retrofitting manufactured homes for improved energy … · 2 – retrofitting manufactured homes...

J U N E 2 0 1 1

Retrofitting Manufactured Homes for Improved Energy Efficiency

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Prepared by

Eric Cody

for

The National Rural Electric Cooperative AssociationCooperative Research Network

4301 Wilson BoulevardArlington, Virginia 22203-1860

Retrofitting Manufactured Homesfor Improved Energy Efficiency

www.cooperative.com/crn

The National Rural Electric Cooperative AssociationThe National Rural Electric Cooperative Association (NRECA), founded in 1942, is the national service organization supportingmore than 900 electric cooperatives and public power districts in 47 states. Electric cooperatives own and operate more than 42 percent of the distribution lines in the nation and provide power to 40 million people (12 percent of the population).

NRECA’s Cooperative Research Network (CRN) harnesses research and development to benefit its electric co-op members infour key ways:

• Improve productivity• Control costs• Increase service excellence• Keep pace with emerging technologies

CRN strives to deliver new products and services best suited to the particular needs of electric co-ops. CRN communicates withits members through its Web site (www.cooperative.com/crn), online and printed reports, newsletters, Web conferences, andseminars.

In addition, CRN staff present at several annual events, including NRECA’s TechAdvantage Conference & Expo, theNRECA/Touchstone Energy “Connect” marketing conference, and Touchstone Energy’s New & Emerging Technologies (NET)Conference. For more information about these events and CRN’s participation, visit the Conferences & Training section ofwww.cooperative.com. For questions about CRN, call 703.907.5843.

© Retrofitting Manufactured Homes for Improved Energy EfficiencyCopyright © 2011 by the National Rural Electric Cooperative Association.Reproduction in whole or in part strictly prohibited without prior written approval of the National Rural Electric CooperativeAssociation, except that reasonable portions may be reproduced or quoted as part of a review or other story about this publication.

Legal NoticeThis work contains findings that are general in nature. Readers are reminded to perform due diligence in applying these findings to their specific needs as it is not possible for NRECA to have sufficient understanding of any specific situation toensure applicability of the findings in all cases.

Neither the authors nor NRECA assumes liability for how readers may use, interpret, or apply the information, analysis, templates, and guidance herein or with respect to the use of, or damages resulting from the use of, any information, apparatus, method, or process contained herein. In addition, the authors and NRECA make no warranty or representation that the use of these contents does not infringe on privately held rights.

This work product constitutes the intellectual property of NRECA and its suppliers, as the case may be, and containsConfidential Information. As such, this work product must be handled in accordance with the CRN Policy Statement onConfidential Information.

Questions

Brian Sloboda, Senior Program [email protected]

NRECA MEMBERS ONLY

Contents – i i i

contents

Acknowledgements vi

About the Author vii

Note from the Author viii

Executive Summary ix

Retrofitting Manufactured Homes for Improved Energy Efficiency 1

The View from Ten Thousand Feet 1

Unique Challenges of Manufactured Housing 5

Creating an Energy Efficiency Retrofit Program that Works 10

Management Checklist: A Place to Begin 15

Conclusions 16

Additional Information 16

iv – I l lustrat ions

i l lustrat ions

1 Typical Double-Wide Manufactured Home 22 Energy Sources for Heating and Cooling in Manufactured Homes vs. 3

All Housing Types3 How Surveyed Electric Cooperatives Rated the Importance of 4

Improving the Energy Efficiency of Manufactured Housing in Their Service Territories

4 Most Commonly Reported Problems in Serving Members in 6Manufactured Housing

5 Common Factors Contributing to Manufactured Housing Energy 7Efficiency Problems

6 Air Gap in “Marriage Wall” 77 Badly Compromised Crossover Duct 78 Residential Energy Efficiency/Renewable Energy Programs Offered by 11

Electric Co-ops9 Proactive Model for Manufactured Housing Retrofits 12

FIGURE PAGE

Tables – v

tables

1 Checklist of Retrofit Measures Likely to be Cost-Effective in 9Manufactured Homes

TABLE PAGE

vi – Acknowledgements

acknowledgements

The author acknowledges the following individ-uals and electric cooperatives for their critical in-puts and feedback on this report: Tony Wassonof Central Florida Electric Cooperative; ManuelaHeyn of Gulf Coast Electric Cooperative; KevinShort of Anza Electric Cooperative; Staci Behnke,Mindy Morrow, and Randy Nolan of Valley Elec-tric Cooperative; Jon Cullimore of Coosa Valley

Electric Cooperative; Brian Hefner of CoastalElectric Cooperative; and Heidi Smith of Tide-land Electric Membership Corporation. Thanksalso to Bob Scott of the National Association ofState Community Service Programs for sharinghis insights into weatherization assistance formanufactured homes.

Eric Cody is a consultant who has worked with NRECA, CRN, and individual electric cooperatives for more than a decade on technology planning and management issues.He has 30 years of experience with electric utilities, including a dozen years as a vice president of several New England Electric System companies (now part of National

Grid USA). During his utility career, Mr. Cody has managed energy efficiency and demand reduction pilot programs and full-scale programevaluations, among other responsibilities. Heholds a bachelor’s degree from Amherst Collegeand a master’s degree from Harvard University,where he specialized in energy planning andpolicy analysis.

About the Author – v i i

about the author

Note f rom the Author – v i i i

note f rom the author

During the course of this research, it became evident that, while a number of legislative billsintended to address the problem of energy effi-ciency in manufactured homes have been filedin Congress, no currently pending bill appearsto have a favorable chance of becoming law.While the energy efficiency standards in the current HUD Code are to be strengthened

further by the end of 2011, an expanded federal role in enabling energy efficiency retrofit financing is unlikely, hence this subject is not discussed in the report. The author hasconcluded that electric cooperatives needing to address the challenges described in this report will not be able to count on meaningfulfederal action.

Higher-than-necessary electricity use by customers living in manufactured housing

units is a chronic problem for many electric cooperatives across the country. The cost toheat and cool manufactured homes with leakyair ducts, ill-suited or poorly sized HVAC systems, shoddy construction, or deterioratedbuilding components often results in a largershare of high-bill complaints from this housingsegment than from “site-built” homes, even for co-ops that have far more of the latter ontheir systems. In fact, some electric cooperativesreport customers living in manufactured hous-ing who see monthly electric bills as high as$1,000, despite the units’ relatively small squarefootage. Retrofitting manufactured housingunits for improved energy effi ciency is equallyproblematic. Many manufactured home ownerslack the financial means to implement conser-vation measures recommended by energy au-dits, and landlords in rental situations often are

unwilling to make the needed investment ingreater efficiency.

Electric cooperatives as a group are likely tobe impacted more directly by these challengesthan other utilities because they serve manyrural and lower-income areas. Over the years,electric co-ops have tried a variety of programsand approaches to address this issue but mosthave met with only limited success. New programs, policies, and practices are availableto address this problem directly or indirectly,including incentives to replace electric furnaceswith heat pumps, retrofit loan financing pro-grams and, for new manufactured housingunits, the tightening of federal manufactured-home construction standards (the so-calledHUD Code) currently underway. This reportevaluates what has worked, what has not, and shares best-practice approaches electric cooperatives can apply proactively to gain traction in addressing this critical challenge.

Executive Summary – ix

executive summary

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In This Report:

Retrof i t t ing Manufactured Homes for Improved Energy Ef f iciency – 1

The View from Ten Thousand Feet

Unique Challenges of Manufactured Housing

Creating an Energy Efficiency Retrofit Program that Works

Management Checklist: A Place to Begin

Conclusions

Additional Information

This report lists characteristics of manufacturedhousing stock, explains why energy efficiencyretrofit programs must be tailored to the uniqueneeds of manufactured homes, and suggests aprocess-oriented approach that electric coopera-tives can adopt to manage the manufacturedhome efficiency challenge more proactively.What this report does not provide is a “silver

bullet” that can be used by all electric co-ops to address the problem. Because manufacturedhome energy losses manifest themselves in dif-ferent ways due to the unique, local characteris-tics of each electric cooperative’s service territory,there is no one-size-fits-all solution. The prob-lem is real and the answer lies in the process.

Retrofitting Manufactured Homesfor Improved Energy Efficiency

The View from TenThousand Feet

“In February 2009, a woman in her nineties re-ceived an electric bill from Tideland for $903.52(two months earlier, the bill had been $789.96).During a follow-up energy audit, it was foundthat her double-wide home’s crossover ducthad fallen apart and most of the woman’s heatwas escaping underneath the home. Tidelandcontacted a group of volunteers, who spentapproximately six hours at the home one Sat-urday weatherizing and making repairs to the

floor insulation. A local HVAC repairman do-nated his time and materials to replace theductwork. Post-weatherization, the member’selectric bills averaged $132.85 a month untilher death in April 2010. The home has sincebeen reoccupied and the bills average $93.13 a month. So the repairs didn’t provide a band-aid; they provided a cure. I have dozens ofsuch stories. We just need some basic funds toget these types of problems repaired.”1

1 Source: Heidi Smith, Manager of Economic Development, Marketing & Corporate Communications, Tideland Electric Membership Cooperative (EMC), March 2011.

In Their Own Words: Tideland EMC’s Manufactured Home Problem

WHAT QUALIFIES AS MANUFACTUREDHOUSING?For the purposes of this report, manufacturedhousing refers to a home built in a factory andcomplying with the HUD Manufactured HomeConstruction and Safety Standards (commonlyknown as the ‘HUD Code’), which first took effect in 1976.2 Factory-built homes that predatethe HUD Code also are considered to be manu-factured housing if they sit on a permanentfoundation or chassis and are never movedfrom their initial installation site. Not surpris-ingly, post-1976 manufactured homes typicallyare more energy efficient than those built beforethe HUD Code took effect.Manufactured homes come in several config-

urations: single-, double-, and triple-wide. Ac-cording to NRECA’s 2011 Manufactured HousingSurvey, nearly three-fourths of those served byparticipating electric cooperatives are single- ordouble-wides.3 Figure 1 shows a typical double-wide home. One key difference between thesetwo types is that a crossover duct is used toprovide air flow between the sections that makeup a double-wide (or triple-wide). This particu-lar duct often is found to be a major air leakage

2 – Retrof i t t ing Manufactured Homes for Improved Energy Ef f iciency

culprit that contributes significantly to loss of energy efficiency, as discussed later in this report.

HOW DO MANUFACTURED HOMES DIFFERFROM “SITE-BUILT” HOMES?The ways in which manufactured homes are designed, built, installed, and operated help toexplain why their levels of energy performancecan be much lower than those seen in site-builthomes. In theory, a home built in a factory canbe designed and constructed to finer tolerances,and so the building envelope can be madetighter. However, this generally is not reflectedin the nation’s installed manufactured housingstock for various reasons, among them:

• Lower-quality, less energy-efficient, or lessdurable materials may be used in construction.

• Design specifications may not be met, e.g.,2x4 wall studs may be called for but 2x2studs are found later, when the wall isopened, reducing by half the amount of insulation installed.

• The manufactured unit must be transportedto the site, and movement can disrupt theintegrity of its original construction.

• While some manufactured units sit on foun-dations, many are placed on jack stands orblocks concealed by skirting around the baseof the unit. This allows air to flowunderneath the home and permits invasionby rodents and other animals.

• Joining of multiple sections once on site tocreate a double- or triple-wide home may notbe done properly, leaving an air and moisturegap in the “marriage wall.”

• Siting of the home may not be optimal withrespect to solar exposure for energy-efficientoperation in either summer or winter.

• Some energy-efficient appliances, includingthe highest efficiency-rated Marathon hotwater tank, will not fit in the water-heatercloset of many manufactured homes.

FIGURE 1: Typical Double-Wide Manufactured Home (Photo courtesy of Gulf Coast Electric Cooperative).

2 HUD Code-compliant manufactured homes (post-1976) display a certification label and data plate. 3 NRECA Market Research Services. “2011 Manufactured Housing Study Survey Results.” February 2011. According

to electric co-ops that responded to NRECA’s survey, mobile homes—which are beyond the scope of this report—account for a fourth of manufactured homes served.

• Many manufactured homes originally wereintended for seasonal use only, resulting inthe use of substandard HVAC systems andlow levels of insulation.Their current year-roundoccupancy presents prob-lems for the utilities servingthem.

• Because manufacturedhomes are elevated, air infil-tration can become a seriousproblem over time as the so-called “belly board”4 andcrossover duct beneathbecome compromised bymoisture, animals, or mater-ial breakdown.


4 In most manufactured homes, a “belly board” holds the insulation in place under the floor and serves as a vapor barrier.

5 Data shown for manufactured homes are from NRECA’s 2011 Manufactured Housing Survey; data for all housing units are taken from: Energy Information Administration. 2005 Residential Energy Consumption Survey, Table HC2.4 –Space Heating Characteristics by Type of Housing Unit. Note that heating saturation data from the two sources citedare not directly comparable; hence, the comparison is a crude one.

6 Robert Scott, Director of Energy Services for the National Association of State Community Service Programs, comments that the age of the unit has a significant bearing on its energy efficiency and that manufactured homesshipped from the South to the North may have no insulation at all.

Manufactured Homeswith Electric Heating

Manufactured Homeswith Heat Pumps

All Housing UnitsHeating Primarily with

Electricity (2005)

Manufactured Homeswith Central A/C

Manufactured Homeswith Window A/C

0% 10% 20% 30% 40% 50% 60% 70%

FIGURE 2: Energy Sources for Heating and Cooling in ManufacturedHomes vs. All Housing Types5

Energy sources for heating also vary betweenmanufactured and site-built homes, as shown inFigure 2. Electric heating is more prevalent in

manufactured homes, accord-ing to NRECA’s ManufacturedHousing Survey. In compari-son, only about 30% of allhousing units nationwide in2005 used electricity as theirprimary heating fuel. One Al-abama electric co-op has esti-mated that as much as 30% ofits system peak is driven byelectric furnaces in manufac-tured homes. Data on air con-ditioning in manufacturedhomes show that summer

peak contributions also can be very significant,although the air conditioning saturation is roughlycomparable to that in other types of housing.The level of peak demand contribution in eitherseason is increased by the lower levels of insu-lation typically seen in manufactured homes, theuse of single-glazed windows, uninsulateddoors, and relatively higher levels of air leakageand infiltration, compared to site-built homes.6

For electric cooperatives, the message is clear:energy efficiency retrofit programs designed tomeet the needs of the site-built housing stockmay not be effective in manufactured housing.Failure to understand what is unique aboutmanufactured housing also can lead to missedopportunities to upgrade energy efficiency inthis important customer segment. Electric co-opsthat focus on the ways in which manufacturedhomes are uniquely different from site-builthomes will be able to deliver effective andhighly targeted energy efficiency programs.

Energy efficiency

retrofit programs

designed to meet the

needs of the site-built

housing stock may

not be effective in

manufactured housing.

THE IMPERATIVE FOR ENHANCED ENERGYEFFICIENCYElectric cooperatives serve a large number ofcustomers living in manufactured homes andthis magnifies the problem of energy-inefficientmanufactured housing units. NRECA’s Manu-factured Housing Survey targeted electric coop-eratives likely to serve a large number of theseunits. On average, electric co-ops responding tothe survey reported serving between 3,000 and5,000 of these units, or about 25% of their over-all residential customer population. Customers living in manufactured homes

account for far more than their representativeshare of high-bill complaints. A typical responsefrom a North Carolina electric co-op was that,while manufactured homes represent only abouta quarter of residential customers served, theyaccount for fully half of all high-bill complaints.In a more extreme case, one South Carolinaelectric co-op asserted that 98% of its high-billcomplaints come from members in manufac-tured homes. Another co-op reported that itshighest incidence of bad debt charge-offs occursin manufactured homes, observing that themonthly electric bill for these accounts often exceeds the member’s rent payment.


5 – Extremelyimportant

4

3

2

1 – Not at allimportant

0% 10% 20% 30% 40% 50%

39%

35%

20%

5%

1%

FIGURE 3: How Surveyed Electric Cooperatives Rated the Importance of Improving the Energy Efficiency of Manufactured Housing in TheirService Territories. (Source: NRECA 2011 Manufactured HousingSurvey)

Key findings of NRECA’s 2011 Manufactured Housing Survey include the following:

• Members living in manufactured housingunits are the most likely to have high electricbills (due to energy inefficiency) but are theleast likely to be able to pay such bills, lead-ing to late payments, arrears, and charge-offs.

• Owner/occupants are often financially unableand/or unwilling to invest the amount ofmoney needed to make the requisite upgradesto improve their homes’ energy efficiencysignificantly.

• Landlords who rent manufactured homesgenerally are unwilling to make the neededinvestments, as typically they are not respon-sible for the unit’s electricity bills. One elec-tric co-op reported that some landlordsforbid their tenants to allow a home energyauditor on the premises. A second co-opnoted that it had written off more than $2,700to five different tenants of a single landlord-owned property over a three-year period.

• About one-fifth of manufactured homesserved were built before 1976, when theHUD Code went into effect. These are likelyto be the least energy-efficient units whilealso among the most expensive to retrofit.

• Not only do manufactured housing unitsaccount for a disproportionate share of anelectric co-op’s loads, but cooperative staffspend a great deal of time dealing with high-bill complaints from occupants of these units.

As Figure 3 indicates, many electric co-opsconsider manufactured housing energy effi-ciency to be a very important issue. In addition,

. . .63% of electric

co-ops surveyed

expect the level of

importance of

energy efficiency

in manufactured

housing to increase.

63% of electric co-ops surveyed expect the levelof its importance to increase in the future.As noted above, manufactured homes also can

contribute disproportionately to a cooperative’soverall system peak demand, which often playsa large role in determining the utility’s wholesalepower costs. With a high percentage of electricfurnaces for heating and a high saturation of airconditioning, manufactured homes can drive autility’s weather-driven peak demand in eithersummer or winter. Such a situation is portrayedin the case study of Coosa Valley Electric Coop-erative described later in this report.

WHAT DO ELECTRIC CO-OPS NEED TO KNOW TO ADDRESS THE PROBLEM?What information must electric cooperatives haveon hand for each customer account/premise servedto determine if there is a problem and, if so,how to address it? Electric co-ops need to gatherand maintain the following basic information:

• Which of its members live in a manufac-tured home

• What type of manufactured home it is,e.g., single-wide, double-wide, etc.

• Year it was built, especially before orafter 1976

• What type of primary heating and cool-ing systems it has, e.g., electric furnaceor heat pump, central A/C or windowA/C units, or both

• Monthly kWh usage for the premisesover time

• Hourly kW demands of high kWh usageaccounts (if available through the electricco-op’s AMR/AMI system or other smartmetering)

A later section of this report, “ManagementChecklist: A Place to Begin,” covers how to usethese data.


As this report already has established, manufac-tured housing units differ from site-built homesin ways that make them both less energy effi-cient and harder to retrofit. This section delvesinto the unique challenges that cooperativesmust both understand and overcome to be ableto address the energy problems of manufac-tured homes.

COMMON PROBLEMS ASSOCIATED WITHSERVING MANUFACTURED HOMESElectric co-ops report a wide range of problemsstemming from providing electric service tomembers living in manufactured homes. In addi-tion to these households’ disproportionate shareof high-bill complaints, respondents to NRECA’sManufactured Housing Survey identified a num-ber of related problems, shown in Figure 4.These percentages reflect how often electriccooperatives report a problem; for example,64% of them report high-bill complaints.The problems shown fall into two categories:

those that occur because manufactured homesare energy inefficient and those that reflect

cooperatives’ frustrations with attempts to address the root causes of energy inefficiency.

ELECTRIC HEATING SYSTEM ISSUESElectricity is by far the most prevalent source for heating in manufactured homes, with electricresistance/electric furnaces and heat pumps together accounting for as much as 80% of allheating systems, according to the NRECA Manu-factured Housing survey. However, almost nonew manufactured homes ship with a heat pumpand, while a heat pump can be installed in anew manufactured home at an incremental costof only a few hundred dollars, dealers appearreluctant to offer this option. As a result, incen-tive programs offered by some electric co-ops to replace electric furnaces in existing manufac-tured homes with higher-efficiency heat pumpsare unable to achieve a net gain in the overallsaturation of heat pumps. Also, while ductlessheat pumps may be an attractive option forsome manufactured homes, the majority typi-cally contain too many small rooms for this technology to be most effective.7

Unique Challenges of Manufactured Housing

7 For more details, see CRN’s 2010 Technology Brief “Ductless Heat Pumps.”

FACTORS CONTRIBUTING TO ENERGYINEFFICIENCYElectric cooperatives are well versed in dealingwith energy problems in manufactured homes,albeit reactively and one high-bill complaint ata time. Many co-ops have invaluable hands-onknowledge of what creates these problems.Figure 5 lists the percentages that co-ops par-ticipating in NRECA’s Manufactured HousingSurvey reported as specific contributing factors.Factors cited by electric co-ops represent both

of the following:

• Direct causes of poor energy performance,e.g., leaky ductwork

• Obstacles to addressing the energyinefficiency problem, e.g., owners not infinancial position to make investments

These will be discussed in turn.

DIRECT CAUSES OF ENERGY LOSSESDesigning energy efficiency retrofit programsthat work in manufactured homes requires anunderstanding of how design, construction, and

operating factors contribute to energy losses, especially in older manufactured homes whereless efficient windows and doors exist andweather-stripping has deteriorated over time.Fortunately, these factors are easily identifiable.They are:

• Air leakage/infiltration—the need for airsealing is most often cited in manufacturedhomes, as significant losses are associatedwith leakage of warm or cold air from occu-pied spaces. Infiltration of excessive outsideair, requiring heating in winter and cooling/dehumidification in summer, also can be amajor problem. Specific causes of air leakagein manufactured homes include deterioratedweather stripping, gaps in the “marriage wall”that joins the multiple units making up thehome (see Figure 6), holes in the ends ofducts, gaps around wall registers and behindwashers and dryers, and unsealed backing tothe electrical panel.

• Crossover ducts—air leakage also is preva-lent in crossover ducts that run beneath thefloor of double- and triple-wides to connect


High-bill complaints (winter)

Energy conservation measuresdifficult to implement

Billing delinquencies/charge-offs/late payments

High-bill complaints (summer)

Recommendations from energyaudits not followed

Customer service reps spend inordinateamount of time with members

Existing energy efficiency programsnot easily applied to mfg housing

Customers report beinguncomfortable in home

No response

0% 20% 40% 60% 80%

FIGURE 4: Most Commonly Reported Problems in Serving Members in Manufactured Housing.(Source: NRECA Manufactured Housing Survey)

If difficult to implement: CountWhy?

Too expensive 54

Landlord unwillingness 47

Not many products suited 42for manufactured housing

Don’t follow audit 35recommendations

64%

61%

48%

48%

43%

31%

28%

22%

32%

the sections of the home. These ductsoften are made of flexible tubing andso are prone to collapse and easy foranimals to penetrate. Crossover ductsmade of thin sheet metal can leak.Ductwork connections made withduct tape simply deteriorate over time.In any of these cases, the resultingleaks will spill heated or cooled insideair underneath the home. Figure 7shows a compromised crossover ductprior to replacement of the electricfurnace with a heat pump and instal-lation of all new ductwork.

• Lack of insulation—insulation levelsand associated R-values in manufac-tured homes can be woefullyinadequate. There is insufficient wallthickness to achieve the R-valuesrequired in local building codes forsite-built housing; such wall thicknessgenerally relies on 2x6 wall studs.8

Floors and ceilings also may lack adequate insulation.

• Heating systems—most manufacturedhomes come with electric furnaces,not heat pumps, and this lowers theirenergy efficiency. In addition, heatpumps added later often are oversizedfor the heating load of the unit


Owners not in financial position tomake large investment upgrades

Leaky ductwork

Deterioration of insulation and other materials

Leaky building envelope

Poor construction

Owner’s unwillingness to make large investments in upgrades

Lack of occupant knowledge of operating heating/AC

Wrong type of heating system

Poorly sized heating system

No response

0% 20% 40% 60% 80%

61%

57%

52%

49%

46%

43%

37%

33%

21%

32%

FIGURE 5: Common Factors Contributing to Manufactured Housing EnergyEfficiency Problems. (Source: NRECA Manufactured Housing Survey)

FIGURE 6: Air Gap in “Marriage Wall.” (Photocourtesy of Tideland EMC)

FIGURE 7: Badly Compromised Crossover Duct. (Photo courtesyof Tideland EMC)

8 An R-value indicates an insulation's resistance to heat flow. The higher the R-value, the greater the insulating effectiveness. The use of larger-size wall studs in manufactured homes does not necessarily mean that higher levels of insulation are installed by the manufacturer, according to Manuela Heyn of Gulf Coast Electric Cooperative.

because dealers often do not know how todetermine proper sizing.

• Uninsulated ductwork—ductwork itself maynot be wrapped with insulation, allowingheating and cooling losses due to differentinside/outside temperatures.

• Lack of vapor barrier in the roof cavity andbelow the home—moisture penetration degrades the performance of insulation, sothe lack of a vapor barrier in the roof aboveand/or crawl space below some manufac-tured homes can lead to lower energy efficiency and mold problems.

• Belly board problems—in most manufac-tured homes, the belly board holds the insula-tion in place under the floor and serves as avapor barrier. Plumbing that runs under thefloor is on the warm side of the insulation toprotect it from freezing in winter. However,the belly board can be damaged by animals,deteriorate over time, or become torn, allow-ing the floor insulation to become moisture-laden or simply fall out, exposing ductworkand dramatically increasing energy losses.Often there also is long-term water damagefrom leaky pipes, toilets, and showers thathas compromised floor, insulation, and bellyboard integrity. These problems must be addressed prior to basic weatherization.

• Thermostat placement—in addition to thefact that few manufactured homes may haveprogrammable or set-back thermostats, place-ment of thermostats can be problematic. Theymay be placed too close to a heating source,such as a fireplace, causing the heating system to operate inefficiently. Some co-opseven report cases in which the heating andair conditioning in manufactured homes arerunning simultaneously.

• Single-glazed windows and uninsulateddoors—most manufactured homes come withsingle-glazed windows and uninsulated doors,which have a low associated R-value (mean-ing that the rate of heat transfer betweenconditioned interior spaces and the outdoors

is higher than ideal for conservation of heat-ing or cooling).

• Seasonal patterns of energy use—some co-opspoint to summer months as the epicenter ofthe high-bill problem in manufactured homes;in winter, many owners use propane as asupplemental heating source, thus loweringthe impact on electric bills. However, suchdual-fuel heating arrangements also can makethe home’s peak demand contribution in winter outsized when compared to its kWhenergy usage, as members turn to their electric furnace on the coldest days.

MANUFACTURED HOME EFFICIENCY RETROFIT CHECKLISTThe good news is that it is easy to addressmany of the known causes of energy losses in manufactured homes. Feedback from homeenergy auditors and weatherization assistancepersonnel indicate that the energy conserva-tion measures (ECMs) shown in Table 1 generally are worth considering in manufac-tured home retrofit programs in response tothe energy loss factors listed in the previoussection.9

BARRIERS TO IMPROVING ENERGY EFFICIENCYEven when the utility and the manufactured-home customer agree that energy efficiency canbe improved, a number of barriers often stand inthe way of a home receiving retrofit measures.

• Lack of staff resources at the electric co-op—a common theme emerging from discussionswith electric co-ops about manufactured-home energy efficiency is that lack of man-power is the utility’s biggest obstacle. In manycases, only one home energy auditor is avail-able to respond to all high-bill complaints and this individual typically has other respon-sibilities as well. Moreover, the number ofnew manufactured homes coming onto thetypical rural electric system outpaces the


9 ECMs that work equally well in manufactured and site-built homes, such as compact fluorescent lighting (CFL), refrigerator replacement, and water heater wraps, are not listed here specifically. For a more comprehensive list, see:U.S. Department of Housing and Urban Development. “Manufactured Homes: Saving Money by Saving Energy.”

co-op’s ability to retrofit existing homes, creating an uphill climb for the co-op.

• Occupants lack financial means or access tofinancing—while data indicate a wide varietyof household income levels in manufacturedhousing, low-income residency acts as a barrier to energy efficiency retrofits. Manyhouseholds simply cannot afford to do morethan no-cost/low-cost measures, even when ahome energy audit indicates a short payback

on higher-cost measures, such as appliancereplacements or HVAC system changes. These households’ poor credit ratings alsomay preclude access to low-cost financing.

• Landlord resistance—since landlords of manufactured homes generally do not pay theutility bills, they typically are reluctant to makeinvestments to improve energy efficiency. Inaddition, as mentioned earlier, some landlordsare hostile to the very presence of the utility’s


Low/Moderate Cost Cause of Energy Losses Retrofit Measures ($$$) Capital Improvement ($$$) Rate Incentives

Air Leakage • Install weatherstripping• Caulk leaky windows and doors• Install gaskets in electrical wall sockets• Seal duct connections and ends• Seal plenum below furnace• Install skirting around base of home to

prevent animal damage to belly board and floor insulation

Compromised • Seal crossover duct • Replace flexible crossover ducts Crossover Duct with metal

Lack of Insulation • Add insulation to attic space and below floor, if accessible

Inefficient or Improperly • Clean/replace furnace filter • Replace electric furnace with • Provide rebate for heat pump Operated Heating System • Clean/replace air filter heat pump replacement

Inefficient Cooling System • Clean/replace air filter• Clean condensing coils• Install window A/C covers

Uninsulated Ductwork • Install duct insulation wraps

Lack of Vapor Barrier • Install vapor barrier in ceiling andfloor, if accessible

Belly Board Problems • Repair or replace belly board

Thermostat Placement • Relocate thermostats away fromfireplaces and stoves

Single-Glazed Windows/ • Upgrade windows to double- Uninsulated Doors or tripled-glazed

• Upgrade doors to higherefficiency units

High Winter Peak Demand • Offer a peak demand controlContribution incentive to customers with

propane backup to their primaryelectric system

TABLE 1: Checklist of Retrofit Measures Likely to be Cost-Effective in Manufactured Homes

home energy auditor, evenwhen the tenant has com-plained about high electricbills.

• Master metering—in somecases, several manufacturedhomes may be totalized ona single electric meter, caus-ing the landlord to“allocate” the total billacross several tenants. Thepresence of an older, lessefficient unit in the clustermay impose unnecessarilyhigh costs on the otherunits. Such a situation willbe difficult for the utility to address withoutinstalling separate metering for each unit,and the landlord may oppose such a meter-ing change.

• Lack of time-of-use rates—while manufac-tured housing units have the potential tocontribute disproportionately to the utility’speak demand, few electric co-ops have time-of-use rates that would recover the costs ofthis impact from members living in these unitsand provide a financial incentive to reduceelectric demand.

• Customer skepticism about electricity savings—some electric co-ops point to

member skepticism about savings as a key barrier tospending to improve energyefficiency.

CONTRIBUTING FACTOR:POOR QUALITY OF WORK BYTHIRD PARTIESMost electric co-ops reportthat they do not hire contrac-tors directly to provide neededweatherization services, ductrepairs, and HVAC upgrades in manufactured homes. Manyrefer members to independentcontractors for service or refer

income-qualified members to their local weath-erization assistance agencies. In some cases,however, electric co-op personnel performingfollow-up inspections have found the quality of work performed by these third parties to bepoor. In cases of HVAC upgrades and system replacements, approved contractor lists do notalways ensure quality work, particularly whenlisted firms send out new or less qualified em-ployees to perform the work. Some contractorfirms apparently fail to understand the uniqueways in which energy can be lost from manufac-tured homes, which are different from those insite-built housing.


A common theme

emerging from

discussions with

electric co-ops about

manufactured-home

energy efficiency is

that lack of manpower

is the utility’s biggest

obstacle.

Electric cooperatives have awide variety of energy effi-ciency programs, some ofwhich can be applied readilyto manufactured homes. How-ever, 80% of electric co-opsthat responded to the relevantquestion in NRECA’s Manufac-tured Housing Survey indicatedthat they do not offer ECMsspecifically targeted at manu-factured housing. Given theunique characteristics of manu-factured homes highlighted inthis report, programs designedfor site-built homes may not be

effective in achieving desiredsavings levels in manufacturedhomes. Moreover, the processby which electric co-ops address energy problems ofmembers living in these unitsalso may need rethinking.Failure to offer programsspecifically effective for manu-factured homes or adopt amore proactive process islikely to perpetuate the mem-ber’s high monthly bill andthe utility’s excess wholesalepower costs.

Failure to offer

programs specifically

effective for

manufactured homes

or adopt a more

proactive process is

likely to perpetuate

negative impacts on

the member’s monthly

bill and the utility’s

wholesale power costs.

Creating an Energy Efficiency Retrofit Program that Works

RETROFIT PROGRAMS OFFERED BY ELECTRIC CO-OPSThose residential energy efficiency programsthat electric cooperatives offer and are consid-ered applicable to manufactured homes areshown in Figure 8. While these programs workin individual cases, they are generally not proac-tive or easily scaleable.

CURRENT PROCESS: TRIGGERED BY THE HIGH-BILL COMPLAINTMany of the electric co-ops contacted for this re-port tend to follow a similar process when re-sponding to a high-bill complaint from a memberliving in a manufactured home―a process dif-fering very little from that used in site-builthomes. The typical approach is as follows:

• Receive customer high-bill complaint.• Conduct walk-through, energy audit of manufactured home.

• Test electric meter.• Perform a load check, e.g., determine if heating system is running in summer.

• Install water heater blanket, CFL light bulbs,and other no-cost/low-cost ECMs.

• Provide customer with list of further recom-mended ECMs to reduce kWh usage.

• Refer income-eligible members to local weath-erization assistance agency for insulation, ductrepairs, weather stripping, and other low-costconservation measures.

• Offer financing for HVAC and/or applianceupgrades with loan repayment via the electricbill (this is not a widespread practice amongcooperatives, however).10


Home energy audit

Heat pump incentives

Energy-efficient heating systems

Appliance rebates

Energy-efficient lighting

Home weatherization

Energy-efficient A/C systems

Renewable energy systems

Special rate offers

No response

0% 10% 20% 30% 40% 50% 60%

55%49%

30%26%

26%23%

25%21%

23%20%

23%20%

15%15%

8%5%

7%6%

38%45%

FIGURE 8: Residential Energy Efficiency/Renewable Energy Programs Offered by Electric Co-ops.(Source: NRECA Manufactured Housing Survey)

10 Midwest Energy’s How$mart is one such utility financing program.

Offered by co-op

Applicable to manufactured homes

What are the key weaknesses of such a reac-tive process?

• By the time of the complaint, the manufac-tured home customer is already obviouslyunhappy with the cost of his or her servicefrom the electric co-op.

• The ad hoc nature of this process is disrup-tive to utility staff, who may be stretched toothin already, with the result that only a fewhomes can be handled at any one time.

• The process is unlikely to identify the manu-factured homes in which retrofits would


FIGURE 9: Proactive Model for Manufactured Housing Retrofits

CustomerInformation &Billing System

Install Weatherization Measures—Insulation/Duct Repairs/Air Sealing

Finance CapitalImprovements

Track Post-Installation kWh Usage/kw Demand

Conduct EducationalAwareness Campaign

Install Capital Improvements:HVAC/Thermostats/Doors & Windows

Identify Existing ManufacturedHousing Units Served

Collect and StoreUnit Characteristics

Track Monthly kWh Usageby Unit

Identify High-Usage Units forTargeted Follow-Up

Contact Target Customers

Identify Cost-EffectiveRetrofit Measures

Conduct ManufacturedHome Energy Audit

CustomerInformation &Billing System

MHEA Software

Screen

Target

Retrofit

Evaluate

Outreach

Adjust/Update List of Cost-Effective Retrofit Measures

produce the greatest financial benefit for the utility―in peak demand reduction, for example.

• Data on all manufactured homes served,which would be invaluable for program plan-ning, are not collected and stored routinely.

• Co-ops rarely pursue follow-ups to deter-mine what energy conservation measures actually were installed and how much energywas saved.

• Without access to financing, many customersin manufactured homes cannot afford toimplement ECMs recommended by their electric cooperative.

PROACTIVE RETROFIT MODEL FORMANUFACTURED HOMESElectric cooperatives have the ability to alter thestatus quo of reacting to high-bill complaintsfrom members living in manufactured homes.Figure 9 suggests a systematic approach throughwhich the energy challenges associated withidentifying and retrofitting energy-inefficientmanufactured housing units can be better managed proactively. Under such a proactive approach, manufac-

tured housing units on the system are identifiedand earmarked as such on the customer recordin the co-op’s customer information system. Thedata typically needed are listed in “What DoElectric Co-ops Need to Know to Address theProblem?” (page 5). Updating the customerdatabase can be done over a period of timethrough a variety of data collection avenues—by revising the Application for Service form, creating a summer internship project to patrolthe service territory and visually record manu-factured housing characteristics, or usingGoogle aerial imagery to locate manufacturedhome parks and count units, for example. In the absence of a pressing need, such as a sus-pected high peak demand contribution associ-ated with manufactured homes, the co-op may elect to take several years to complete this data-gathering task.Once housing characteristics and associated

kWh usage data are available, the cooperativecan systematically identify high kWh-usagemanufactured homes and approach members

with the offer of a free manu-factured-home energy audit.The co-op will be able to showthe member how his or herhome’s usage compares withthat of similar units—e.g., sin-gle- or double-wides—on theutility’s system. These will beapples-to-apples comparisons,since similar weather condi-tions will have influenced theenergy usage of all the homesbeing compared. In addition to conducting a

home energy audit specificallytailored to a manufacturedhome, the auditor also coulduse a software tool, such asMHEA (Manufactured Home Energy Audit).11 MHEA analyzes energy use andevaluates possible weatherization retrofit mea-sures in existing manufactured homes; electricco-ops can use MHEA to determine appropriatemeasures for these homes. Since many weather-ization assistance programs also use this tool,consistency will be improved between weather-ization improvement recommendations to re-duce air leakage and heat loss and others aimedat appliance and HVAC system upgrades. Noneof the electric cooperatives contacted during thisstudy reported using this software. Once cost-effective ECMs have been identified,

the electric co-op should perform needed weath-erization work along with capital improvements.In the case of low-income members in manufac-tured homes, the co-op should work closely withits local, county, or state weatherization assistanceprogram to ensure that retrofit actions are imple-mented. A good working relationship betweenthe co-op and the agency must exist to make

sure the customer’s needs aremet and high-quality workperformed. The cooperativeshould do a follow-up inspec-tion of all work and providefeedback to all parties, includ-ing third-party contractorshired by either the electric co-op or the weatherizationassistance agency. The electric cooperative

should consider offering fi-nancial incentives or low-costfinancing to owner-occupantsof manufactured homes forwhich it has recommendedcostly upgrades, such as con-version of electric furnaces tohigh-efficiency heat pumps

(see case study of Coosa Valley Electric’s Manu-factured Home Heat Pump Conversion Pro-gram). Loan payments can be made via thecustomer’s monthly bill payment, as lower kWhusage generates offsetting dollar savings for themember.Actual savings can be tracked by comparing

post-retrofit kWh usage against historical billingrecords.12 This information is very valuable forthe following reasons:

• Confirms that measures actually save what the home energy audit and MHEA indicated

• Identifies high-kWh usage; this informationhelps the co-op to determine which manu-factured homes also should be monitored for peak demand savings

• Can be incorporated into a ManufacturedHome Energy Savings Guide13 and an educational awareness campaign for members living in these housing types


11 The MHEA software was developed by the National Renewable Energy Laboratory (NREL) and is supported by Oak Ridge National Laboratory (ORNL). The software is part of The Weatherization Assistant, a package available atnominal cost. Instructions for obtaining The Weatherization Assistant can be found at: http://weatherization.ornl.gov/assistant_obtain.shtml.

12 For guidance on estimating energy savings associated with efficiency retrofits, see CRN’s 2010 Technology and Program Brief “Estimating Electricity Savings: Decision Making, Methods, and Practices in Measurement and Verification (M&V).”

13 A simple and effective Manufactured Home Energy Savings Guide has been created by Coosa Valley Electric.

Electric co-ops can

use MHEA to

determine appropriate

weatherization retrofit

measures for

manufactured homes.

None of the electric

cooperatives contacted

during this study

reported using this

software.

http://weatherization.ornl.gov/assistant_obtain.shtml


Coosa Valley Electric Cooperative (CVEC) provides a financial incentive for members living inmanufactured homes to convert to a heat pump.

Alabama-based CVEC had a fundamental problem that had to be addressed. Growth in the numberof manufactured homes, whose electric furnace heating systems were contributing as much as 30%of CVEC’s winter peak demand, was imposing large and increasing costs on the cooperative’s entire system. To make matters worse, CVEC’s wholesale power contract contains a demandratchet, which carries the higher seasonal peak (winter) through the following summer period for purposes of determining wholesale costs.Nine years ago, CVEC implemented

a heat pump conversion program toaddress this peak demand problem.Through this program, the co-op workswith its consumers and local HVACcontractors to retrofit existing manufac-tured housing units with heat pumps.The average retrofit cost is about$2,000, so CVEC works with the home-owner to arrange financing, which typically is covered by the energy savings on the household’s monthlyelectric bills. The co-op subsidizes the conversion with a rebate of up to $600; this is shared by CVEC andPower-South Energy Cooperative, itspower supplier. In addition, CVEC replaces flexible crossover ducts with metal ducting suspended from the frame of the home to prevent moisture build-up and discourage animal intrusion. Also, thermostats mounted near thefireplace or in an area with poor air flow are relocated, often to a hallway, to better balance temperatures throughout the home and reduce system consumption.CVEC has tracked monthly energy savings of selected program participants. The co-op noted

January and February savings averaging around 50% for both kilowatt-hours and billed costs. Withmonthly bill savings of $150 in January and February, the payback period on the customer’s netcost of conversion (after a $600 rebate) is expected to be as short as three to four years. CVEC reports that response to its program has been good and that the program has become its primarysolution for most high-bill complaints. The co-op also works with manufactured home dealers toimprove the energy performance of new units.

Key Ideas

• 31% of CVEC’s members live in manufactured or mobile homes, with several thousand new manufactured homes added across Alabama annually.

• CVEC has determined that the largest contributorto its winter peak demand is electric furnaces inmanufactured homes.

• Total connected load of electric strips can rangefrom 15kW to 37kW per home, translating intomegawatts of contribution to system peak.

• Rebates of up to $600 are offered to homeownersfor conversion of electric furnaces to heat pumpsand other measures to improve energy efficiency.

The Case of Coosa Valley Electric

There are a number of ways that managementcan sharpen its focus on the manufactured hous-ing problem and, if necessary, create a moreproactive process to deal with it. The followingmanagement checklist offers a sensible startingpoint for action.

•�Gather member andpremises data on manufac-tured homes served (basicdata elements identified earlier in this report).

•�Determine if there is a problem to be addressed:n Number of high-bill complaints and staff time to respond;

n Arrears and charge-offs;n Excessive peak demandcontributions.

•�Offer a small-scale pilot program to members livingin manufactured homes,including a home energyaudit, MHEA analysis, retrofit recommendations, a possible rebate for heatpump conversion, andoptional rate incentives for peak demand control of heating and/or A/C.

•�Monitor monthly kWh usage as a follow-up to installation of recommended measures.

•� Install check metering or use AMI to confirmlevel of demand reduction by program participants.

•�Determine whether an expanded-scale program is warranted and identify associated resource requirements.

•� Conduct an educational awareness campaignand, if an expanded program is to be offered,a recruitment drive.

The following additional strategies also maybe useful for management consideration:

INCORPORATING ENERGY EFFICIENCY INTO THESERVICE INITIATION PROCESSCooperatives can modify the Application for Service to gather important pieces of infor-mation about new manufactured homes being

connected. The co-op canprovide those applying formembership with a Manu-factured Home Energy Guideand conduct a walk-throughto point out potential sourcesof energy losses. In this way,the co-op can warn owners ofmanufactured homes if theyare likely to receive high electric bills and present themwith a list of cost-effectiveECMs for consideration. In extreme cases, the co-opmight institute a condition ofservice requiring those whoapply for cooperative mem-bership to sign a disclaimerstating that they have been in-formed about their unit’s grossenergy inefficiency and waysthey can address the problem.

PROVIDING INCENTIVES FOR PURCHASE OF AN ENERGY STAR-RATEDMANUFACTURED HOME To stem the tide against more low-efficiencymanufactured homes being added to the hous-ing mix, some electric cooperatives offer rebatesfor the purchase of an ENERGY STAR-ratedmanufactured home. For example, electric co-ops that are members of the Northwest EnergyEfficient Manufactured (NEEM) Housing Pro-gram provide a rebate to purchasers of NEEM-and ENERGY STAR-labeled manufactured homesand a cash incentive to sales representativeswho sell electrically heated NEEM homes lo-cated within their service territories.14 Thesehomes are estimated to save 30% on heating


ManagementChecklist: A Placeto Begin

In extreme cases, the

co-op might institute

a condition of service

requiring those who

apply for cooperative

membership to sign

a disclaimer stating

that they have

been informed about

their unit’s gross

energy inefficiency

and ways they can

address the problem.

14 One participating electric co-op is Flathead Electric in Montana. For further information on its program, see www.flatheadelectric.com/energy/neem/neem.html.

www.flatheadelectric.com/energy/neem/neem.html

bills compared to manufactured homes built tocurrent federal standards.15

FINANCING EFFICIENCY RETROFITS USING THE MONTHLY BILLWhile not common among electric co-ops, fi-nancing of energy efficiency retrofits such asheating system conversions can be offeredthrough the co-op, with loan payments col-lected through the monthly electric bill. Energysavings enable the customer to afford the loanpayments. Where this has been done, the loangenerally is tied to the premises, not the mem-ber, to avoid losses when ownership of the unit changes.

CUSTOMER AWARENESS CAMPAIGNSFinally, many electric co-ops contacted duringthis study commented that lack of customerawareness of energy efficiency exacerbates theproblem of an inefficient manufactured home—customers fail to consider energy efficiencywhen they purchase the home, some do not op-erate the units properly, many overlook simplemeasures that could reduce energy consumption,and many do not have enough faith in the esti-mates of energy savings to make the needed up-grades to their homes. Cooperatives that educatetheir members about these issues will encounterless resistance to their programs and can havegreater confidence that recommended ECMs ultimately will be implemented.


15 Oregon Department of Energy, Northwest Energy Efficient Manufactured (NEEM) Housing Program, www.oregon.gov/ENERGY/CONS/RES/manhme.shtml.

Conclusions

Additional Information

Manufactured homes are a chronic source offrustration for both members and many electriccooperatives’ staff. These homes can be grosslyenergy inefficient, contribute disproportionatelyto system peak demands, produce an excessivenumber of high-bill complaints, and present bar-riers to the cooperative’s ability to do what isright for the customer. This problem is eminentlyfixable, however, as experiences by leading

electric cooperatives demonstrate. Careful man-agement consideration of how to deal with thechallenges of manufactured homes in a proac-tive manner will focus attention on the rootcauses and change the dynamics in ways thatraise the odds of success. Experience shows thatthe most effective approaches are those that en-able the homeowner to address the problem ina well-informed, effective, and affordable way.

Conner, C.C., R.G. Lucas, H.E. Dillon, and M.Lubliner. Pacific Northwest National Laboratory.“Revision of the Energy-Efficiency Requirementsin the Manufactured Home Construction andSafety Standards.” June 2004. Available atwww.pnl.gov/main/publications/external/technical_reports/PNNL-14458.pdf.

Foremost Insurance Group. “ManufacturedHomes Market Facts Report 2008.” Available atwww.foremost.com/products/mobile-home/market-facts.asp.

Lucas, Robert. Pacific Northwest National Labo-ratory. “DOE Energy Efficiency Standards forManufactured Housing (presentation).” April 28,2010. Available at www.nfpa.org/assets/files/PDF/CodesStandards/MHCCHUD/MHCCDOEBriefingEnergyEfficiencyStandards_MH-RobertLucasPresentation.pdf.

Manufactured Housing Institute. HUD Manufac-tured Housing Construction and Safety Standards.Available at www.manufacturedhousing.org/lib/showtemp_detail01.asp?id=1905&cat=Advocacy.

www.pnl.gov/main/publications/external/technical_reports/PNNL-14458.pdf

www.foremost.com/products/mobile-home/market-facts.asp

www.nfpa.org/assets/files/PDF/CodesStandards/MHCCHUD/MHCCDOEBriefingEnergyEfficiencyStandards_MH-RobertLucasPresentation.pdf

www.manufacturedhousing.org/lib/showtemp_detail01.asp?id=1905&cat=Advocacy

Missouri Department of Natural Resources En-ergy Center. “The Energy-Efficient ManufacturedHome: A Guide for Missourians.” Available atwww.dnr.mo.gov/pubs/pub1208.pdf.

National Renewable Energy Laboratory. Manu-factured Home Energy Audit software (MHEA).Available at http://weatherization.ornl.gov/assistant_obtain.shtml.

National Rural Electric Cooperative Association,Market Research Services. 2011 ManufacturedHousing Study Survey Results. February 2011.

Oregon Department of Energy. Northwest En-ergy Efficient Manufactured Housing Program.Available at www.oregon.gov/ENERGY/CONS/RES/manhme.shtml. See also: www.energy.idaho.gov/informationresources/d/mhlighting125.pdf.

Shultz, Kelly. Federation of American Scientists.“Evaluating Residential Energy Efficiency Programs with a Universal Metric.” Available atwww.fas.org/programs/energy/btech/policy/Evaluation%20energy%20efficiency%20programs.pdf.

South Carolina Energy Office. “Energy Savingsfor Manufactured Homes.” Available at www.energy.sc.gov/publications/Energy_Savings_for_Manufactured_Homes.pdf.

South Carolina Energy Office. “$aving Money in Your Manufactured Home Through Energy Efficiency.” Available at www.energy.sc.gov/publications/$aving%20Money%20in%20Your%20Manufactured%20Home.pdf.

U.S. Department of Energy. “ManufacturedHome Energy-Efficient Retrofit Measures.” Available at www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10230.

U.S. Department of Housing and Urban Development, Office of Policy Development and Research. “Manufactured Homes: SavingMoney by Saving Energy.” August 2005. Available at www.huduser.org/portal/publications/destech/saveEnrgy.html.

U.S. Environmental Protection Agency and U.S.Department of Energy. “Getting Started with ENERGY STAR Qualified Manufactured Homes.”Available at www.energystar.gov/index.cfm?c=bldrs_lenders_raters.pt_builder_manufactured.


http://weatherization.ornl.gov/assistant_obtain.shtml

www.oregon.gov/ENERGY/CONS/RES/manhme.shtml

www.oregon.gov/ENERGY/CONS/RES/manhme.shtml

www.energy.idaho.gov/informationresources/d/mhlighting125.pdf

www.energy.idaho.gov/informationresources/d/mhlighting125.pdf

www.fas.org/programs/energy/btech/policy/Evaluation%20energy%20efficiency%20programs.pdf

www.energy.sc.gov/publications/Energy_Savings_for_Manufactured_Homes.pdf

www.energy.sc.gov/publications/$aving%20Money%20in%20Your%20Manufactured%20Home.pdf

www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10230

www.huduser.org/portal/publications/destech/saveEnrgy.html

www.energystar.gov/index.cfm?c=bldrs_lenders_raters.pt_builder_manufactured

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