Hood River Passive House David Hales Washington State University Extension Energy Program, BA-PIRC

March 2013

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Hood River Passive House

Prepared for:

The National Renewable Energy Laboratory

On behalf of the U.S. Department of Energy’s Building America Program

Office of Energy Efficiency and Renewable Energy

15013 Denver West Parkway

Golden, CO 80401

NREL Contract No. DE-AC36-08GO28308

Prepared by:

David Hales

BA-PIRC/Washington State University Extension Energy Program

22 N Havana ST. Suite 204

Spokane, WA 99202

NREL Technical Monitor: Stacey Rothgeb

Prepared under Subcontract No. KNDJ-0-40339-00

March 2013

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Contents List of Figures ............................................................................................................................................. v List of Tables ............................................................................................................................................... v Definitions ................................................................................................................................................... vi Executive Summary .................................................................................................................................. vii 1 Project Description ............................................................................................................................... 1

1.1 Introduction ..........................................................................................................................1 1.2 Background ..........................................................................................................................1 1.3 Climate .................................................................................................................................2

2 Building Characteristics ...................................................................................................................... 3 3 Modeling ................................................................................................................................................ 4 4 Analysis ................................................................................................................................................. 6 5 Conclusions .......................................................................................................................................... 9 6 Ongoing Research .............................................................................................................................. 10

6.1 Long-Term Testing ............................................................................................................10 6.2 Long-Term Testing Analysis .............................................................................................10

7 Logistics .............................................................................................................................................. 11 7.1 Location of the Project .......................................................................................................11 7.2 Contact Information ...........................................................................................................11 7.3 Detailed Timeline...............................................................................................................11

8 References .......................................................................................................................................... 12

List of Figures Figure 1. Hood River passive house architectural rendering............................................................... vii Figure 2. Hood River passive house near completion ............................................................................ 1 Figure 3. Hood River passive house site energy from BEoptE+ ............................................................ 5 Figure 4. Hood River passive house source energy from BEoptE+ ...................................................... 5 Figure 5. Hood River passive house electrical use by measure ............................................................ 7

Unless otherwise noted, all figures were created by WSU-EEP.

List of Tables Table 1. Passive House Performance Requirements .............................................................................. 1 Table 2. Climate Data .................................................................................................................................. 2 Table 3. Hood River Passive House Project Characteristics.................................................................. 3 Table 4. BEoptE+ VS PHPP Source Energy (MBtu/yr)............................................................................. 4 Table 5. Cost Analysis of Individual Measures ........................................................................................ 8 Table 6. Contact Information.................................................................................................................... 11 Table 7. Timeline Summary ...................................................................................................................... 11

Unless otherwise noted, all tables were created by WSU-EEP.

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Definitions

ACH50 Air changes per hour at 50 pascals

BA Building America

BA-PIRC Building America Partnership for Improved Residential Construction

BEoptE+ Building Energy Optimization

CFL Compact fluorescent lamp

DHW Domestic hot water

DOE Department of Energy

EF Energy factor

EPS Expanded polystyrene

ft2 Square foot

HRV Heat recovery ventilator

HSPF Heating seasonal performance factor

IECC International Energy Conservation Code

kBtu Thousand British thermal units

kWh Kilowatt-hour

LED Light-emitting diode

MBtu Million British thermal units

PHPP Passive House Planning Package

SEER Seasonal energy efficiency ratio

SIP Structurally insulated panel

WSU-EEP Washington State University Extension Energy Program

yr Year

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Executive Summary

The Washington State University Extension Energy Program, a Building America Partnership for Improved Residential Construction team member, has been working with builders in the marine and cold climates of the Pacific Northwest to develop exceptionally efficient residential construction practices for more than 20 years. The Hood River Passive House Project (see Figure 1) was developed by Root Design Build of Hood River, Oregon, using the Passive House Planning Package to meet all of the requirements for certification under the European Passive House standards. The passive house design approach has been gaining momentum among residential designers for custom homes. Building Energy Optimization modeling indicates that these designs can actually exceed the goal of the U.S. Department of Energy Building America Program to “reduce home energy use by 30%–50% (compared to 2009 energy codes for new homes). The project was initiated in 2009 but market conditions delayed final completion until the third quarter of 2012. The project did not involve Building America Partnership for Improved Residential Construction input into the design process but was instead initiated to evaluate the output of the passive house design process as supported by the Passive House Institute US in North America.

This report documents the short-term test results (blower door testing and on-site confirmation of as-built characteristics) of the Shift House and compares the results of Passive House Planning Package and Building Energy Optimization modeling of the project. The design includes high R-value assemblies, extremely tight construction, high performance doors and windows, solar thermal domestic hot water, heat recovery ventilation, movable external shutters, and a high performance ductless mini-split heat pump.

Cost analysis indicates that many of the measures implemented in this project did not meet the Building America standard for cost neutrality. The ductless mini-split heat pump, the lighting fixtures, and the advanced air leakage control system were the most cost-effective measures. The future challenge will be to value engineer the performance levels indicated here in modeling using production-based practices at a significantly lower cost.

Future efforts include long-term monitoring to verify the actual performance of whole-house energy use and interior conditions affecting comfort.

Figure 1. Hood River passive house architectural rendering

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1 Project Description

1.1 Introduction The Hood River Passive House Project was developed by Root Design Build of Hood River, Oregon, using the Passive House Planning Package (PHPP) to meet all of the requirements for certification under the European Passive House standards. The passive house design approach has been gaining momentum among residential designers for custom homes. Building Energy Optimization (BEoptE+) modeling indicates that these designs can actually exceed the goal of the U.S. Department of Energy Building America Program to “reduce home energy use by 30%–50% (compared to 2009 energy codes for new homes)”. Table 1 summarizes the passive house performance standards. The project did not involve Building America Partnership for Improved Residential Construction (BA-PIRC) input into the design process but was instead initiated to evaluate the output of the passive house design process as supported by Passive House Institute US in North America (see Passive House Institute US [2007] for more information).

Table 1. Passive House Performance Requirements

Space Heat Demand <4.75 kBtu/ft2-yr Space Cooling Demand <4.75 kBtu/ft2-yr

Total Source Energy <38.0 kBtu/ft2-yr Mean Ambient Radiant Interior

Surface Temperatures >68°F

Frequency of Overheating (>77°F) 10% of time Ventilation Heat Recovery Ventilator (HRV)

1.2 Background The Passive House Institute US conducted training in 2009 in Portland, Oregon, and Seattle, Washington. Approximately 60 architects, contractors, and mechanical engineers attended the training sessions. The training stimulated a number of projects in the region including the Shift House in Hood River. As the project developed BA-PIRC facilitated the acquisition of materials to enhance the project, including windows and doors from Internorm in Austria. Because of financing and other market conditions the project moved slowly but completion is anticipated by the third quarter of 2012.

Figure 2. Hood River passive house near completion

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Research in Europe conducted by the Cost Efficient Passive Houses as European Standards project and monitoring of early passive house projects in the United States for Building America (Stecher and Allison 2012) have shown that modeled predictions compare well with the measured performance of completed passive houses. Production builders have been reluctant, however, to embrace measures required to meet passive house standards because of assumed costs and the often nontraditional approaches used for space conditioning. The BA-PIRC team did not furnish design assistance on this project. The Washington State University Extension Energy Program (WSU-EEP), a BA-PIRC team member, approached this project as an opportunity to evaluate the passive house design approach and process outcomes, document home performance, track costs, and determine obstacles to moving the passive house into a cost-effective production environment.

1.3 Climate The Hood River Passive House is located near the east entrance to the Columbia River Gorge in climate zone 5 dry. Table 2 gives climate data.

Table 2. Climate Data

Heating Degree Days65 5,499 Cooling Degree Days70 88 Annual Precipitation 30.0 in.

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2 Building Characteristics

The Shift House in the Hood River Passive House Project is a 2,004-ft2 (1,674 ft2 as defined in PHPP analysis) two-story house built on a slab on grade (see Table 3).

Table 3. Hood River Passive House Project Characteristics

Measure 2009 IECC Climate Zone 5 Hood River Passive House Walls R-value 20 50.5a

Slab-on-Grade R-Value 10 43.5a Ceiling R-value 49 76.6a

Heat Pump HSPF/SEER 7.7/13.0 11/22 DHW Electrical EF 0.87 Solar thermal

Ventilation ASHRAE 62.2b HRV Windows U-Value 0.32 0.09 a

Doors U-Value 0.32 0.13 a Air Sealing 7.0 ACH50 0.3 ACH50 tested

Shading Not required Movable exterior Lighting 40% CFL 100% CFL + LED

a Values as derived in PHPP b ASHRAE (2010). Notes: IECC, 2009 International Energy Conservation Code (International Code Council 2009); HSPF, heating seasonal performance factor; SEER, seasonal energy efficiency ratio; DHW, domestic hot water; EF, energy factor; CFL, compact fluorescent lamp; LED, light-emitting diode The high R-value walls were achieved with 8-in. structurally insulated panels (SIPs) covered with an additional 4 in. of expanded polystyrene (EPS) sheathing. The vaulted ceilings are 12-in. SIPs also covered with an additional 4 in. of EPS sheathing. The slab on grade has full slab and perimeter 9-in. EPS. All the fenestration is from Internorm in Austria with U-values as prequalified by Passivhaus Institut. These values, however, do not necessarily equal published values derived from standardized test methods. DHW is generated by a solar thermal system with electric resistance backup. HVAC is supplied by a single-head, high performance, ductless mini-split heat pump with electric resistance baseboards as backup and an HRV set up to meet ASHRAE 62.2 (2010). Shading to protect against overheating is provided by a system of automatic movable exterior panels.

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3 Modeling

Modeling was done using BEoptE+ 1.2 and the 2007 U.S. version of PHPP (see Table 4).

Table 4. BEoptE+ VS PHPP Source Energy (MBtu/yr)

Energy Use Building America Benchmark from

BEoptE+

BEoptE+ Hood River House

PHPP Hood River House

Heating 46.2 1.0 5.0 Cooling 8.4 7.3 4.8 DHW 40.9 6.4 2.8

Large Appliances 26.0 12.1 8.6 Lighting 19.6 12.7 2.4

Ventilation Fan 1.6 2.8 4.2 HVAC Fan 8.3 0.9 0.7

Miscellaneous 39.2 38.8 8.6 Total 190.2 82.0 37.1

BEoptE+ modeling predicts a 57% reduction in whole-house source energy reduction. PHPP indicates an 80% source energy reduction from the Building America benchmark as modeled in BEoptE+ (see Figures 3 and 4). The large discrepancy is mostly associated with assumptions about modeling miscellaneous loads but significant variations are also seen in lighting, DHW, and cooling. Some of the cooling difference might be a result of the inability of BEoptE+ to directly model the exterior movable shading included in the project. For BEoptE+ modeling, interior shading was assumed with no wintertime shading and 80% summertime shading.

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Figure 3. Hood River passive house site energy from BEoptE+

Figure 4. Hood River passive house source energy from BEoptE+

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4 Analysis

Comparisons between passive house design development using PHPP and modeling with BEoptE+ and other simulation programs suggest some fairly large discrepancies. Refer to Table 3 for a comparison of the BEoptE+ modeling of the Shift House and the PHPP results. Similar results have been reported before (Building Industry Research Alliance 2010).

Differences in definitions might cause some confusion. PHPP uses different conventions for determining conditioned floor area and house volume. PHPP measures floor area from the interior surface of exterior walls; only counts a percentage of storage, utility and stair floor area; and subtracts the volume of interior walls and floor cavities from the house volume. The net effect is that the PHPP values for energy use per square foot and ACH must all be reduced for comparison to BEoptE+ and other simulations. Table 3 attempts to make these adjustments by normalizing the area and volume values to those used in BEoptE+.

BEoptE+ modeling and design optimization would have resulted in a different structure with overall lower performance driven primarily by construction cost considerations. Although BEoptE+ modeling suggests that the home is overglazed, this might be a result of the inability of BEoptE+ to model the exterior automatic shading. This is seen in the relatively high cooling energy predicted by BEoptE+ (Table 3). The passive house process using PHPP is driven by design performance, not construction costs.

Figure 5 shows the on-site electrical energy savings associated with individual measures based on BEoptE+ modeling. For the modeling, each measure was treated individually as if it were the only measure applied to the base case design (ICC 2009). This approach does not show possible interactive effects between measures that influence the total package performance (i.e., a better enclosure reduces the savings from improved HVAC efficiencies but could reduce equipment costs by allowing downsized systems). The approach does help see the relative importance of different measures. As an example, additional air sealing has a much larger impact than adding insulation to the roof, as seen in Figure 5.

Using the modeled savings shown in Figure 5 and measure cost data supplied by the builder, and comparing builder-supplied cost data to baseline measure costs from the BEoptE+ cost library, incremental measure costs were calculated (see Table 5). Assuming 10 ¢/kWh for electricity and a 3% discount rate over 30 years for a typical mortgage, the present values of the electrical savings were calculated for each measure. Comparing the 30-year present value of savings for each measure to the measure’s incremental cost allows the affordability of the measure to be gauged.

Only the lighting and the ductless heat pump show cost neutrality or better within the expected measure life. Advanced air leakage control has a 30-year present value close to its measure cost, but the overall package is far from cost neutrality.

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Figure 5. Hood River passive house electrical use by measure

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Table 5. Cost Analysis of Individual Measures

Measure 2009 IECC (ICC 2009)

Baseline Measure

Cost

Hood River Passive House

Passive House

Measure Cost

Savings kWh/yra

Present Value of Electrical

Savingsb

Incremental Measure Cost as

Reported

Walls R-Value 20 $3.52/ft2 42.3 $9.41/ft2 959 $1,879.68 $18,000

Slab-on-grade R-Value 10 $2,218 63.7 $7,480 422 $827.14 $5,262

Ceiling R-Value 49 $2.55/ft2 70.2 $10.68/ft2 229 $448.85 $10,975 Heat Pump HSPF/SEER 7.7/13.0 $2,285 11/22 $3,750 2,285 $4,478.70 $1,4654c

Water Heating EF = 0.87 $258 Solar thermal $9,748 2,076 $4,069.05 $9,490

Ventilation ASHRAE 62.2 (2010) $463

Energy Recovery Ventilator

$1,850 –188 ($368.49) $1,387

Windows U-Value 0.32 $24.30/ft2 0.09 $35.60/ft2 1,206 $2,363.81 $6,650 Air Sealing 7.0 ACH50 $0.00/ft2 0.4 ACH50 $2.40/ft2 2,370 $4,645.30 $4,800 Lightingd 40% $0.05/ft2 100% $0.08/ft2 491 $962.38 $60

Shading Not required

Movable exterior

744 $1,458.27 $5,000

All Measures

9,425 $18,473.42 $63,089c a Savings modeled as first measure in in all cases bAssumes $0.10 kWh and 3% discount rate over 30 years c Additional savings might be anticipated in the package analysis for equipment downsizing and if central forced air ducts are assumed in the base case and eliminated from the project house. d Percentage of lighting fixtures using CFLs or LEDs.

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5 Conclusions

Both modeling and monitoring (Stecher and Allison 2012) indicate that the passive house design approach can produce the level of performance needed in the building enclosure to meet Building America goals for new construction homes. As a design process, the passive house process produces an extremely high performance design rooted in proven building science applicable to climate zones in the Pacific Northwest. The process as seen here does not ensure meeting the cost–benefit goals of Building America but instead appears to be driven by noneconomic market forces. The challenge is to adapt measures to the production building environment while finding significant cost reductions and optimizing measure cost versus the cost of renewable energy generation.

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6 Ongoing Research

6.1 Long-Term Testing As soon as the Shift House is completed and occupied, the home will be instrumented for long-term monitoring. A flow meter was preinstalled in the solar thermal DHW system. Individual electrical loads for heating, DHW backup, the HRV, cooking, and laundry will all be monitored at the panel and logged using an Onset HOBO U30 with Ethernet connectivity. Temperatures and humidity will be monitored room by room, at the energy recovery ventilator and the exterior. Radon and formaldehyde levels will be tested in the short and long term.

6.2 Long-Term Testing Analysis Data collected during long-term testing will be used to assess actual versus modeled energy use with the primary focus on envelope and HVAC equipment performance.

Room by room temperature data will be used to assess comfort relative to even distribution using a point source heating system in a high performance two-story envelope.

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7 Logistics

7.1 Location of the Project The Hood River Passive House is located at 4070 Belmont Dr., Hood River, OR 97031.

7.2 Contact Information Table 6 gives the project’s contact information.

Table 6. Contact Information

Team Contact Company Phone Email V.J. Jovanovic Root Design Build 503-515-6478 vj@rootdesignbuild.com

David Hales WSU-EEP 509-477-6702 halesd@energy.wsu.edu

7.3 Detailed Timeline Table 7 summarizes the anticipated timeline for the project.

Table 7. Timeline Summary

Instrumentation for Long-Term Monitoring First Quarter 2013(complete)

Complete Data Collection Fourth Quarter 2013 Long-Term Testing, Final Report (Draft) Third Quarter 2013

Long-Term Testing, Final Report Fourth Quarter 2013

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8 References

ASHRAE (2010). Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings. ANSI/ASHRAE Standard 62.2-2010. Atlanta, GA: ASHRAE. Accessed November 27, 2012: http://www.ashrae.org/standards-research--technology/standards--guidelines (available for purchase).

Building Industry Research Alliance (September 2010). Building America Gate 2 Artisans Group: 50% Marine Prototype (Interim Report). Stockton, CA: Building Industry Research Alliance. International Code Council (2009). 2009 International Energy Conservation Code. Country Club Hills, IL: International Code Council. Passive House Institute US (2007). Passive House Planning Package 2007. Urbana, IL: Passive House Institute US.

Strecher, D.; Allison, K. (2012). “Maximum Residential Energy Efficiency: Performance Results from Long-Term Monitoring of a Passive House.” ASHRAE Transactions (118:1).

DOE/GO-102013-3812 ▪ March 2013

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