Driving Innovation in Housing Technology

Building Towards Net Zero

Amber Wood

Manager, Energy Programs

NAHB Leading Suppliers Council

June 7, 2012

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NAHB Research CenterUpper Marlboro, MD

Housing R&D and laboratory testing Promote innovation Enhancing quality & affordability Promoting high standards for the

building industry

Building America

Private/public R&D partnership sponsored by DOE

Energy-efficient solutions for new and existing housing Technologies/Systems Whole-House Test Homes Quality Processes

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5Why ZEH?

What is ZEH?

Efficient Envelope

Renewable energy

systems

Efficient Equipment

Annually producing as much energy as consumed

Types of ZEH

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Builder-Installed Electric nZEH Production Accounts for All Builder-Installed End-Uses

All Electric nZEHProduction Accounts for All Electric

Total House nZEHProduction Accounts for All Electric + Excess to Account for Other Fuels

Net Producing HouseProduce > Consume

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ZEH Disclaimer

A Zero Energy Home is NOT:

Zero energy consumption Utility independent Energy rationed Energy unlimited

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The Basics

1. Decrease total energy use

2. Produce energy from renewable sources

Hathaway home, Purcellville, VA. NREL photo archive

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An Energy Efficient HomeHouse Shell:Added insulation, low-e windows, insulated foundation, overhangs, orientation

Heating & Cooling Equipment:High Efficiency, programmable thermostat, sealed ducts, ventilation

Water Heating: Solar preheat, efficient delivery, low-flow fixtures

Appliances: ENERGY STAR® Label

Lighting:Fluorescent fixtures/ bulbs, daylighting

Plug Loads & Appliances:Homeowner’s choice to decrease use

Air-sealing:Seal vents, holes and gaps through walls and roof

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Effect of Efficiency Upgrades

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Heating Cooling Water Heating Ventilation Air All Other Loads

Primary Energy Category

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Base House Net-Zero Design Reduction in Use

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Example ZEH Energy UseBaltimore, MD

PV System 5,700 W 500 sqft area Produce 8,266 kWh

Energy End Use

Base House Annual

Consumption (kWh)

Percent of

Total (%)

Net-Zero Annual Consumption

(kWh)

Percent of Total (%)

Heating 12,749 47 2,110 26

Cooling 5,100 19 850 11

Water Heating 3,627 13 167 2

Ventilation Air 0 0 175 2

All Other Loads 5,730 21 4,833 59

Annual Consumption 27,206 100 8,135 100

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ZEH Approaches

ZEH

Details Involving Builder, Trades, Government, etc.

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Current ZEH Experience

Over 50% minimum reduction in total energy Typically 50 – 70%

Net-zero electric bill Gas offset unavailable

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Solar Water Heating System

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Solar Electric (PV) Systems

Convert sun energy to electricity Operate daily Output varies

PV Systems are Available, Reliable, & Low maintenance Quiet

ZEH remodel in NJ, courtesy of Bill Asdal

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Utility Connection

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ZEH Utility Requirements

Utility must “net-meter”: credit for electricity fed back to the utility

Utility must “settle” credit not less than once a year

Utility must be ON to have PV power

Armory Park del SolA Historic Solar Community

John Wesley Miller Companies&

NAHB Research Center

Armory Park del Sol

Urban in-fill Southern Pacific RR executive

homes Existing infrastructure

Downtown Tucson Rio Nuevo Project Walking distance to downtown &

university Cultural activities, arts, & music

Armory Park del Sol

14 acre subdivision Purchased land in 1999 99 lots Construction started 2000

Historic Armory Park/ Armory Park del Sol Designs blend with area Neighborhood embraced

project Increased local property

values

Armory Park del Sol

Single family homes New technology/

construction methods Southwestern design Concrete construction

Thermal mass Metal framing

Termite-proof Significant energy

savings

Armory Park del Sol

Energy efficiency construction Thermal mass Exterior insulation Insulation through slab edge Raised heel truss, R-38 ceiling Dual-pane, Low-E & Low SHGC

windows Ducts in conditioned space 14 SEER heat pump HVAC system design with Manual J Optimized (reduced) duct runs Return air pathway from each room Passive ventilation system

Armory Park del Sol

Solar Electric Technology 1.5 kW Photovoltaic (PV) system minimum Garage roof mount (parapet wall) Utility approved components & systems;

annual utility inspection

Armory Park del Sol

Solar System Attributes One solar subcontractor (The Solar Store) Subsystems & components from major manufacturers

BP PV Modules Trace Inverters

Meets TEP SunShare requirements (ACC approved) Compliance

IEEE National Electric Code TEP Service Requirements Book

Armory Park del Sol

Single family homes Information age design

Minimum 3 telecom ports Digital Satellite Service CAT5e wiring Pre-wired for fiber optics

Security system Central vacuum

Armory Park del Sol

Utility collaboration Tucson Electric Power 5 year A/C guarantee

TEP inspects each home during construction Guarantee qualifies Armory Park del Sol for reduced

residential utility rates Guarantees heating & cooling portion of annual bill

Armory Park del Sol

Utility Collaboration / Solar Electric System State & federal tax credits Homeowner qualifies for TEP cash rebates Output offsets highest Time-of-Use rate TEP inspects solar electric system annually City permit fee credit up to $1,000

Armory Park del Sol

Solar Energy Homes in Downtown Tucson

An Award Winning Community!

SAHBA Builder of the Year, 2003

City of Tucson Most Energy Efficient Builder, 2003

Sonoran Institute Livable Community Award, 2005

NAHB Builder of the Year Award Winner, 2005

Metropolitan Pima Alliance Common Ground Award, 2006

Armory Park del Sol

APdS Standard Homes Predicted to use less than half the energy of a

typical regional home

Armory Park del Sol

John Wesley Miller Companies’ Net Zero Energy Home Project

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Zero Energy Home Construction

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Zero Energy Home at APdS

Natural extension of work at APdS

Engineering work funded by DOE through NREL

Goal of net-zero annual energy use

Started with clean sheet of paper

Zero Energy Home Design Team

NAHB Research Center, Inc.Project Management

Design SupportMonitoring

Project SummaryInformation Dissemination

Armory Park Del SolBuild

Define ConstraintsConsumer Education

Solar StoreDesign

Manufacturer ContactSolar Components

ManufacturersDesign Support

Product SpecificationInstallation Requirements

ConsumerInformationFeedback

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Zero Energy HomeConstruction Features

Concrete walls with 2” polyiso R-41 attic U-0.32, SHGC-0.35 windows SEER 18 AC Combined solar (128 sf) space and water

heating system with tankless backup 4.2 kW PV array PEX piping (with some copper) Fluorescent lighting throughout Outdoor living spaces Ceiling fans without light kits Energy Star appliances

Masonry Walls

2” Polystyrene

Radiant Roof Decking

Window & Porch Overhangs

Air Admittance Valves

Systems in Conditioned Space

4 kW PV System

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Tucson ZEH at Armory Park del SolMonthly Total Energy Use and Cost

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Ele

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kW

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-$20

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Energy Cost Utility Supply PV Supply PV Insolation

Values less than zero indicate sell-back to the utility

Modifications to solar thermal system complete

Now averaging about $10/mo (including $5.28 monthly base fee)

Average 23 kWh/day Total Average Energy Use

John Wesley Miller Companies’ Zero Energy Home (ZEH)

Blower, kWh, 663

A/C Compressor, kWh, 1,847

Demand Water Heater, kWh, 1,040

Other, kWh, 3,536

Refrigerator, kWh, 631

Lights, kWh, 651

Data from 9/1/05 to 8/31/06

Utility Supply,

kWh, 1158, 14%

PV Supply,

kWh, 7209, 86%

Tucson ZEHZEH End Uses

ZEH 1st Year Monitoring

ZEH Occupied Period Monitoring

ZEH Monitoring Results

Year 1 ZEH Monitoring Results

ZEH Monitoring ResultsInverter-Demand Heater

Compatibility

ZEH Monitoring ResultsPV System Output

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Plug Loads

The big challenge…

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Energy Simulation Summary

Description

Annual Electrical Consumption

Cooling Heating Fan DHW Lighting Appl/Othr Total

(kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr)

JWM Standard * 3,568 621 772 1,855 1,873 3,687 12,376

ZEH As-Built ** 2,207 200 430 158 779 3,072 6,846

Tucson Standard*** 6,770 669 1,229 4,064 1,873 3,687 18,292

*(includes passive SDHW)**(Option A+B+C+D+E w/ R41 ceiling instead of R43)***Light Frame, R19 ceiling, 10 SEER, double pane wood frame windows

Occupied Use To Date :

Demand Heater = 1,918 kWh, Lighting = 640 kWh, Other = 3,116 kWh

Total Use to Date = 6,406 kWh (26.3 kWh/day)

Estimated Daily = 18.8 kWh

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ZEH Lessons Learned

Project Success, Builder interest PV system

Utility interest prime Knowledgeable installer Inverter compatibility problems (new)

Solar Aesthetics Even with flat roofs

Solar thermal system performance Temperature limitations Controller Losses

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ZEH Lessons Learned

Integration of HVAC & thermal system Simple design/connections

Space and access for thermal storage Thermal mass

Winter penalties? Air admittance valves

Manufacturer design required Plumber reticence Work

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ZEH Lessons Learned

PEX plumbing Design is important Different installation

method Lighting

Whole-house permanent fluorescent lighting options NOT mainstream

New technologies emerging (LED, etc)

Plug loads still need control

ZEH2 Utility Savings Estimate PV system cost benefit offsets utility-supplied energy

John Wesley Miller Companies’ Zero Energy Home 2 (ZEH2)

ZEH2 Energy Features Tucson, AZ

Concrete Block Construction

Foundation 12” floating slab

Exterior Insulation 2” exterior insulation (R-13) Attached using z-strips

Ceiling & Roof Insulation R-38 ceiling insulation 1” rigid foam on roof deck

(R-6.5)

ZEH2 Energy Features(cont.)

High Efficiency Space Heating and Cooling Heat Pump: Trane XL19i Two-stage compressor Variable speed blower Sealed ducts in conditioned

space (22 CFM25 – total) Mechanical Ventilation

Mechanical room exhaust fan Fresh air to central return

Solar Hot Water Preheat System Closed loop 80G storage 64sf collector

Tankless Backup Water Heater

Manifold Distribution System

ZEH2 Energy Features (cont.)

ZEH2 Energy Features (cont.)

Efficient Windows U-value: 0.35, SHGC: 0.30

Air Sealing Package 740 CFM50

Lighting 90% Hard-wired fluorescent lighting ENERGY STAR fixtures CFL

Appliances ENERGY STAR Refrigerator,

Dishwasher, Washing Machine

Solar Electric PV System 6.93 kW (DC) PV

System Net Metered > 100%

Predicted Energy Savings with PV

ZEH2 Energy Features(cont.)

Code Approval & Programs

Meets all safety, health, and 2006 IBC & 2006 IECC code requirements

Tucson Electric Power’s (TEP’s) Guarantee program 5 year heating/cooling & comfort

Tucson Sustainable Energy Standard Performs 50% better than the Model

Energy Code Builders Challenge Builder Federal Tax Credit Local & State Tax Incentives

Quality Control RequirementsHigh Performance Home Specifications

Envelope Moisture Control

Foundation drainage/capillary breaks – n/a slab design

Climate appropriate vapor retarder – n/a due to climate & masonry wall construction

Continuous drainage plane – felt paper over fixed polyisocyanurate

Envelope Air Tightness

740 CFM50

Space Conditioning

Equipment and duct sizing per ACCA methodology

Space Conditioning (cont.)

Distributed whole house mechanical ventilation – exhaust fan and a central fan integrated supply

Local exhaust – bathrooms, kitchen

Filtration – Honeywell electronic air cleaner

Sealed ducts in conditioned space

No combustion appliances or fireplace

System capable of maintaining RH < 60%

Hot Water

SRCC rated collectors for solar hot water system

Quality Control Requirements High Performance Home Specifications

Neutral Cost Target

Upgrade Costs

Neutral Cost Target Efficiency Feature Upgrades

Note: PV not included

Neutral Cost Target Tax Credits & Incentives

Neutral Cost Target Efficiency Feature Upgrades w/ PV

Note: PV incentives not included for Std Home

Neutral Cost Target Efficiency Feature Upgrades w/ PV

Note: PV incentives included for Std Home

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Value of ZEH

ZEH2 Conclusions

APdS demonstrates increasing levels of energy efficiency

ZEH is possible Technologies “off-the-shelf,”

Attention to builder’s marketing effort is necessary Builders Challenge

Green Building

Local Utility Programs

ZEH1 MonitoringWhole House Energy Comparison – ZEH

ZEH2 MonitoringWhole House Energy Comparison – ZEH2

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Incentives

Federal Incentives

Tax Credit: 30% of cost with no upper limit

Expires: December 31, 2016

Details: Existing homes & new construction Principal residences & second homes Rentals do not qualify

79NEXUS EnergyHomes

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Incentive Details

Solar Water Heat Certified by SRCC or equivalent a Must provide ≥ 50% dwelling’s water heating Not apply to swimming pools/hot tub

Photovoltaics Wind Fuel Cells

$500 per 0.5 kW maximum Geothermal Heat Pumps

Meet federal Energy Star criteria

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Solar Renewable Energy Certificates (SRECs)

In SREC states, Renewable Portfolio Standard (RPS) requires some electricity from solar

The SREC program provides a means for SRECs to be created for every megawatt-hour of solar electricity created. 1 SREC = 1,000 kWh of solar electricity = 1

MWh of solar electricity 10 kW solar capacity = ~12 SRECs per year

Maryland SREC Market

Energy Year Jan 1 - Dec 31

SREC Useful Life 3 years

Solar Requirement Reaching 2% of total elec generated in 2021

Solar Alternative Compliance Payment (SACP) $400 through 2014

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Summary

ZEH used to be all about cost Still an interest in ZEH, driven by

Increasing utility costs Lower cost of PV Familiarity (owners & trades)

Consumer acceptance Utility acceptance New financing mechanisms

Changing accessibility

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Programs Energy Efficiency Certification

ENERGY STAR DOE Challenge Home

Energy Efficiency Research & Development Building America Program

Green Certification National Green Building Certification Program

Awards

References

NAHB Research Center Technical Website www.toolbase.org

DOE Energy Information Administration (EIA) www.eia.gov

DOE/EERE Buildings Energy Data Book http://buildingsdatabook.eren.doe.gov/default.aspx

ENERGY STAR www.energystar.gov

Database of State Incentives for Renewables & Efficiency (DSIRE) www.dsireusa.org

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Questions?

Driving Innovation in Housing Technology

Thank You!

Amber Wood

NAHB Research Center

Manager, Energy Programs

400 Prince George’s Blvd Upper Marlboro, MD 20774(direct) 301.430.6309 (fax) 301.430.6180

www.nahbrc.com