.
  15. Basement wall meeting the minimum mass wall specific heat content requirement may use the mass wall R-value as the minimum requirement.
TABLE 4B
EQUIVALENT U-FACTORSa
CLIMATE ZONE FENESTRATION U-FACTORd SKYLIGHT U-FACTOR CEILING U-FACTOR FRAME WALL U-FACTOR MASS WALL U-FACTORb FLOOR U-FACTOR BASEMENT WALL U-FACTORc CRAWL SPACE WALL U-FACTOR
3 0.32 0.55 0.030 0.061 0.141 0.047 0.091 0.136
4 0.32 0.55 0.030 0.061 0.141 0.047 0.059 0.065
5 0.32 0.55 0.030 0.061 0.082 0.033 0.059 0.065
  1. Nonfenestration U-factors shall be obtained from measurement, calculation or an approved source.
  2. When more than half the insulation is on the interior, the mass wall U-factors shall be a maximum of 0.07 in Climate Zone 3, 0.07 in Climate Zone 4, and 0.054 in Climate Zone 5.
  3. Basement wall U-factor of 0.360 in warm-humid locations as defined by Figure R301.1 and Table R301.1.
  4. A maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 and a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.

Table R4C
Sample Confirmation Form for ADDITIONAL VOLUNTARY CRITERIA FOR INCREASING
ENERGY EFFICIENCY (High-Efficiency Residential Option)
NORTH CAROLINA ENERGY CONSERVATION CODE:
HIGH-EFFICIENCY RESIDENTIAL OPTION, INSULATION AND FENESTRATION VALUES
(Notes correlate to Table R4A)
PROPOSED PROJECT VALUES
Climate Zone 3 4 5
Fenestration U-Factorb, j 0.32 0.32 0.32
Skylight U-Factorb 0.55 0.55 0.55
Glazed Fenestration SHGCb, k 0.25 0.25 (NR)
Ceiling R-valuem 38 or 30 cil 38 or 30 cil 38 or 30 cil
Wood Frame Wall R-valueh 19, 13+5, or 15+3 19, 13+5, or 15+3 19, 13+5, or 15+3
Mass Wall R-valuei 5/13 or 5/10ci 5/13 or 5/10ci 13/17 or 13/12.5ci
Floor R-value 19 19 30g
Basement Wall R-valuec, o 5/13f 10/15 10/15
Slab R-value and Depthd 5 10 10
Crawl Space Wall R-valuec 5/13 10/15 10/19
* Note: ci = continuous insulation
High Efficacy Lighting
% of lighting that is high efficacy according to R404.1 (90% required)
Building Air Leakage
Building Air Leakage Test according to R402.4.2.2 (check box). Show test value:
ACH50 [Target: 4.0], or
CFM50/SFSA [Target: 0.24]
Name of Tester / Company:
Date: Phone:
Duct Insulation and Sealing
Insulation Value R-
Duct Leakage Test Result (Sect. R403.3.3)
(CFM25 Total/100SF) [Target: 4 Total/ 3 To exterior] □Total duct leakage or □Duct leakage to the exterior
Name of Tester or Company:
Date: Phone:


R4D:
SAMPLE WORKSHEETS FOR RESIDENTIAL AIR AND DUCT LEAKAGE TESTING

R4D.1
Air sealing: Testing (Section R402.4.2.2)
Sample Worksheet for Alternative Residential Energy Code for Higher Efficiency


Air sealing. Building envelope air tightness shall be demonstrated by Section R402.4.2.2:

Air sealing: Testing (Section R402.4.2.2)
Sample Worksheet for Alternative Residential Energy Code for Higher Efficiency


N1102.4.2.2 Testing. Building envelope tightness shall be considered acceptable when items providing insulation enclosure in R402.2.14 and enclosure and air sealing in Section R402.2.15 and air sealing in Section R402.4.1 are addressed and when tested air leakage is less than or equal to one of the two following performance measurements:
  1. 0.24 CFM50 (6.8 L/min)/Square Foot of Surface Area (SFSA) or
  2. Four (4) air changes per hour (ACH50)
     When tested with a blower door fan assembly, at a pressure of 0.2 inches water gauge (50 Pa), a single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the blower door fan assembly has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E779—03. Testing shall occur after rough in and after installation of penetrations of the building envelope, including penetrations for utilities, plumbing, electrical, ventilation and combustion appliances. Testing shall be reported by the permit holder, a North Carolina licensed general contractor, a North Carolina licensed HVAC contractor, a North Carolina licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater.

During testing:
  1. Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed;
  2. Dampers shall be closed, but not sealed, including exhaust, backdraft, and flue dampers;
  3. Interior doors shall be open;
  4. Exterior openings for continuous ventilation systems, air intake ducted to the return side of the conditioning system, and energy or heat recovery ventilators shall be closed and sealed;
  5. Heating and cooling system(s) shall be turned off; and
  6. Supply and return registers shall not be sealed.
     The air leakage information, including building air leakage result, tester name, date, and contact information, shall be included on the certificate described in Section R401.3.

For Test Criteria 1 above, the report shall be produced in the following manner: Perform the blower door test and record the CFM50______. Calculate the total square feet of surface area for the building thermal envelope, all floors, ceilings, and walls (this includes windows and doors) and record the area_______. Divide CFM50 by the total square feet and record the result below. If the result is less than or equal to [0.24 CFM50/SFSA] the envelope tightness is acceptable; or

For Test Criteria 2 above, the report shall be produced in the following manner: Perform a blower door test and record the CFM50 = ______. Multiply the CFM50 by 60 minutes to create CF/Hour50 and record = _______. Then calculate the total conditioned volume of the home and record = _________cubic feet. Divide the CF/Hour50 by the total volume and record the result = ___________ ACH50. If the result is less than or equal to [4 ACH50] the envelope tightness is acceptable.

Property Address:_________________________________________________________________________
Fan attachment location_________________________    Company Name________________
Contact Information:______________________________________________________________________
__________________________________________    _________________________________
Signature of Tester                                                         Date


Permit Holder, NC Licensed General Contractor, NC Licensed HVAC Contractor, NC Licensed Home Inspector, Registered Design Professional, Certified BPI Envelope Professional, or Certified HERS Rater

(circle one)


R4D.2
Duct sealing. Duct air leakage test (Section R403.3.3)
Sample Worksheet for Alternative Residential Energy Code for Higher Efficiency


R403.3.3 Duct leakage (Prescriptive) and Duct Testing (Mandatory). Duct testing and duct leakage shall be verified by compliance with either Section R403.3.3.1 or R403.3.3.2. Duct testing shall be performed and reported by the permit holder, a North Carolina licensed general contractor, a North Carolina licensed HVAC contractor, a North Carolina licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater. A single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the duct testing fan assembly(s) has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E1554—07.

The duct leakage information, including duct leakage test selected and result, tester name, date, and contact information, shall be included on the certificate described in Section R401.3.

For the Test Criteria, the report shall be produced in the following manner: perform the HVAC system air leakage test and record the CFM25. Calculate the total square feet of Conditioned Floor Area (CFA) served by that system. Multiply CFM25 by 100, divide the result by the CFA and record the result. If the result is less than or equal to 4 CFM25/100SF for the "Total duct leakage test" or less than or equal to 3 CFM25/100SF for the "Duct leakage to the outside" test, then the HVAC system air tightness is acceptable.

Exceptions to testing requirements:
  1. Duct systems or portions thereof inside the building thermal envelope shall not be required to be leak tested.
  2. Installation of a partial system as part of replacement, renovation or addition does not require a duct leakage test.

    R403.3.3.1 Total duct leakage. Total duct leakage less than or equal to 4 cfm (113 L/min) per 100 square feet (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure. During testing:
    1. Block, if present, ventilation air duct(s) connected to the conditioning system.
    2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
    3. The filter shall be removed and the air handler power shall be turned off.
    4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight.
    5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
    6. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage.
    R403.3.3.2 Duct leakage to the outside. Conduct the test using fan pressurization of distribution system and building at a fixed reference pressure for combined supply and return leak. Duct leakage to the outside shall be less than or equal to 3 cfm (85 L/min) per 100 square feet (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, relative to the outside, including the manufacturer's air handler enclosure.

    During testing:
    1. Block, if present, the ventilation air duct(s) connected to the conditioning system.
    2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
    3. The filter shall be removed and the air handler power shall be turned off.
    4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight or as tight as possible.
    5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
    6. Open all interconnecting doors in the building, close dampers for fireplaces and other operable dampers.
    7. Set up an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door, following the manufacturer's prescribed procedure.
    8. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage used in combination with a blower door. Typical steps are as follows:
      1. Depressurize the ductwork system to 25 Pa using the measurement hose in Step 5 above.
      2. Depressurize the house to 25 Pa using an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door.
      3. Correct the duct pressure to measure 0 Pa of pressure differential between the house and the ductwork system.
      4. Read the cfm of duct leakage using the procedures for the specific equipment being used. (Note that most automatically calculating pressure gauges cannot compute the CFM25 automatically with a duct-to-house difference in pressure of 0 Pa, so the gauge setting should be set to read CFM instead of CFM25).
Complete one duct leakage report for each HVAC system serving the home:

Property Address:_______________________________________________________________

HAVC System Number:_____________Describe area of home served:____________________
CFM25 Total_______. Conditioned Floor Area (CFA) served by system:_________s.f.
CFM25 x 100 divided by CFA =____CFM25/100SF (e.g. 100 CFM25 x 100/2,000 CFA = 5 CFM25/100SF)

Fan attachment location_________________________

Company Name__________________________________________________________________

Contact Information:____________________________________________________________

_________________________________________________________________________________

_____________________________________      _________________________
Signature of Tester                                                Date


Permit Holder, NC Licensed General Contractor, NC Licensed HVAC Contractor, NC Licensed Home Inspector, Registered Design Professional, Certified BPI Envelope Professional, or Certified HERS Rater

(circle one)
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