2009 Residential Energy Efficiency

Chapter 4 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 a chart form and some additional requirements to be noted are contained in the following bullets:

  • Section 402.2.1 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 or 20% of the total 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.
  • Requires a space that was previously unconditioned to be brought into full compliance if the space is conditioned.

Source: IECC 2009 Table 402.1.1
Insulation and Fenestration Requirements by Component

Climate
Zone

Fenestration
U-Factorb

Skylight
U-Factorb

Fenestration
SHGCb,e

Ceiling
R-Value

Wood Frame
Wall R-Value

1

1.2

0.75

0.3

30

13

2

0.65j

0.75

0.3

30

13

3

0.5j

0.65

0.3

38

13

4 except Marine

0.35

0.6

NR

38

13

5 and Marine 4

0.35

0.6

NR

38

20 or 13+5h

6

0.35

0.6

NR

49

20 or 13+5h

7 and 8

0.35

0.6

NR

49

21


Climate
Zone

Mass Wall
R-Valuei

Floor
R-Value

Basement Wall
R-Valuec

Slab R-Value
& Depthd

Crawl Space
Wall R-Valuec

1

3

13

0

0

0

2

4

13

0

0

0

3

5

19

5/13f

0

5/13

4 except Marine

5

19

10/13

10, 2 ft.

10/13

5 and Marine 4

13

30g

10/13

10, 2 ft.

10/13

6

15

30g

15/19

10, 4 ft.

10/13

7 and 8

19

30g

15/19

10, 4 ft.

10/13

  • a. R-values are minimums, U-factors and SHGC are maximums. R-19 shall be permitted to be compressed into a 2 x 6 cavity such that the R-value is reduced by R-1 or more shall be marked with the compressed batt R-value in addition to the full thickness R-value.
  • b. "15/19" means R-15 continuous insulated sheathing on the interior or exterior of the home or R-19 cavity insulation at the interior of the basement wall. "15/19" shall be permitted to be met with R-13 cavity insulation on the interior of the basement wall plus R-5 continuous insulated sheathing on the interior or exterior of the home. "10/13" means R-10 continuous insulated sheathing on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall.
  • c. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration.
  • d. The first R-value applies to continuous insulation, the second to framing cavity insulation; either insulations meets the requirement.
  • e. R-5 shall be added to the required slab edge R-values for heated slabs. Insulation depth shall be the depth of the footing or 2 feet, whichever is less in Zone 1 through 3 for heated slabs.
  • f. There are no SHGC requirements in the Marine Zone.
  • g. Basement wall insulation is not required in warm-humid locations as defined by Figure 301.1 and Table 301.1.
  • h. Or insulation sufficient to fill the framing cavity, R-19 minimum.
  • i. "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 sheathing of at least R-2.
  • j. The second R-value applies when more than half of the insulation is on the interior of the mass wall.
  • k. For impact reated fenestration complying with Section R301.2.1.2 of the International Residential Code or Section 1608.1.2 of the International Building Code, the maximum U-factor shall be 0.75 in Zone 2 and 0.65 in Zone 3.