Manufactured Housing

Working Group Summary

Joseph Hagerman, DOE
2

MH Working Group Charter

“The purpose of the working group (WG) was to discuss and, if 

possible, reach consensus on a proposed rule for the energy 

efficiency of manufactured homes (MH), as authorized by section 

413 of the Energy Independence and Security Act of 2007 (EISA).”

• The WG was instructed by ASRAC to complete the term sheet 

for a proposed rule by September 30, 2014

– One extension was granted which expired on October 31, 2014.

• The WG convened 6 times over three months to accomplish 

its goal:

– Term Sheet, Appendix A: modifications to IECC to address MH, and a 

list of non-binding recommendations
3

Impacts of Terms Sheet and WG Recommendation

• Preliminary energy savings estimates resulting from the Term 

Sheet...

– Cumulative national energy savings of about 0.7 quads for new 

manufactured homes shipped over a 30 year period. 

• Assumption include 60,000 manufactured homes are shipped annually 

and that each home is operated for 30 years.

• DOE will refine the national energy savings calculation during 

development of the NOPR.

– Realizes 20-30% reduction in today’s manufactured housing annual 

energy consumption.

• Energy savings in a new MH resulting from the Term Sheet would be more 

cost-effective than simply adhering to the 2015 IECC.

• Recommendation: ASRAC accept the term sheet and provide it to the 

Secretary to use as the basis for a Notice of Proposed Rulemaking to the 

maximum extent possible consistent with the Agency's legal obligations.
4

Working Group Recommendations: Term Sheet

Section 2: Applicable Aspects of the 2015 IECC

Recommendation Vote Outcome

Consensus (19-yes; 1-no; 2-

abstain): October 24, 2014

The WG reviewed the 2015 International Energy Conservation 

Code (IECC) for residential buildings for applicability to 

manufactured housing. The WG identified sections of the 2015 

IECC that were not applicable, and modified other sections to 

make them more applicable to manufactured housing.

Considerations: 

The WG reviewed the relevant 

sections of the 2015 IECC. DOE in its 

notice of proposed rulemaking (NOPR) 

process will likely need to review all 

IECC language to ensure no sections 

were missed – to be all inclusive.

Appendix A of the Term 

Sheet contains a line by line 

review of the 2015 IECC and 

makes modifications to 

address the MH industry.
5

Working Group Recommendations: Term Sheet

Section 3: Climate Zones

Recommendation Vote Outcome

Consensus (20-yes; 1-no; 1-

abstain): October 23, 2014

The WG recommends that the energy efficiency standards be 

based on the four climate zones depicted in Figure 3.1 below. 

DOE will determine zoning of Alaska, Hawaii, and US Territories 

when it develops a NOPR.

Consensus (20-yes; 0-no; 2-

abstain): October 24, 2014

The WG recommends using the naming convention of zone 1A, 1B, 

2, and 3.

Figure 3.1 Climate Zone Map

Considerations:

Depending on the outcome of DOE’s 

SHGC analysis, zones 1A and 1B could 

have identical requirements. Some 

WG members expressed that the 

creation of two zones allow for the 

potential for different requirements 

as they felt the regional 

differentiation could help alleviate 

issues of affordability.
6

Working Group Recommendations: Term Sheet

Section 4: Building Thermal Envelope Pathways to Compliance

Recommendation Vote Outcome

Consensus (20-yes; 0-no; 2-

abstain): October 2, 2014

The WG recommends allowing both a prescriptive path option and 

a performance path (Uo) option to ensure improved energy 

efficiency of a manufactured home’s building thermal envelope. 

Both building thermal envelope compliance pathways would also 

include additional mandatory requirements

Considerations: 

The WG voted for 2 paths to provide a 

straightforward method without 

calculations (prescriptive) and a more 

flexible method for housing design that 

includes a Uo calculation (performance). The 

Uo method is the current method of 

compliance for the industry with Housing 

and Urban Development (HUD).
7

Working Group Recommendations: Term Sheet

Section 5: Building Thermal Envelope Requirements: Prescriptive Path Option

Recommendation Vote Outcome

Consensus (20-yes; 1-no; 1-

abstain): October 23, 2014

The WG recommends the prescriptive measures associated with 

the 4 climate zones outlined in Table 5.1 below. These measures 

would apply to all manufactured homes regardless of size.

Climate 

Zone

Ceiling

(R-value)

Wall

(R-value)

Floor

(R-value)

Window

(U-value)

Skylight 

(U-value)

Door

(U-value)

Glazed Fenestration

(SHGC)

1A 30 13 13 0.35 .75 0.40 0.25

1B 30 13 13 0.35 .75 0.40 Pending DOE Analysis*

2 30 21 19 0.35 .55 0.40 Pending DOE Analysis* 

3 38 21 30 0.32 .55 0.40 No Rating

*The WG did not reach consensus on prescriptive specifications for SHGC in climate zones 1B and 2, and 

has recommended that DOE determine these values after further analysis when it develops a NOPR.

Table 5.1 Building Thermal Envelope Prescriptive Requirements

Considerations: 

The WG reviewed the life-cycle cost of several packages of requirements, and 

determined this package to be the most cost-effective. SHGC values are pending DOE 

analysis of the impact of different window position and building orientation 

assumptions than used in the base case model.
8

Working Group Recommendations: Term Sheet

Section 5: Building Thermal Envelope Requirements: Prescriptive Path Option

Recommendation Vote Outcome

Consensus (19-yes; 1-no; 2-

abstain): October 24, 2014

The WG recommends the following footnotes apply to the 

prescriptive requirements listed in the Table 5.1:

1. For conversion between units of length: 1 foot = 304.8 mm.

2. R-values represent minimums; U-values represent maximums.

3. Skylights with SHGC ≤ 0.30 may be excluded from building 

thermal envelope glazed fenestration SHGC requirements.

4. Floor R-values assume R-21 batt + R-14 blanket values to 

account for compression areas in the floor in climate zone 3.

5. The wall R-values column assumes a minimum truss heel 

height of 5.5 inches at the outside face of each exterior wall.

6. Each R-values column reflects the insulation manufacturers’ 

published values. Uniform insulation thickness would not be 

mandatory as long as the required volume of insulation is 

installed with uniform density

Considerations:

Definition of R-values should be reviewed with the Federal 

Trade Commission (FTC) and its guidelines.
9

Working Group Recommendations: Term Sheet

Section 5: Building Thermal Envelope Requirements: Prescriptive Path Option

Recommendation Vote Outcome

Consensus (20-yes; 1-no; 1-

abstain): October 24, 2014

The WG recommends DOE complete further analysis to determine 

U-values for use as an alternative to the R-values listed in Table 

5.1. Under this U-values approach, a manufacturer would need to 

comply with the window, skylight, and door U-values, and the 

glazed fenestration SHGC specifications included in Table 5.1.

Climate 

Zone

Ceiling

(U-value)

Wall

(U-value)

Floor

(U-value)

1A Pending DOE 

Analysis*

Pending DOE 

Analysis*

Pending DOE 

Analysis*

1B Pending DOE 

Analysis*

Pending DOE 

Analysis*

Pending DOE 

Analysis*

2 Pending DOE 

Analysis*

Pending DOE 

Analysis*

Pending DOE 

Analysis*

3 Pending DOE 

Analysis*

Pending DOE 

Analysis*

Pending DOE 

Analysis*

Table 5.2 U-Value Alternative for Ceiling, Wall, and Floor

*The WG did not reach consensus on the U-values in Table 5.2 and 

has recommended DOE determine these values after further 

analysis when it develops a NOPR.

Considerations:

The WG did not have enough time 

to reach a consensus on these 

values. Therefore, DOE needs to 

determine the R-value to U-value 

conversion for the NOPR, which 

may be different than the IECC 

equivalents. The conversion is 

dependent on manufactured 

home construction assumptions.
10

Working Group Recommendations: Term Sheet

Section 6: Building Thermal Envelope Requirements: Uo Performance Path Option

Recommendation Vote Outcome

Consensus (19-yes; 1-no; 2-

abstain): October 24, 2014

The WG recommends the Uo values in Table 6.1. The SHGC 

requirement shall be met in addition to Uo. An area weighted 

average SHGC shall satisfy the glazed fenestration SHGC 

requirements of Table 5.1. 

Table 6.1 Uo Values for Performance Path

Climate Zone Single-Section Uo Multi-Section Uo

1A 0.087 0.084

1B 0.087 0.084

2 0.070 0.068

3 0.059 0.056

Consensus (20-yes; 0-no; 2-

abstain): October 24, 2014

The WG recommends that the calculation of Uo follow the Battelle 

method. The Battelle method produces an area-weighted average 

overall U-value for a home based on the thermal qualities and 

areas of material assemblies used in the home’s construction.

Consensus (20-yes; 1-no; 1-

abstain): October 23, 2014

Considerations:

More members supported having separate Uo values for 

different sized homes than one Uo value for all homes. This 

approach does give a less stringent requirement for single- section homes, which are the typical option for low-income 

buyers – some members of the WG felt that this approach also 

helped address affordability.
11

Working Group Recommendations: Term Sheet

Section 7: Other Mandatory Requirements – Envelope Sealing

Recommendation Vote Outcome

Consensus (15-yes; 2-no; 5-

abstain): September 23, 2014

To provide envelope tightness of 5 air changes per hour (ACH) 

when depressurized to 50 Pascals (Pa), the WG recommends that 

all manufactured homes would be required to ensure that:

1) A continuous air barrier is established upon installation of all 

building thermal envelope (i.e., ceiling, walls, doors, and 

floor) opaque components

2) Mating line surfaces (i.e., floor, exterior walls, and ceiling) are 

equipped with a continuous, durable gasket.

3) Gaps and penetrations in the ceilings, floors, and exterior 

surfaces of walls would be sealed with caulk, foam or gasket, 

or other suitable material. 

4) Rough openings around windows and exterior doors are 

sealed with caulk or foam.

Considerations:

DOE should conduct testing after the compliance date of 

standards to assess the effectiveness of these visual inspection 

requirements. Because of a lack of data/cost on this issue, the 

WG did not recommend direct testing of envelope sealing.
12

Working Group Recommendations: Term Sheet

Section 7: Other Mandatory Requirements – Envelope Sealing (continued)

Recommendation Vote Outcome

Consensus (15-yes; 2-no; 5-

abstain): September 23, 2014

To provide envelope tightness of 5 air changes per hour (ACH) 

when depressurized to 50 Pascals (Pa), the WG recommends that 

all manufactured homes would be required to ensure that (cont.):

5) Attic access panels and drop-down stairs are equipped with 

gaskets (i.e., not caulked) to produce a continuous air seal.

6) Duct system register boots that penetrate the building 

thermal envelope and/or air infiltration barrier are sealed to 

the air barrier or interior finish materials.

7) Sealing methods between dissimilar materials allow for 

differential expansion and contraction

Considerations:

DOE should conduct testing after the compliance date of 

standards to assess the effectiveness of these visual inspection 

requirements. Because of a lack of data/cost on this issue, The 

WG did not recommend direct testing of envelope sealing.
13

Working Group Recommendations: Term Sheet

Section 7: Other Mandatory Requirements – Duct Sealing and Hot Water Pipe Insulation

Recommendation Vote Outcome

Consensus (19-yes; 0-no; 3-

abstain): September 22, 2014

The WG recommends that duct leakage must be no greater than 4 

cubic feet per minute (CFM) per 100 square feet of floor area at a 

25 Pa test pressure. 

Consensus (17-yes; 0-no; 5-

abstain): September 23, 2014

The WG recommends that all hot water pipes outside conditioned 

space would be required to be insulated to at least R-3. In 

addition, all hot water pipes from a water heater to a distribution 

manifold would be required to be insulated to at least R-3. 

Considerations:

The WG assumed duct leakage testing would be needed 

for all homes. Industry perceives the recall risk as too 

great if they ship a non-compliant home.
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Back-up Slides

• Non-binding Recommendations

• WG membership
15

Non-binding Working Group Recommendations (1)

Other Recommendations Outside the Scope of the Working Group

Recommendation

The WG recommends that DOE charter a new working group through ASRAC to develop 

recommendations regarding certification-testing and enforcement. [DOE SUPPORTS]

The WG recommends that DOE modify the REScheck software application to specifically address 

manufactured housing. The WG observed that both inputs and calculation assumptions (e.g., the 

siting orientation of the home) would require modification to account for the factory construction 

of manufactured homes. The modified application also would provide recommendations for 

equipment sizing. [DOE SUPPORTS GIVEN FUNDING]

The WG recommends that DOE consider development of a duct sizing tool, potentially based on the 

Air Conditioning Contractors of America (ACCA) Manual D. [NO COMMENT]

The WG discussed and made notes on other recommendations, issues, concerns, and 

opportunities that DOE should consider as it begins to regulate the industry. All these topics are 

not binding to the terms sheet.
16

Non-binding Working Group Recommendations (2)

Other Recommendations Outside the Scope of the Working Group

Recommendation

The WG has three recommendations involving building thermal envelope sealing: [NO COMMENT]

1) DOE conduct testing to confirm an average ACH of 5 is achieved in practice with the 7 visual 

inspection envelope sealing requirements listed in section 7. This testing could inform future 

decisions regarding building thermal envelope sealing.

2) DOE conduct a WUFI analysis to assess potential moisture concerns of the proposed package 

on exterior walls. This analysis could inform future decisions and regulations regarding building 

thermal envelope sealing. 

3) DOE consider approaches to address a scenario in which an exterior surface of a wall cannot 

be sealed, such as the case in which the exterior sheathing is also the structural sheathing, and 

the resulting impact to the recommendations from section 7. 

The WG recommends that DOE consider labeling approaches that provide (1) voluntary labeling for 

whole-house performance information, (2) heating/cooling equipment sizing parameters capable of 

servicing a home with the highest expected heating and cooling load, and (3) additional 

information on building components and equipment. [DOE SHOULD REVIEW THIS WITH THE 

APPROPRIATE PARTIES]

The WG recommends DOE consider an education program on energy efficiency for potential 

owners of manufactured housing. [NO COMMENT]
17

Non-binding Working Group Recommendations (3)

Other Recommendations Outside the Scope of the Working Group

Recommendation

The WG recommends DOE consider an education program on non-energy benefits for potential 

owners of manufactured housing including indoor air quality, comfort, and durability. [NO 

COMMENT]

The WG recommends DOE consider certain revisions to the HUD regulations at Subpart F of 24 CFR 

Part 3280. DOE should discuss these recommendations with HUD to address duplications and 

inconsistencies between the current 24 CFR Part 3280 and DOE’s eventual NOPR. [NO COMMENT]

Considerations:

DOE will take into consideration these recommendations.

The WG recommends that DOE consider government supports/grants/subsidies/etc. for energy 

efficiency, and that DOE consider increasing DOE R&D funding to a level commensurate with the role 

of manufactured housing in the nation’s housing mix. [NO COMMENT]
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Working Group Members

Name

Joseph Hagerman

John Caskey

Bert Kessler

David Tompos

Emanuel Levy

Eric Lacey

Ishbel Dickens

Keith Dennis

Lois Starkey

Lowell Ungar

Manuel Santana

Affiliation

Department of Energy

ASRAC, National Electrical Manufacturers 

Association

Palm Harbor Homes, Inc.

NTA, Inc.

System Building Research Alliance

Responsible Energy Codes Alliance

National Manufactured Home Owners Association 

(NMHOA)

National Rural Electric Cooperative Association

Manufactured Housing Institute

American Council for an Energy-Efficient Economy

Cavco Industries Mark Ezzo

Name

Mark Weiss

Michael Lubliner

Michael Wade

Peter Schneider

Richard Hanger

Richard Potts

Rob Luter

Robin Roy

Scott Drake

Stacey Epperson

Clayton Homes, Inc.

Affiliation

Manufactured Housing Association for 

Regulatory Reform

Washington State University Extension 

Energy Program

Cavalier Home Builders

Efficiency Vermont

Housing Technology and Standards

Virginia Department of Housing and 

Community Development

Lippert Components, Inc.

Natural Resources Defense Council

East Kentucky Power Cooperative

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