2006 Residential Energy Efficiency

Unlike in the 2000 IECC and 2003 IECC, there is only one form of prescriptive requirements found in the Code for walls, ceilings, floors, windows and doors. Chapter 4 also covers new construction, additions, remodeling, window replacement, and repairs of specific buildings. Existing installations are exempted, as are portions of buildings not altered when additions, remodeling, window replacement, or repairs take place. Historic residences are also exempted from meeting the requirements of the Code. The table below summarizes the prescriptive paths in chart form and some additional requirements to be noted in the following bullets:

  • Section 402.2.2 may be used to allow for less insulation in the ceiling without attic space when the requirements are above R - 30 only when the floor area is less than 500 square feet of conditioned space.
  • Where some or all of an existing fenestration unit is replaced with a new fenestration product, including sash and glazing, the replacement fenestration unit shall meet the building thermal envelope requirements.

Source: IECC 2006 Table 402.1.1
Insulation and Fenestration Requirements by Component

Climate
Zone

Fenestration
U-Factor

Skylight
U-Factor

Fenestration
SHGC

Ceiling
R-Value

Wood Frame
Wall R-Value

1

1.2

0.75

0.4

30

13

2

0.75

0.75

0.4

30

13

3

0.65

0.65

NR

38

13

4 except Marine

0.4

0.6

NR

38

13

5 and Marine 4

0.35

0.6

NR

38

19 or 13+5

6

0.35

0.6

NR

49

19 or 13+5

7 and 8

0.35

0.6

NR

49

21


Climate
Zone

Mass Wall
R-Value

Floor
R-Value

Basement Wall
R-Value

Slab R-Value
& Depth

Crawl Space
Wall R-Value

1

3

13

0

0

0

2

4

13

0

0

0

3

5

19

0

0

5/13

4 except Marine

5

19

10/13

10, 2 ft.

10/13

5 and Marine 4

13

30

10/13

10, 2 ft.

10/13

6

15

30

10/13

10, 4 ft.

10/13

7 and 8

19

30

10/13

10, 4 ft.

10/13

  • R-values are minimums, U-factors and SHGC are maximums. R-19 shall be permitted to be compressed into a 2 x 6 cavity.
  • The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration.
  • The first R-value applies to continuous insulation, the second to framing cavity insulation; either insulations meets the requirement.
  • R-5 shall be added to the required slab edge R-values for heated slabs.
  • There are no SHGC requirements in the Marine Zone.
  • Or insulation sufficient to fill the framing cavity, R-19 minimum.
  • "13+5" mean R-13 cavity insulation plus R-5 insulated sheathing. 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 insulation.