New Energy Code

R1101.1 Scope

This chapter establishes minimum thermal-performance requirements for the buildingenvelope of residential structures regulated by this code.

R1101.2 General

The building envelope shall be constructed to limit heatloss and gain through its components by providing insulation values not lessthan those specified in this chapter.

R1101.3.1 Prescriptive Compliance

The building thermal envelope shall meet or exceed theminimum R-values and maximum U-factors in Section R1102.2.

R1101.3.2 Performance Compliance

As an alternative to Section R1101.3.1, compliance may bedemonstrated using U.S. DOE REScheck, provided the proposed design achieves anoverall envelope performance not less than 5% above the current Utah 2012REScheck standard, as documented on the REScheck compliance certificate orachieve a HERs rating of 67 or better.

R1102.1 Building Thermal Envelope

The building thermal envelope shall include exterior walls,roof/ceiling assemblies, floors over unconditioned spaces, windows, doors, andother elements that enclose conditioned space.

R1102.2 Minimum Thermal Resistance (R-Values) and U-Factors

Insulation for each component of the building envelope shallmeet or exceed the following minimum R-values and U-factors.
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Component    MinimumR-Value / Maximum U-Factor Notes
Above-grade exterior walls   R-21   Applies to all framed or masonry wallsseparating conditioned and unconditioned space or the exterior environment.
Ceilings / roof assemblies     R-38     Applies to the thermal boundary betweenconditioned space and unconditioned attic or exterior air.
Floors over unconditioned space     R-30     Includes floorsover crawl spaces, garages, or open air.
Basement walls (conditioned basements) R-10 continuous or R-13 cavity               Required for any portion ofbasement walls enclosing conditioned space.
Windows and glazed doors   MaximumU-factor = 0.32      Applies to allfenestration enclosing conditioned space.
Skylights           MaximumU-factor = 1.3        Applies to allskylights over conditioned space.
Opaque doors               MinimumU-factor = 0.6         Applies to soliddoors separating conditioned and unconditioned spaces.

R1102.2.1 Conversion for Imported Windows and Doors

A conversion factor of 5.678 shall be used to convertU-values expressed in SI units to IP units. U(IP) =U(SI) / 5.678

R1102.3 Installation

Insulation materials shall be installed in substantialcontact with the surface they are intended to insulate and in accordance withthe manufacturer's instructions. Compressed or poorly fitted insulation shallnot be permitted where it reduces effective thermal resistance.

R1102.4 Verification

Compliance with the requirements of this chapter shall beverified by inspection prior to the installation of interior finishes. Noadditional energy modeling, trade-off analysis, or performance-baseddocumentation shall be required.

R1103 Mechanical Room Requirements

Mechanical rooms that receive combustion air fromunconditioned space shall be insulated and sealed to prevent uncontrolled airinfiltration.
 Such rooms shall: 
• Be separated from unconditioned spaces by an insulatedthermal barrier equal to the minimum wall R-value of R13.
• Be sealed to limit air leakage through joints,penetrations, and construction openings with the air-sealing provisions.

R1104 Duct System Testing and Insulation

R1104.1 Duct Leakage Testing

Duct systems located in unconditioned attics shall be testedfor total air leakage.

R1104.1.1 Air Handler Installed at Time of Test

Where the air handler is installed at the time of theleakage test, the total leakage shall be less than or equal to:
 6.0 cubic feet per minute (170 L/min) per 100 square feet(9.29 m²) of conditioned floor area.

R1104.1.2 Air Handler Not Installed at Time of Test

Where the air handler is not installed at the time of thetest, the total leakage shall be less than or equal to:
 5.0 cubic feet per minute (141 L/min) per 100 square feet(9.29 m²) of conditioned floor area.

R1104.2 Duct Insulation

Duct systems located outside conditioned space shall beinsulated to a minimum of R-8. Ducts buried beneath concrete floors do not requireinsulation.

R1104.1.3 Building Thermal Envelope Air Leakage Testing

The building thermal envelope shall be tested to determineair leakage rate. 
Testing shall be conducted in accordance with ASTM E779 orASTM E1827. 
A written report of the results of the test shall be signedby the party conducting the test and shall be provided to the code official.
 Testing shall be performed at a pressure differential of: 
0.2 inch water gauge (50 Pascals).

R1104.1.3.1 Mechanical Ventilation

Where the tested air leakage rate is not greater than 3 airchanges per hour, the dwelling unit shall be provided with whole-housemechanical ventilation in accordance with Section M1505.

R1104.1.3.2 Mechanical Ventilation as an Alternative

In lieu of the testing required by Section R1104.1.3, thedwelling unit shall be provided with mechanical ventilation in accordance withSection M1505.

R1105 Building Thermal Envelope Air Leakage Testing

The building thermal envelope shall be tested to determineair leakage rate. 
Maximum air leakage rates shall not exceed: 
• 5.0 air changes per hour OR
• 0.25 cubic feet per minute (CFM) per square foot ofdwelling unit enclosure area for single-family construction. 
For multifamily construction:
 • 6.0 air changes per hour OR
• 0.28 cubic feet per minute (CFM) per square foot ofdwelling unit enclosure area. 
Testing shall be conducted in accordance with ASTM E779 orASTM E1827. 
A written report of the results of the test shall be signedby the party conducting the test and shall be provided to the code official.
 Testing shall be performed at a pressure differential of: 
0.2 inch water gauge (50 Pascals). 
Approved parties to conduct testing include:
 • Parties certified by BPI• Parties certified by RESNET
• Licensed contractors who have completed training providedby blower door test equipment manufacturers or other comparable training. 
Exception to air leakage testing:
Table R41105 may be used as an alternative to conducting airleakage testing.

Table R41105

Air Barrier, Air Sealing, and Insulation Installation Checklist
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• Insulation and air barriers installed in accordance withmanufacturers instructions.
• Air-permeable insulation (fiberglass, rock-wool,cellulose) is not used for air sealing.
• Closed-cell foam is the only insulation that also servesas an air barrier.
• Continuous air barrier installed at the building thermalenvelope. Breaks and joints sealed.
• Dropped ceilings, soffits, shafts, and chases capped withan air barrier lid and sealed.
• Walls framed to allow insulation in corners and headers.
• Wall insulation enclosed on 6 sides including backside ofknee-walls.
• Wall batt insulation cut around pipes, wiring and boxes incavity.
• All gaps and voids sealed between conditioned andunconditioned spaces.
• Rim joist insulation includes sealed air barrier or closedcell spray foam.
• Floor insulation in contact with sheathing or lid below.
• Air barrier installed on underside of cantilevers.
• Fill floor cavities in rooms over garages.
• Recessed lights, boxes and HVAC boots penetrating thermalenvelope sealed.
• Air barrier behind electrical boxes or sealed with foam,caulk, gaskets or air sealed boxes.
• Exterior walls adjacent to fireplaces, tubs, and showersinclude an inside surface air barrier.