# Presentation: 719668

## The 2006 IECC—Will it Change Your Life for the Better?

- Z. Todd Taylor
- Pacific Northwest National Laboratory
- Building Energy Codes Program
- U.S. Department of Energy

## Summary

- The 2006 IECC is much simpler and easier to understand, comply with, and enforce
- But its many differences with respect to the 2003 IECC may lead to some confusion

## PART 1How the 2006 IECC Makes Life Easier

- (a brief review)

## Making life easier

- Homogeneity across building types
- Homogeneity across construction types
- Homogeneity across building designs
- Homogeneity within jurisdictions
- Simplicity and memorizability

## Making life easier—homogeneity across building types

- Single family and multifamily buildings use exactly the same requirements

## Making life easier—homogeneity across construction types

- New construction and addition/remodel use the same requirements

## Making life easier—homogeneity across building designs

- All sizes, shapes, and glazing areas use the same requirements
- No dependency on window-wall ratio
- No dependency on window-floor ratio
- (Exception:  performance path)
- Enforcement easier
- Plan review frequently unnecessary
- Inspections require no measurements
- Fewer irrational behaviors
- Large buildings no longer comply with less insulation
- High ceilings (10-ft walls) no longer comply with less insulation
- Starter homes (small window areas) and apartments no longer have unreasonably inefficient envelopes

## Making life easier—homogeneity within jurisdictions

- Requirements never vary within county boundaries

## Making life easier—homogeneity within jurisdictions

**Making life easier—homogeneity within jurisdictions**

***The old way (2003 and prior)***

- Dashed lines represent HDD-based
- zones – Note that ***no*** zone is
- homogenous

## Making life easier—homogeneity within jurisdictions

***The new way (2004 and later)***

- Zones are defined entirely by
- county boundaries—*every*
- county is homogenous

## Making life easier—homogeneity within jurisdictions

**Table 402.1.1****Insulation and Fenestration Requirements by Component**

## Making life easier—simplicity and memorizability

- Primary requirements expressed as R-values, not U-factors
- Rules of thumb are meaningful and easy to remember
- Last-minute construction changes don’t torpedo those rules of thumb
- REScheck can always be made to hit exactly “0% better”  
- Performance path greatly improved

## PART 2Threats to the Easy Life

- or
- What questions or problems might you or your users encounter when you adopt the 2006 IECC?

## Threats to the easy life--overview

- Compliance paths
- Hard limits
- IECC/IRC differences
- Climate zones
- Opaque doors
- Duct insulation
- U-factors

- Below-grade walls
- Heated slabs
- Prescriptive exemptions/allowances
- Certificate
- Mass walls
- Performance path

- Mark your code books!

## How many are there?
Two
Prescriptive
Performance
Three
Prescriptive
UA
Performance
Four
Prescriptive R-value
Prescriptive U-factor
UA
Performance

- Two
- Prescriptive
- Performance
- Three
- Prescriptive
- UA
- Performance
- Four
- Prescriptive R-value
- Prescriptive U-factor
- UA
- Performance

**Potential issue—compliance paths**

## How many are there?
Two
Prescriptive
R-value
U-factor
UA
Performance

- Two
- Prescriptive
- R-value
- U-factor
- UA
- Performance

**Potential issue—compliance paths**

## Potential issue—compliance paths

## Potential issue—hard limits

- Formally, these are “mandatory” minimums (or maximums)
- AKA, “trade-off limits”
- Section 402.6
- Fenestration U-factor ≤ 0.48 (zones 4-5)
- Fenestration U-factor ≤ 0.40 (zones 6-8)
- Skylight U-factor ≤ 0.75 (zones 4-8)
- Fenestration SHGC ≤ 0.5 (zones 1-3)
- 	*NOTE:  These are all area-weighted averages*

## Potential issue—hard limits

| Zone | Prescriptive | Mandatory
(hard limits) |
| --- | --- | --- |
| 1 | SHGC ≤ 0.4 | SHGC ≤ 0.5 |
| 2 | SHGC ≤ 0.4 | SHGC ≤ 0.5 |
| 3
(except Marine) | SHGC ≤ 0.4 | SHGC ≤ 0.5 |
| 4 except Marine | Uvert ≤ 0.40
Uskylight ≤ 0.60 | Uvert ≤ 0.48
Uskylight ≤ 0.75 |
| 5 and
Marine 4 | Uvert ≤ 0.35
Uskylight ≤ 0.60 | Uvert ≤ 0.48
Uskylight ≤ 0.75 |
| 6 | Uvert ≤ 0.35
Uskylight ≤ 0.60 | Uvert ≤ 0.40
Uskylight ≤ 0.75 |
| 7 & 8 | Uvert ≤ 0.35
Uskylight ≤ 0.60 | Uvert ≤ 0.40
Uskylight ≤ 0.75 |

## Potential issue—IRC differences

- Hard limits are different for U-factors, nonexistent for SHGC
- Minor mass wall differences
- Covers residential only, excludes most apartments
- Has no performance path
- (References IECC)

## Potential issue—climate zones

- New zones are better at capturing cooling drivers
- But...

## Climate zones

## Climate zones represent multiple climate drivers

## Climate zones represent multiple climate drivers

## Climate zones represent multiple climate drivers

## Climate zones represent multiple climate drivers

## Potential issue—climate zones

- New zones are better at capturing climate drivers
- But...
- Cities and towns have new zones

## Mapping from HDD-based Zones to New Zones(each cell shows the number of cities)

|  | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 799 | 250 | 0 | 0 | 0 | 0 | 0 | 0 |
| 2 | 0 | 1481 | 0 | 0 | 0 | 0 | 0 | 0 |
| 3 | 0 | 2756 | 227 | 0 | 0 | 0 | 0 | 0 |
| 4 | 0 | 5305 | 2052 | 0 | 0 | 0 | 0 | 0 |
| 5 | 0 | 1031 | 6410 | 0 | 0 | 0 | 0 | 0 |
| 6 | 0 | 0 | 13405 | 0 | 0 | 0 | 0 | 0 |
| 7 | 0 | 0 | 10764 | 1299 | 0 | 0 | 0 | 0 |
| 8 | 0 | 0 | 3768 | 7419 | 0 | 0 | 0 | 0 |
| 9 | 0 | 0 | 317 | 14473 | 0 | 0 | 0 | 0 |
| 10 | 0 | 0 | 39 | 15370 | 154 | 0 | 0 | 0 |
| 11 | 0 | 0 | 0 | 12539 | 2137 | 0 | 0 | 0 |
| 12 | 0 | 0 | 0 | 659 | 15469 | 56 | 0 | 0 |
| 13 | 0 | 0 | 0 | 0 | 12044 | 0 | 0 | 0 |
| 14 | 0 | 0 | 0 | 0 | 9426 | 427 | 0 | 0 |
| 15 | 0 | 0 | 0 | 0 | 1927 | 12744 | 62 | 0 |
| 16 | 0 | 0 | 0 | 0 | 0 | 2631 | 350 | 0 |
| 17 | 0 | 0 | 0 | 0 | 0 | 125 | 2605 | 16 |
| 18 | 0 | 0 | 0 | 0 | 0 | 0 | 11 | 113 |
| 19 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 163 |

- 2006 IECC Zone Number

- Old IECC Zone Number

## Potential issue—climate zones

- New zones are better at capturing climate drivers
- But...
- Cities and towns have new zones
- Within-county homogeneity can misrepresent extreme microclimates

## Potential issue—within-county homogeneity and elevation

## Potential issue—within-county homogeneity and elevation

## Potential issue—within-county homogeneity and elevation

## Potential issue—within-county homogeneity and elevation

## Potential issue—within-county homogeneity and elevation

## Potential issue—within-county homogeneity and elevation

## Potential issue—opaque doors

- Are opaque doors regulated?
- Where are the requirements?

**Table 402.1.1****Insulation and Fenestration Requirements by Component**

## Potential issue—opaque doors

- Are opaque doors regulated?
- Where are the requirements?
- 	“Fenestration” includes all doors, whether glazed, opaque, or combination

## Potential issue—duct insulation

- How can the R-8 duct insulation requirement be traded off?
- 				**It can’t.**
**	**(Duct insulation is a*** mandatory*** requirement.)

## Potential issue—U-factors

- Overheard:  “The U-factors in Table 402.1.3 don’t match the R-values in Table 402.1.1”

## Potential issue—U-factors

## Potential issue—U-factors

- Overheard:  “The U-factors in Table 402.1.3 don’t match the R-values in Table 402.1.1”
- Response:
- Oh, yes they do!
- That’s not surprising and it doesn’t matter
- The U-factor table uses conservative assumptions (e.g., eave compression)
- Your building probably really is different from the code’s assumptions

## Potential issue—below-grade walls

- The Zone-3 loophole:
- A floor over an ***unheated*** basement requires R-19
- Walls of a ***heated*** basement require R-0
- So...
- Declare the basement heated (or really heat it)
- And you can eliminate the insulation!

## Potential issue—heated slabs

**Potential issue—heated slabs**

- The R-0 conundrum in Zones 1-3:
- Unheated slabs require 0 feet of R-0 insulation
- Heated slabs require that R-5 be added to the unheated requirement
- So...
- The requirement is 0 feet of R-5 insulation?

## Potential issue—prescriptive exemptions and special allowances

- Exemptions & allowances:
- Where R-38 ceilings required, R-30 with raised trusses will suffice (ditto for R-49/38)
- Where >R-30 ceilings required, R-30 will suffice if the higher value would require larger structural members (500-ft2 limit)
- Up to 15 ft2 of glazing may be exempted from U-factor and SHGC requirements
- One opaque door is exempted from the U-factor requirement

## Potential issue—prescriptive exemptions and allowances

- Intent of R-value allowances was to give a little flexibility to the otherwise static R-value table (402.1.1)
- Not needed when using the U-factor table
- However...
- ICC has interpreted these to apply to the U-factor table as well
- Which leads to logic issues and lesser efficiency
- Opaque door language (“is exempted” rather than “shall be permitted to be exempted”)—one could infer that taking the exemption is mandatory

## Potential issue—certificate

- Code says put certificate “on or in the electrical distribution panel”
- Some worry about violating electrical codes (Section 408.4 of the 2002 NEC)
- Code-change proposals in the works:
- EC32 clarifies that the certificate should not cover or obstruct other required labels or signs
- EC33 eliminates the certificate altogether

## Potential issue—mass walls

- ISSUE:
- Mass wall R-value can be lower than frame wall R-value ***if ******≥ 50% of the “required R-value is on the exterior of, or integral to, the wall”***
- Exceptions in zones 1-3 provide a mid-way ***“added R-value”*** for walls that don’t meet the mass placement requirement
- QUESTIONS:
- What “required R-value”?  (Should read “proposed R-value”?)
- What does “added” mean?

## Potential issue—mass walls

**Table 402.1.1****Insulation and Fenestration Requirements by Component**

- Section 402.2.3 adds:
- 	Can’t use mass-wall R-value unless the mass is inside
- 	(or integral with) the insulation.
- 	Except that, for zones 1-3:
- 	If mass is outside, may use R4, R6, and R8 instead of R13.

## Potential issue—mass walls

| Zone | Frame wall R-value | Mass wall R-value (mass inside/outside insulation) |
| --- | --- | --- |
| 1 | 13 | 3 / 4 |
| 2 | 13 | 4 / 6 |
| 3 | 13 | 5 / 8 |
| 4 | 13 | 5 / Frame-R |
| 5 | 19 or 13+5 | 13 / Frame-R |
| ... | ... | ... |

- What it really means:

## Potential issue—performance path

- The only way to do HVAC trade-offs (so it’s likely to get used more often)
- Baseline is U-factor (Table 402.1.3), not R-value (Table 402.1.1)
- Mandatory requirements still apply
- Duct insulation R-value ≥ 8
- Hard limits on glazing U/SHGC
- Taping/caulking for air tightness
- Metric of comparison is ***energy cost*** (unless local jurisdiction requires ***site energy***)

## Potential issue—performance path

- Calculation procedure must be software
- Comparing each “proposed design” against a “standard reference design”
- Conforming to the code’s specific rules for comparing the two designs
- Documented as to its accuracy and correctness
- Having at least a specified minimum set of capabilities
- Producing a specified suite of output reports
- Other tools permitted if approved by official
- (e.g., limited scope or locally-relevant application)

## Differences w.r.t. prescriptive path
Outside scope of prescriptive path
Glazing area (above 18% CFA)
Glazing orientation
Credit/penalty for tested air-tightness
Mechanical ventilation
Features never in standard reference design
Skylights
Electric Furnace
Sunrooms
The “value” of an envelope change is different (usually less)

- Outside scope of prescriptive path
- Glazing area (above 18% CFA)
- Glazing orientation
- Credit/penalty for tested air-tightness
- Mechanical ventilation
- Features never in standard reference design
- Skylights
- Electric Furnace
- Sunrooms
- The “value” of an envelope change is different (usually less)

**Potential issue—performance path**

***Might appear to be***
***built-in penalties***
***for some homes***

***Might appear to be***
***built-in free-riders***
***for some homes***

## Things that might confuse—performance path vs UA path

## Potential issue—performance path vs UA path

- The UA “slope” is similar between the 2003 IECC and the 2006 IECC

**Potential issue—performance path vs UA path**

- But the performance slope is generally shallower than the UA slope

## PART 3What About Energy Efficiency?

## What about energy efficiency?

- 2006 IECC efficiency increases
- Multifamily homes
- Homes with average to below-average glazing percentages
- Duct insulation (always R8)
- Air handler must be sealed
- 2006 IECC efficiency reductions
- Homes with above-average glazing percentages
- Homes in rural, high-elevation locations

## Questions and Discussion