On the Path to Zero Energy Homes

Lew W. PratschBuilding America Program

U. S. Dept. of Energy

Association for EnergyService Professionals

Zero Energy Home BrownBag

August 24, 2006

Buildings39%

Industry33%

Transportation28%

Buildings use 71%of electricity

21%

18%18%

Why Buildings: Huge Opportunities

Residential

Heating32%

Other 4%

WaterHeat13%

Computers 1%

Cooling10%

Refrigeration 9%

Lights12%

Electronics 5%

Wash 5% Cooking 5%

Source: 2004 Buildings Energy Databookwith SEDS distributed to all end-uses

Commercial

Other10%

Lights 28%

Heating16%Cooling

13%Water Heat 7%

Ventilation 7%

Cooking 2%Computers 3%

Office Equip 7%

Refrigeration 4%

Moving Toward Zero Energy Homes

• Today’s marketable ZEH—cut utility bills atleast 50% including EE & renewable energy

• Tomorrow’s ZEH—Energy savings of 50-70% plus 30-50% on-site renewable energy

• Integrate/optimize best components forwhole house design by climate zone

Progression to Full ZEH by 2020NAHB-RC national survey (February 2006) shows 82% consumer acceptance of

ZEH when energy savings offset mortgage increase

Building America ApproachExperts in building science and system engineering

offer home builders cost-shared technical support– Design assistance– Energy modeling– Performance specification writing– Training and workshops– On-site consulting– Monitoring– Access to Building America research

• Develop Building America’s Best Practice series

Systems Engineering Research ConsidersMoisture and Thermal Climate Zones

Zero Energy Home Benefits• Zero (Net) Energy• Zero Peak Load• Zero Emissions• Zero Complaints (from homebuyers)• Zero Cost (83% in Nat. Survey of 1700

indicated that positive cash-flow withmortgage & utility bills is fine)

• Ideally suited for Time-of-Use pricing• Improved comfort of homebuyers

Zero Energy Homes CoverageNo More Electric Bills

Well, not quite. But 'zero-energy homes' keep them low.“…power bills routinely topped $200. The grand total over the 10 months they’ve

lived in the three-bedroom stucco and stone house: $75.” August 15, 2005

2006 ACEEE SummerStudy—”Less is More:En Route to ZeroEnergy Buildings”

ZEH Builders/Suppliers

SheaHomes• First major production home builder in Nation to

build ZEHs as standard in a subdivision– 306 homes sold out one year early– Shea Homes appreciated faster– More profitable to offer as standard than as option– If builder, utility or major manufacturer provides

warranty, buyer accepts• SheaHome Features

– Homes about 40% better than Title 24– All have solar water heaters– 120 have 1.2 kw or 2.4 kw of PV (about 25 upgraded)

• SheaHome shifted subdivision under constructionfrom above code to ZEH in four months

SheaHomes, San Angelo, San Diego

SheaHomes & Comparison Surveys

• 367 surveys delivered• 231 (63%) response rate ($10 included in

survey)• 132 (57%) of respondents signed utility

release forms• Qualitative analysis at 2002 ACEEE• Preliminary survey findings reported at 2004

ACEEE Summer Study

Property Value Appreciation

$9,301$14,492Mean $ gain/mo.owned

44.7%55.4%Mean % of $ gain

$262,968$306,510Mean $ gain

28.1 mos.22.5 mos.Mean length of owner-ship before resale

17 – 40.2 mos.9.9 – 43.9 mos.Length of ownership(range)

ComparisonSheaHomesVariable

Bill Savings vs. Comparison Homes(Actual Gas & Electric Utility Bills)

54%$ 80Shea SEE + 2.4 kW PV

29%$123Shea SEE + 1.2 kW PV

14%$149Shea energy efficiency &solar water heating (SEE)

NA$174Comparison homes

%Savings

Avg.Monthly BillHome Category

Respondents Agreeing with Statements

81%91%80%Federal Gov. should supportZEH R&D

84%91%80%CEC should give a rebate forsolar PV & solar water heaters

92%93%92%Builders should build very EEhomes if they cost less/monthto own/operate

Con-trol

Shea PVowners

SheaNon- PV

SunChoice™ Power Meter

PV Owners Digital Display Feedback

• Shows PV kWh production & householdconsumption in real time or cumulatively

• 58% used the digital display at least once aweek (15% once a day)

• 70% help change energy-consuming behavior• 40% help determine if system was functioning• Homeowners who selected 2.4 kw PV nearly

doubled energy saving vs 1.2 kw PV system

PV Owners Like Utilities

• PV owners have more positive attitudestoward SDG&E than do non-PV owners

• Believe electric rates have come down• 67% of PV owners brag about utility bills vs.

26% of non-PV owners• Appears that cutting utility bills over 50% is

a tremendous attention getter for selling newhomes and provides bragging rights

Clarum Homes

• Building only ZEH in the future• Over 500 ZEHs completed including

townhomes & apartments• Selling faster than competition• ZEH Senior Community under construction• Hundreds of ZEHs planned in 6 subdivisions

Premier Homes ZEH Community

Premier & Morrison Homes

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Typical New Home ComfortWise / EnergyStar

Premier BA & ZEH

Annual Energy Bill Comparison

Other Energy UseWater Heating

Space CoolingSpace Heating

Average Monthly Elect. Bills

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PremierNon-ZEH

Today® News Show Testimonials• “Our utility bills were $150-200/m with the 4

of us in a smaller house. Here it’s a biggerhouse & the bills are $30-50/m”

• “I’m pretty upset when he calls & says--Mymonthly bill was $6. What’s yours lookinglike—I’m forking out about $265”. TodayShow, May 26, 2006, See link below:

• http://video.msn.com/v/us/v.htm?g=fead2a8e-5d44-41bc-85dd-1528fae31594&f=rssimbot_us_m_3549&fg=email

Centex Homes• Second Generation ZEH

– Power Save Plus saves over 50% of traditionalenergy, including solar electric

– Zero electric bill based on time-of-use rates– Positive cash flow - annual energy savings

exceed incremental increase in mortgagepayments

– Power Save options offered at Design Center– 56% take $4,000 energy efficiency upgrade

• 2006—Building 30 home ZEH subdivision

ZEH Market Research (CA)• If you have a product that is both energy

efficient AND green, over 2/3 of themarket is going to be interested in it.The appeal of a two-pronged attack ismuch wider. (Source: America LIVES,Inc)

John Wesley Miller• NAHB’s 2005 Energy

Value Housing AwardBuilder of the Year

• 99 ZEH• Heating/cooling bills

guaranteed at about$1/day by Tucson Elect.

• PV & SWH• Average utility bill is

$15.73/m including $5meter fee

ZEH Developments in California

64%1.8 kw70Pajaro VistaClarum Homes

56%2.4 kw99SacramentoPremier Homes

57%2.4 kw50SacramentoPremier Homes

47%Varied257WatsonvilleClarum Homes

62-66%2.4149SacramentoGrupe Homes

>50%TBD1600Hunter’s PtLennar Homes

58%3.5 kW32San RamonCentex Homes

62%2.4 kw16San DiegoSheaHomesSavingsPV# ZEHLocationBuilder

NAHB-Research Center ZEH Study• ZEH has the potential to reverse National upward

trends in home energy consumption• Evaluated homeowner attitudes & opinions

– Focus Group– National internet survey of 1,700 homeowners

• Market research findings– Over 80% will buy ZEH with positive cash flow between

mortgage and utility bills– Buyers want credible guarantees from builder, major

manufacturer or utilities for new features

How do we achieve full ZEH?• Continue to aggressively address EE & Solar R&D• Address biggest remaining loads such as water &

space heating loads, and plug loads• Design for Zero Peak Communities• Automate energy management system

– Plug Load Study– Smart Economizer, TOU, Gridwise, etc

• Create demand (Prior to 2005-- Builders sayHomeowners are not asking for energy efficiency)

Zero Peak Communities

• Zero summer peak load when utility needs it• How will utilities value ZEH?

– Capacity, distribution, transmission benefits– Ideal for Time-of-use rates– Real time pricing– Net-metering

• California’s ZENH (1kw summer peak load)• Green product, RPS or competitive contract

SMUD’s Analysis of 36 Homes• 18 ZEH Premier Homes compared to 18 control

homes shaved peak by 55% on 107 degree day• And, control homes were designed to shave

peak about 35%• Sample included 5 Premier Homes with east

facing PV system—if all PV was on south towest facing the July peak reduction would havebeen 67% or .86 kW

Utilities—Dampen Capacity, & T&DGrowth

• Closing in on “zero-peak-demand” communitiesAvg Peak Demand ZEH vs Non-ZEH July 15, 2005

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Average of ZEH Net Grid Load (kW)

Average of Power Produced by PV (kW)

Average of Non-ZEH Net Grid Load (kW)

Avg Peak Demand SavingsNoon -7 pm

1.95 kW

High Temp 107 degrees FMin Temp 71 degees F

Avg Peak Demand Savings @ 5 pm 1.51 kW

Peak Load Reduction Potential in High Growth Market:Phoenix, Arizona

200,0002100k existing homesw/CPP & automatedenergy management

10,00052,000 Zero PeakCondos

128,7006.619,500 Zero PeakHomes (30% of new

Home starts)

Technique kW Reduction Total kW

TotalSavings:340 MWSystemLoad:6020 MW

3 ZEH Business Models• Optional ZEH—hardest to sell

– Sales staff must be trained & motivated• Pre-plotted 10-30% as ZEH—sells fine

– Excellent PR– ZEH sells as fast as other homes

• Full ZEH subdivision– Excellent PR– Builders say, “Sell faster than nearby subdivisions”– Homebuyers do not seek ZEH but like it once they have

it, plus they brag about it– Given two “equal” subdivisions the ZEH subdivision

sells better than the conventional subdivision

Zero Energy Home Summary• Today’s ZEH, i.e. cutting utility bills at least

50% sells very well• Zero Peak Communities improve grid• Dozens of National events—Extreme

Makeover, CNN, Today Show, NAHB ShowHome, CBS Evening News, & Newsweek

• ZEH has the potential to reverse National upwardtrends in home energy consumption

For Additional Information• Buildingamerica.gov• Lew W. Pratsch @ 202 586-1512• lew.pratsch@ee.doe.gov