California Association of Building Energy Consultants

The 2013 Updated Energy Code Brings Greater Energy Efficiency Requirements

A recap of changes for the new 2013 Energy Code is here. This article shows Mandatory Energy Code Requirements and then the "Package A Prescriptive" Requirements for Climate Zones 11 & 12. Climate Zones 11 & 12 cover the Sacramento, Stockton, Placerville, Granite Bay, Folsom, Rocklin, Roseville, Auburn, Grass Valley, and Marysville areas.

If you need an understanding of the term "Prescriptive Package" there is an older article at this website entitled, "Know the Prescriptive Package Energy Home Design".

The California Energy Commission is under a law to create Zero Net Energy homes by the year 2020. So this year's code is 25-30% stricter. Though some of these changes may not seem like a large step forward there are many other changes underneath that will make energy compliance more costly to achieve.

As always, I am here for questions and comments. If I do not know the answer we will learn together.

Elizabeth (Beth) Smithwick
Certified Energy Analyst

The most up to date standards, 2013 BUILDING ENERGY EFFICIENCY STANDARDS (Title 24, Part 6, and Associated Administrative Regulations in Part 1), are now available online in PDF format [1.6 MB].

New Mandatory Measures


ROOF: Wood Framed Ceilings and Rafter: Minimum R-30 (U-factor 0.031)


Wood Framed: 2x4: minimum R-13 (U-factor = 0.102 maximum)
Wood Framed: 2x6: minimum R-19 (U-factor = 0.074 maximum)

RAISED FLOORS: Wood Framed: Minimum R-19 (U-factor 0.037)

HVAC & Whole House Ventilation

Water Heating

Gas/Propane water heaters must have:

Pipe Insulation must be installed as follows:



No Change: 50% high efficacy/50% low efficacy.

Changed: Recessed light fixtures installed in uninsulated areas to meet mandatory requirements, not just in insulated ceilings.


No Change: Vacancy sensor require for low efficacy fixtures.

Changed: One fixture MUST be high efficacy (no control requirements).

Garages, laundry and utility rooms & closets over 70 SF

Changed: High efficacy light fixture and vacancy sensor required.

Other rooms/Outdoors

No Change: Vacancy sensor or dimmer control of low efficacy fixtures.

No Change: Manual switch, motion sensor and photo-control for low efficacy fixtures.

Solar Ready

For Single Family Subdivisions (10 or more homes):




Climate Zones 11 & 12Prescriptive Package A

Building Envelope Maximum
Minimum Assembly Description
ROOFS/CEILINGS1,2 0.025 R-38 Insulation
Radiant Barrier   Required
Roofing Products  
Low-sloped: SR/TE   NR
Low-sloped: SR/TE   NR
Steep-sloped: SR/TE
(aged solar reflectance/thermal emittance)
  Minimum 0.20 SR & minimum 0.75 TE
2x4 Framing1,2 0.065 R-15+4 or R-13+5
Mass Wall Interior3 0.070 R-13
Mass Wall Exterior3 0.125 R-8.0
Below Grade Interior3 0.070 R-13
Below Grade Exterior3 0.20 R-5.0
Slab Perimeter NR NR
Raised1,2 0.037 R-19
Concrete Raised 0.092 R-8.0
U-factor4 0.32 Dual Pane, Non-Metal, may need spectrally selective glass
Solar Heat Gain Coefficient5 0.25
West Facing Glass   5% Maximum
HVAC SYSTEM: Heating:  
If Gas 78% AUE  
If Heat Pump <65,000 Btu/hr
(Electric Resistance Heat is not Allowed)
7.7 HSPF6  
HVAC SYSTEM: Cooling:  
Central/Electric (All Types) <65,000 Btu/hr 13 SEER  
HERS Requirements:  
Refrigerant Charge Verification   Required
Central Fan Integrated Ventilation System Fan Efficacy Required
Whole House Fan7 Required
DUCTING: R-6.0  
HERS duct testing Required
System shall meet Section 150.1(c)8   See below**


1The U-factors/R-values shown for ceiling, wall and raised floor insulation are for wood-frame construction with insulation between the framing members. For alternative construction assemblies, see Section 150.1 (c)1A, B and C.

2U-factors can be met by cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that results in a U-factor equal to or less than the U-factor shown. R-15+4 means R-15 cavity insulation plus R-4 continuous insulation. Any combination of cavity insulation and/or continuous insulation that results in a U-factor equal to or less than 0.065 is allowed, such as R-13+5.

3Mass wall has a thermal heat capacity greater than or equal to 7.0 Btuh/h-ft2. Below grade "interior" denotes insulation installed on the inside surface of the wall. Below grade "exterior" denotes insulation installed on the outside surface of the wall.

4The installed fenestration products shall meet the requirements of Section 150.1 (c)3.

5The installed fenestration products shall meet the requirements of Section 150.1 (c)4.

6HSPF means "heating seasonal performance factor".

7Only those whole house fans that are listed in the Appliance Efficiency Directory may be installed. Compliance requires installation of one or more WHFs whose total airflow CFM is capable of meeting or exceeding a minimum 2cfm/square foot of conditioned floor are per Section 150.1(C)12.

**Section 150.1(c)8
Domestic Water-heating Systems.

Water-heating systems shall meet the requirements of either A, B, or C, or D.

As always, I am available to discuss the process of meeting the California Energy Code for any building project. Contact me …