La Valentina North Affordable Townhomes

Transcription

1 La Valentina North Affordable Townhomes Near zero energy building report SMUD s Home of the Future Demonstration Program Prepared by Mike Keesee, Project Manager Energy Research and Development Sacramento Municipal Utility District September, 2012 Revised by TRC Energy Services to include post construction performance monitoring November, 2014

2 About the Zero Net Energy Buildings program SMUD s Zero Net Energy Buildings (ZNE) program is focused on demonstrating advanced building construction strategies and techniques to the local building community, home buying public, and building owners that incorporate high efficiency and on-site renewable energy technologies that result in the construction of zero net energy and zero peak buildings. Research is conducted through pilot projects with the goal of incorporating advanced building construction strategies and techniques into SMUD s new construction and solar programs. 2

3 Executive summary In 2009, SMUD partnered with owner/developer Domus Development LLC on the La Valentina North, an 18-unit affordable townhouse, Home of the Future (HOF) project. La Valentina was a research and demonstration project that combined advanced construction techniques with high efficiency building features and equipment and a virtual net metered solar photovoltaic (PV) system. Project goals included: 1. Operate as closely as possible to a zero net use of energy, including cutting annual source energy use by 80% and achieving zero net peak demand during SMUD s 4 to 7 p.m. summertime peak period. 2. Incorporate advanced framing techniques and HVAC design. The La Valentina North project consists of 18 3-bedroom affordable units in four, threestory row house apartment buildings (approximately 21,349 square feet) located at 12th and D streets, including: Building 1 (on 12th Street) o Three Unit A 3-bedroom flats on ground floor o Six Unit B 3-bedroom split-level townhouses on 2nd and 3rd floors o Three Unit C 3-bedroom split-level townhouses on 2nd and 3rd floors o 10 spaces of tuck-under parking on ground floor Buildings 2, 3 and 4 (on east end of parcel) 6 Unit D three-bedroom units, 12 parking spaces As part of La Valentina s design, project team members met with Domus and its design team to review design strategies and to develop a list of efficiency features to be included to achieve La Valentina s energy performance goals. The National Renewable Energy Laboratory (NREL) provided critical technical assistance in developing the project s energy efficiency measures. The project team conducted energy analysis using EnergyPro software, which models energy use for Title 24-regulated loads. The analysis showed La Valentina units on average would use 54.4% less TDV energy than a project built to the California 2008 Title- 24 Standards, including 63% less electricity and 48% less natural gas (see Table 1 and Table 2 below). Table 1: La Valentina estimated Title-24 standard design vs. proposed design Standard Budget (Meeting 2008 Title 24 Requirement) Proposed Budget La Valentina Energy Savings Area sf kbtu/sf-yr Per SF kbtu/yr Btu/sf-yr Per SF kbtu/yr % 19,875 1,420, , % 1,420, / = kbtu/sf-yr 648, / = kbtu/sf-yr 3

4 Table 2: La Valentina estimated Title-24 standard design vs. proposed design Unit Standard Proposed Margin kwh Therms kwh Therms kwh Therms Total 15,916 6,284 5,806 3,289 10,075 2,999 Average Savings 63% 48% The list of energy efficiency upgrades included is shown in Table 3 and includes high efficiency equipment, advanced envelope construction and high efficiency appliances. Table 3: Project upgrades Efficiency features Envelope: Roof /Attic 2008 Title 24 Baseline La Valentina North R-38 blown in fiberglass insulation in the attic with radiant barrier Walls (exterior) R-19 fiberglass batt in 2x6, 16 o.c. walls 4 R-42 blown in cellulose R-15 spray cellulose with 1 exterior EPS rigid and 1 foil face polyisocyanurate rigid insulation (R10) in 2x6,16 o.c. walls R-19 Fiberglass batts in floor joists Floor over garage R-19 Fiberglass batts in floor joists Infiltration testing 3.5 SLA 2.0 SLA NA 4 50 pa Glazing: Vinyl, dual pane Vinyl, dual pane U-Factor SHGC HVAC Heating system Gas furnace 0.80 AFUE Sealed combustion gas furnace 0.97 AFUE Cooling system 13 SEER/ 11 EER 19 SEER/ 13 EER Mechanical ventilation Duct insulation / location Bathroom exhaust R-6 insulated ducts in unconditioned attic w/6% 25 pa ENERGY STAR exhaust R-6 insulated ducts in conditioned attic w/ 3.75 % 25 pa Water heating 0.58 Energy factor storage tank less gas 0.82 Energy factor tank less gas gas unit Lighting Incandescent ENERGY STAR CFL and LED light fixtures PV system None 34.1 kw AC system (38.7 kw DC) 1.9 kw AC per unit Appliances Dishwasher Standard ENERGY STAR Cooking range Gas Gas Refrigerator Standard ENERGY STAR

5 Efficiency features HERS inspection/ testing 2008 Title 24 Baseline La Valentina North Duct leakage; building envelope sealing; cooling coil airflow & fan watt draw test; high EER equipment; refrigerant charge verification; maximum total cooling capacity; supply duct compliance credits; quality insulation installation HERSII rating 100* Typical Unit A 29 Typical Unit B 15 Typical Unit C 21 Typical Unit D 21 * A home with a HERS Index of 100 uses the same energy as a new home that meets California s 2008 Building Energy Efficiency Standards. A home with a HERS Index of 0 is a super-efficient Zero Net Energy Home that consumes no more energy than it produces with solar or other onsite renewable sources. The building also includes a 34.1 kw AC solar photovoltaic (PV) system that is estimated to generated 62,875 kwh per year, which is virtual net metered or equally divided among the La Valentina tenants (3,308 kwh per townhome). Many important lessons came out of this project based on the design and construction phases: The La Valentina project demonstrates the challenge of achieving zero net energy in multi-family housing but shows that zero peak is achievable. To achieve the Home of the Future 80% annual source energy savings goal would have required an additional 24 kw AC of photovoltaic, or 1.7 times the size of the installed PV system. To achieve an annual zero net energy (a building that produces as much energy as it uses) would require a PV system sized at 92 kw AC or almost three times bigger than the installed system. Installing exterior rigid foam insulation in multi-family buildings is challenging. Continuous exterior rigid foam can significantly reduce building heat gain and loss but the La Valentina design team, general contractor and subcontractors were hesitant to use continuous insulation. In particular, La Valentina employed a three coat stucco cladding and all parties were concerned that the continuous exterior rigid foam specification would not be able to support the three coat stucco cladding. As a result, an alternative attachment system using metal z-clips was used to attach the rigid foam that reduced the performance of the wall insulation system by approximately 6 to 10%. Rigid foam manufacturers need to develop attachment details for continuous exterior foam applications and educate the multi-family building industry on these details. The project team conducted a separate energy analysis using the BEopt software to predict a whole-house energy use including all end uses above and beyond those included in Title 24 analysis. Results of the BEopt analysis are presented in Figure 1 through Figure 20 and show that the units are predicted to save on average 60% energy. After the project construction was completed and the units occupied, SMUD engaged TRC Energy Services to monitor post-occupancy energy use at the unit-level and compare it to predicted energy performance. TRC monitored six dwelling units representing at least one 5

6 each of the four types of dwelling units at the property. Electric end-uses were monitored via a remote, web-enabled system called emonitor. Thermostats that communicate wirelessly with the emonitor system were installed in each monitored unit. Monitored data was collected for approximately 16 months, from summer 2012 to fall Results of the monitoring show electrical energy use for the six units monitored by TRC is higher by about 10% than predicted by the BEopt simulations. Monitored data indicates that the La Valentina units will have lower peak demand than what was predicted by the BEopt analysis. Per the BEopt analysis, La Valentina s estimated peak demand is 71% less than its Title-24 compliant peak demand. Monitored data collected over an August 8-13, 2012 heat storm from 3 occupied units shows that peak demand savings exceed the BEopt analysis with 77%, 75%, and 114% average 4 to 7 p.m. peak demand reduction compared to monitored SMUD multi-family gas heated customers 4 to 7 p.m. peak demand. 6

7 La Valentina Home of the Future fact sheet 12 th and D Streets Sacramento, CA Project parameters Structure: Four, three-story townhome buildings with 18 three bedroom, two bath units Total project cost: $4,702,500 hard costs, MEP design and related change orders Efficiency project cost: $551,662 total: Solar PV system ($238,500) and energy efficiency measures ($313,162). PG&E gas rebates: $5,863 SMUD solar incentives: $95,625 SMUD Solar Smart Home program incentives: $19,800* SMUD R&D incentives: $225,100* Completion date: May 2012 Estimated annual utility bill savings: 53% percent, approximately $521/year Estimated annual energy savings per unit: 63% annual source energy savings, including: 4,553 kwh/ year (73% reduction) and 178 therms per year (37% reduction) Solar Photovoltaic (PV) energy production: 3,308 kwh per year per apartment unit; 62,875 kwh/year total Title-24 compliance margin: 54.4% better than 2008 Title-24 Standards Project team Owner/Developer: Domus Development, LLC, Meea Kang, President; Gary Ahuna, Project Manager Architect: YHLA, Robert Lindley General Contractor: Brown Construction, Matt Curlette, Construction Superintendent, Dave Garner, Project Manager, Ryan Groomes, Project Engineer Project Management: Mike Keesee, Sacramento Municipal Utility District (SMUD) Energy Analysis: National Renewable Energy Laboratory (NREL), Davis Energy Group, Red Tape Express HERS Rater: Red Tape Express *SMUD SolarSmart and R&D incentives covered incremental costs of energy efficiency upgrades over California Title-24 energy efficiency requirements. 7

8 Introduction SMUD s residential new construction program, SolarSmart Homes, has encouraged builders to build new buildings that exceed the California Title-24 Standards. Under the SolarSmart Homes program, owners and builders of new homes receive construction incentives for projects that exceed California Title-24 standards by a minimum 20%. Under SB1, the California Solar Initiative, SMUD developed an incentive program to encourage the installation of solar electric photovoltaic systems on new and existing commercial buildings. In September 2008, the California Public Utilities Commission (CPUC) adopted the California Long Term Energy Efficiency Strategic Plan which adopted the follow goal: New Construction will reach zero net energy (ZNE) performance (including clean, onsite distributed generation) for all new single and multi-family homes by To meet the goal of zero energy homes by 2020, SMUD s Energy Research and Development (ER&D) unit embarked on a Home of the Future (HOF) project. ER&D define a Zero Energy Home as a home that produces as much energy as it uses. The Home of the Future would represent the next generation of new home construction and had two design goals to move residential new construction to Zero Energy: Reduce total home electric and gas usage (and utility bills) by 80 percent Be a zero peak home, that is, have zero electrical demand during SMUD s summer peak period, 4 to 7p.m. July and August. To achieve these goals, the HOF would feature commercially available new home construction techniques and technologies that should be commonplace in the next 5 to 10 years. The design process and energy efficiency measure selection Significant effort and time were devoted in the early design phase of the project in developing the construction strategies and technologies to be used in building La Valentina North. Several meetings were held with Domus project and design teams to review design strategies and agree on project goals before work began in earnest. Project goals include: Operate as closely as possible to a zero net user of energy, including cutting annual source energy use by 80% and achieving zero net peak demand during SMUD s 4 to 7 p.m. summer time peak period Incorporate advanced framing techniques and efficient HVAC design. The team developed a list of efficiency features for La Valentina designed to meet these energy performance goals and significantly exceed the project s California Title-24 requirements (see Table 4 below). 1 California Long Term Energy Efficiency Strategic Plan, California Public Utilities Commission, September,

9 Table 4: La Valentina Title 24 vs. Home of the Future specifications Efficiency features Envelope: Roof /Attic 2008 Title 24 Baseline La Valentina North R-38 blown in fiberglass insulation in the attic with radiant barrier Walls (exterior) R-19 fiberglass batt in 2x6, 16 o.c. walls R-42 blown in cellulose R-15 spray cellulose with 1 exterior EPS rigid and 1 foil face polyisocyanurate rigid insulation (R10) in 2x6,16 o.c. walls R-19 fiberglass batts in floor joists Floor over garage R-19 fiberglass batts in floor joists Infiltration testing 3.5 SLA 2.0 SLA NA 4 50 pa Glazing: Vinyl, dual pane Vinyl, dual pane U-Factor SHGC HVAC Heating system Gas furnace 0.80 AFUE Sealed combustion gas furnace 0.97 AFUE Cooling system 13 SEER/ 11 EER 19 SEER/ 13 EER Mechanical ventilation Duct insulation/ location Bathroom exhaust R-6 insulated ducts in unconditioned attic w/ 6% 25 pa ENERGY STAR exhaust R-6 insulated ducts in conditioned attic w/ 3.75 % 25 pa Water heating 0.58 Energy factor storage tank less gas 0.82 Energy factor tank less gas gas unit Lighting Incandescent ENERGY STAR CFL and LED light fixtures PV system None 34.1 kw AC system (38.7 kw DC) 1.9 kw AC per unit Appliances Dishwasher Standard ENERGY STAR Cooking range Gas Gas Refrigerator Standard ENERGY STAR HERS inspection/ testing HERSII rating 100* Typical Unit A 29 Typical Unit B 15 Typical Unit C 21 Typical Unit D 21 Duct leakage; building envelope sealing; cooling coil airflow & fan watt draw test; high EER equipment; refrigerant charge verification; maximum total cooling capacity; supply duct compliance credits; quality insulation installation 9

10 * By definition a new home or apartment built to the 2008 California Title-24 Standards receives a HERSII rating of 100. A home with a HERS index of 0 is a super-efficient Zero Net Energy Home that consumes no more energy than it produces with solar or other onsite renewable sources. Predicted energy savings NREL provided critical energy analysis assistance in the early stages of project design. The project team used NREL s BEopt (Building Energy Optimization) software, a computer program that helps determine the optimal building design for energy efficiency using California s Title 24 as the benchmark. Title-24 sets minimum energy performance standards for heating, cooling, water heating, and lighting for all buildings built in California and are considered the most stringent in the country. Additionally, BEopt includes estimates for appliances and plug loads based on Building America modeling protocols. NREL and DEG performed BEopt analyses of the four typical La Valentina townhomes, units A, B, C, and D. The BEopt analysis results follow below. Energy analysis using NREL s BEopt energy simulation software showed that the average townhouse would use 62% less source energy compared to the same townhouse built to California s 2008 Title-24 building energy standards for regulated end uses (heating, cooling, lighting, and water heating) and including estimates of miscellaneous plug loads and PV Production (base-case). The average townhouse is estimated to save 4,504 kwh, or 69% of annual electricity use, and 164 natural gas therms, or 38% of annual gas use, less than the base-case townhouse. Savings is estimated at $569 per year in annual utility bill costs (56% of annual utility bill). The average townhomes 4 to 7 p.m. summer peak electrical demand would be reduced 1.66 kw, or 71% from the base-case townhome (see Table 5 below)error! Reference source not found.. Table 5: La Valentina vs. Title-24 estimated energy use and utility bill savings unit % Source Energy Savings kwh Savings % kwh Savings Gas Savings Therms % Gas Savings % Peak Demand Savings Peak Demand Savings kw Bill Savings % Bill Savings A $ B $ C $ D $ Avg 62 4, $ A typical unit A was predicted to consume 63% less source energy, 4,553 less kwh and 109 less therms than its estimated base-case electricity and natural gas use, and its average 3-Day 4 to 7 p.m. Heat Storm Peak Demand is estimated to be 1.79 kw and 78% lower than the estimated base-case 3-Day Heat Storm Peak Demand 2. Tenants estimated annual electric and natural gas utility bills would be $521, or 53% less than the estimated base-case annual utility bill. These results are presented in Figure 1 through Figure 5 below. 2 SMUD s Resource Planning unit defines SMUD s peak period as the average 3-hour peak, 4 to 7p.m., recorded for 3 consecutive weekdays with temperatures over 105 F, typically occurring in July or August. 10

11 Figure 1: Estimated annual source energy savings Figure 2: Estimated annual electricity use savings 11

12 Figure 3: Estimated annual natural gas savings Figure 4: Estimated peak demand savings 12

13 Figure 5: Estimated annual utility bill savings A typical unit B was predicted to consume 59% less source energy, 4,478 less kwh and 206 less therms than the base-case electricity and natural gas use, and its average 3-Day 4 to 7 p.m. Heat Storm Peak Demand is estimated to be 1.6 kw and 66% lower than the base-case 3- Day Heat Storm Peak Demand. Tenants estimated annual electric and natural gas utility bills would be $606, or 57% less than the base-case annual utility bill. These results are presented in Figure 6 through Figure 10 below. 13

14 Figure 6: Estimated annual source energy savings Figure 7: Estimated annual electricity savings 14

15 Figure 8: Estimated annual natural gas savings Figure 9: Estimated peak demand savings 15

16 Figure 10: Estimated annual utility bill savings A typical unit C was predicted to consume 65% less source energy, 4,545 less kwh and 206 less therms than the base-case electricity and natural gas use, and its average 3-Day 4 to 7 p.m. Heat Storm Peak Demand is estimated to be 1.6 kw and 66% lower than the base-case 3- Day Heat Storm Peak Demand. Tenants estimated annual electric and natural gas utility bills would be $494, or 54% less than the base-case annual utility bill. These results are presented in Figure 11 through Figure 15 below. 16

17 Figure 11: Estimated annual source energy savings Figure 12: Estimated annual electricity use savings 17

18 Figure 13: Estimated annual natural gas use savings Figure 14: Estimated peak demand savings 18

19 Figure 15: Estimated annual utility bill savings A typical unit D was predicted to consume 59% less source energy, 4,545 less kwh and 206 less therms than the base-case electricity and natural gas use, and its average 3-Day 4 to 7 p.m. Heat Storm Peak Demand is estimated to be 1.6 kw and 66% lower than the base-case 3- Day Heat Storm Peak Demand. Tenants estimated annual electric and natural gas utility bills would be $607, or 58% less than the base-case annual utility bill. These results are presented in Figure 16 through Figure 20 below. 19

20 Figure 16: Estimated annual source energy savings Figure 17: Estimated annual electricity savings 20

21 Figure 18: Estimated annual natural gas savings Figure 19: Estimated peak demand savings 21

22 Figure 20: Estimated annual utility bill savings The project team also used EnergyPro software to document compliance with California s 2008 Title-24 residential building energy standards. Per the EnergyPro analysis, the La Valentina units on average would use 54.4% less TDV energy than a project built to the 2008 Title-24 Standards; including 63% less electricity and 48% less natural gas (see Table 6 and Table 7 below). 3 3 Note that Title-24 Estimated Savings only cover space heating and cooling and water heating energy use. 22

23 Table 6: La Valentina estimated energy savings: Title-24 vs. proposed design Unit Area sf Standard budget (2008 Title 24 Baseline) Per SF kbtu/sf-yr Per unit kbtu/yr Proposed budget (La Valentina) Per SF kbtu/sf-yr Energy reduction Per unit kbtu/yr % Unit A1 1, , , % Unit A2 1, , , % Unit A3 1, , , % Unit B1 1, , , % Unit B2 1, , , % Unit B3 1, , , % Unit B4 1, , , % Unit B5 1, , , % Unit B6 1, , , % Unit C1 1, , , % Unit C2 1, , , % Unit C3 1, , , % Unit D1 1, , , % Unit D2 1, , , % Unit D3 1, , , % Unit D4 1, , , % Unit D5 1, , , % Unit D6 1, , , % TOTAL 19,875 1,420, , % 1,420,130/ = ,065/ = Energy use intensity kbtu/sf-yr kbtu/sf-yr 23

24 Table 7: La Valentina estimated Title-24 standard design vs. proposed design electricity and natural gas savings Unit T24 Standard design Proposed design Margin kwh therms kwh therms kwh therms Unit A Unit A Unit A Unit B Unit B Unit B Unit B Unit B Unit B Unit C Unit C Unit C Unit D Unit D Unit D Unit D Unit D Unit D Total 15,916 6,284 5,806 3,289 10,075 2,999 Average Savings 63% 48% The building s 34.1 kw AC virtual net-metered solar photovoltaic (PV) system is estimated to generated 62,875 kwh per year, which is equally divided among the La Valentina tenants (3,308 kwh per townhome) under SMUD s virtual net metering rules. 4 4 SMUD conducts a pilot Virtual Net Metering program for qualified low-income projects that allows the building owner to equally parcel the production of a building s PV system to the tenants. 24

25 La Valentina construction La Valentina North included several innovative construction techniques that are highlighted in this section to explain the installation process and benefits. Air sealing and attic and wall insulation To achieve the ambitious energy performance goals of the project required an exceptionally tight building and increased insulation levels, especially in the buildings walls. The general contractor took extra steps to ensure that all joints and seams were sealed with either high performance caulking or spray foam (see Figure 21 through Figure 24 below). Figure 21: Spray foam, caulking wire, and piping penetrations Figure 23: Spray foam wiring penetrations Figure 22: Caulking joints Figure 244: Caulking joints 25

26 The attic was filled with 13 of polyurethane, open cell spray foam insulation (R-42) with radiant barrier roof sheathing (see Figure 25 and Figure 26). Figure 25: Radiant barrier roof sheathing Figure 26: Open cell spray foam Wall cavities were filled with R-15 dense pack, blown-in cellulose insulation (see Figure 27). An additional 1 of polyisocyanurate rigid insulation covered by 1 of EPS rigid foam insulation (R- 10 total) was installed on the external walls for a total wall insulation value of R-25 (see Figure 28 and Figure 29). Figure 27: Dense pack blown-in cellulose wall insulation Figure 28: 1 EPS rigid insulation over 1 Polyisocyanurate rigid insulation installed on outside walls 26

27 Figure 29: Completed External Rigid Insulation Heating, ventilation and air conditioning (HVAC) system La Valentina features a Honeywell TrueZone two-zone (upstairs/downstairs in two-story units), two ton American Standard SEER 19.25/EER 13 split system air conditioner and 97% AFUE sealed combustion condensing furnace with fresh air ventilation system providing fresh air through the return of the air handler (see Figure 30 and Figure 31 below). R-6 insulated HVAC ducts are located in the conditioned space. Figure 30: SEER 19.25/ EER 13 outdoor condenser Figure 31: 97% AFUE sealed combustion natural gas furnace 27

28 Lighting La Valentina s apartment unit and common area lighting both feature high efficiency lighting fixtures and lamps. The apartment s lighting package includes hard wired ENERGY STAR Cooper Lighting LED interior recessed down lights in hallways, kitchen, and bathroom and Lithonia ENERGY STAR linear flush mount T-8 fixtures in the kitchen. Bathroom vanity lighting is provided by Progress compact fluorescent lamps (CFL) fixtures. Common area lighting includes Progress ENERGY STAR CFL fixtures and Lithonia T-8 fluorescent strip lights in hallways. Water heating Domestic water heating is provided by Noritz ENERGY STAR 0.82 Energy Factor (EF) tank less natural gas water heaters (see Figure 32). Figure 32: Noritz ENERGY STAR 0.82 EF tank less natural gas water heater Solar photovoltaic (electric) system La Valentina is equipped with a 34.1 kilowatt (kw) AC photovoltaic (PV) system with Sanyo Power 210N HIT modules and Fronius I6 inverters (See Figure 33 below). The PV system will produce approximately 68,725 kwh of electricity per year, or 3,308 kwh/year per apartment unit. The La Valentina PV system is a Virtual Net Metered PV system in which the PV system s production output is divided equally among the La Valentina tenants. Virtual Net Metering (VNM) allows a multi-tenant building owner to install a single solar system to cover the electricity load of both common and tenant areas connected at the same service delivery point. The electricity does not flow directly to any tenant meter, but rather it feeds directly back onto the grid. SMUD then allocates the kilowatt hours from the energy produced by the solar PV generating system to both the building owners and tenants' individual utility accounts, based on a pre-arranged allocation agreement. The intent of VNM is to help low income multifamily residents receive direct benefits of the building's solar system, rather than all of the benefits going to the building owner. 28

29 Figure 33: La Valentina Solar PV System ENERGY STAR Appliances To save tenants both energy and money, Domus installed Bosch ENERGY STAR qualified 18.5 cubic feet refrigerators and dishwashers in the apartment units see Figure 34 and Figure 35 below). Figure 34: Apartment ENERGY STAR dishwasher Figure 35: Apartment ENERGY STAR refrigerator 29

30 Field verification and testing La Valentina underwent third party testing and inspection of the home s energy features to meet the requirements of California s Title-24 and Home Energy Rater (HERSII) program. Under California s Title-24 standards, third party testing and inspection is required of new homes to receive credit for various energy efficiency measures. La Valentina underwent the following Title-24 field verification & diagnostic tests: From the General Contractor and/or Installing Subcontractors: CF-6R ENV-01 Fenestration from Window Installer, General Contractor or Owner CF-6R ENV-20 HERS Building Envelope Sealing from Installing Subcontractor, General Contractor or Owner CF-6R ENV-21 HERS Quality Insulation Installation (QII) from Installing Subcontractor, General Contractor or Owner CF-6R ENV-22 HERS Quality Insulation Installation (QII) from Installing Subcontractor, General Contractor or Owner CF-6R-LTG-01 from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-01 Domestic Hot Water from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-02 Solar Domestic Hot Water from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-04 Space Conditioning Systems from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-05 Indoor Air Quality and Mechanical Ventilation from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-20-HERS Duct Leakage Test from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-22-HERS Cooling Coil Airflow and Fan Watt Draw Test from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-23-HERS Verification of High EER Equipment from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-25-HERS Refrigerant Charge Verification from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-27-HERS Maximum Rated Total Cooling Capacity from Installing Subcontractor, General Contractor or Owner CF-6R-MECH-28-HERS Low Leakage Air Handler Verification from Installing Subcontractor, General Contractor or Owner From the Home Energy Rater: CF-4R-ENV-20 Building Envelope Sealing from HERS Rater CF-4R-MECH-20 Duct Leakage Test from HERS Rater CF-4R MECH-21 Quality Insulation Installation (QII) CF-4R-MECH-22 Cooling Coil Airflow & Fan Watt Draw Test from HERS Rater CF-4R-MECH-23 Verification of High EER Equipment from HERS Rater CF-4R-MECH-25 Refrigerant Charge Verification from HERS Rater CF-4R-MECH-27 Maximum Rater Total Cooling Capacity from HERS Rater CF-4R-MECH-29 Supply Duct Compliance Credits - Location from HERS Rater 30

31 Red Tape Express, an independent, certified CalCerts, Inc. home energy rater (HERS), performed testing and inspections of La Valentina. Per Red Tape s testing and inspection, La Valentina achieved the following (see Table 8 & Table 9 below): Table 8: La Valentina blower door results Blower Door Results Unit Type Low High Tested Volume 50 pa A A A B B B B B B C C C D D D D D D Table 9: La Valentina HVAC duct leakage results Unit Tested Leakage (CFM50) HVAC Duct Leakage Results AC CFM 31 Duct Leakage (CFM50/AC CFM) A % A2 Not reported 800 A3 Not reported 800 B % B % B % B % B % B % C % C %

32 Unit Tested Leakage (CFM50) HVAC Duct Leakage Results AC CFM Duct Leakage (CFM50/AC CFM) C % D % D % D % D % D % D % Home energy rating As part of La Valentina s field verification and testing activities, La Valentina received a California Home Energy Rating System, HERSII rating. Under HERSII, a California State certified home energy rating system (HERS) Rater performed a comprehensive evaluation of the efficiency of La Valentina. HERSII is designed to provide an energy performance score for newly built and existing residential buildings. Under HERSII a home is rated on a scale of 250 to 0 with 0 representing a zero net energy home, or a home that uses as much energy as it produces. A home receiving a HERSII score of 100 uses the same energy as a new home that meets California s 2008 Building Energy Efficiency Standards. La Valentina was one of the first multi-family projects to receive a HERSII rating and achieve impressive scores, including the following; Typical Unit A - 29 Typical Unit B - 15 Typical Unit C - 21 Typical Unit D

33 Monitored Predicted Monitored Predicted Monitored Predicted Monitored Predicted Monitored Predicted Monitored Predicted kwh Long term monitoring SMUD engaged TRC to monitor post-occupancy energy use at the unit-level and compare it to simulated predictions of performance established during the project design and construction phase. TRC monitored six dwelling units representing at least one each of the four types of dwelling units at the property. Electric end-uses were monitored via a remote, web-enabled system called emonitor. Thermostats that communicate wirelessly with the emonitor system were installed in each monitored unit. Monitored data was collected for approximately 16 months, from summer 2012 to fall Overall electrical energy use for the six units monitored by TRC is higher by about 10% than predicted by the BEopt simulations done at the project design stage. The monitored energy use is about 17% less than the energy use for a Title 24 baseline building with similar geometry and size. The overall energy use for units is driven largely by the cooling energy use. Cooling energy use was predicted to be negligible (~9% of total unit electricity consumption) for this highly energy efficient building, however it ends up being about 30% of the total. Conversely the actual energy use for miscellaneous electrical loads is lower than predicted through simulations and what the Title 24 standards assume. Electrical energy use (overall and by end use) varies significantly by unit as is seen in Figure 36. Unit A-1 (most electricity consumption) uses almost 85% more electricity than Unit B-2 (least electricity consumption). This study indicates that more attention needs to be spent on actual energy use patterns and the causes for variation in actual energy use versus predicted energy use. Figure 36: Annual energy use by unit and end use (monitored versus predicted) 7,000 6,000 5,000 4,000 3,000 2,000 1,000 - Unit A-1 Unit B-1 Unit B-2 Unit C-1 Unit D-1 Unit D-2 Cooling HVAC Fan/Pump Vent Fan Lights Large Appliances Misc. 33

34 kw Unit A-1 Unit B-1 Unit B-2 Unit C-1 Unit D-1 Unit D-2 The photovoltaic (PV) system offsets ~65% of the electrical energy consumed across the six study units on an annual basis. The design of the PV system was for about 50% of building electrical demand so the PV system is working as intended. Even so, there is a big variation in how much energy use is offset by PV production by unit. Those units with overall low energy use have almost 90% of their energy use offset by PV production, however, most other units show the PV offsetting about 50% of their total energy use as seen in Figure 37 (or about as much as was expected). Figure 37: Annual kwh and Peak kw offset by PV A N N U A L K W H O F F S E T B Y P V 120% 100% 80% 60% 49% 52% 98% 79% 50% 58% 40% 20% 0% Heat Storm Aug 8-13 (Avg Outdoor High Temp 104 deg) % Peak Demand Reduction Net Apt (kw) Total Apt (kw) Total PV (kw) Combining the energy use and PV production, the building energy use is higher than predicted but within 10% of the predicted building energy use. The building performance during peak demand periods is admirable especially during the summer heat storms. As seen in Figure 37, the building had no peak impacts on the grid by offsetting the entire building electric peak demand during the heat storm with PV electric production. Thus the combination of energy efficiency and PV is working well. As noted above, monitored energy savings versus predicted energy savings varies greatly by unit, even after accounting for the PV output, as shown in Figure 38, below. 34

35 Figure 38: Project level energy savings summary A-1 B-1 C-1 D-1 Average Energy Savings (w/o PV) Monitored Predicted Monitored Predicted Monitored Predicted Monitored Predicted Monitored Predicted kwh Savings (%) -4% 25% 4% 24% 37% 25% 1% 24% 7% 24% Therm Savings (%) 70% 27% 23% 47% 60% 41% 29% 46% 39% 42% kbtu Source Savings (%) 45% 26% 17% 39% 51% 35% 19% 38% 28% 36% A-1 B-1 C-1 D-1 Average Net Energy Savings (with PV) Monitored Predicted Monitored Predicted Monitored Predicted Monitored Predicted Monitored Predicted kwh Savings (%) 47% 72% 52% 67% 85% 70% 49% 68% 56% 69% Therm Savings (%) 70% 27% 23% 47% 60% 41% 29% 46% 39% 42% kbtu Source Savings (%) 62% 42% 33% 54% 69% 51% 36% 54% 45% 52% Lessons learned Getting to zero net or near zero energy in multi-family is difficult but zero peak is achievable. The La Valentina project demonstrates the challenge of achieving zero net energy in multi-family housing. To achieve the Home of the Future 80% annual source energy performance goal would require an additional 24 kw AC of photovoltaics, or 1.7 times the size of the installed PV system; to achieve an annual zero net energy (a building that produces as much energy as it uses) would require a PV system almost three times bigger than the installed system, 92 kw AC. Even with impressive envelope and equipment upgrades, La Valentina only averaged a predicted 62% reduction in annual source energy savings. Of special note, it is particularly difficult to reduce the associated large natural gas energy end uses of space and water heating. Exceptional envelope features, including a very tight building, high insulation levels and 35

36 excellent windows were combined with condensing 95% AFUE furnaces with a duct distribution system installed in the conditioned space to reduce the project s heating loads, but even with these advanced efficiency features, the project s estimated heating energy use was only reduced 57%. A tank less, 0.82 EF gas water heater with short runs only reduced water annual heating energy use 41%. Solar heated water could reduce water heating energy use by more than 50% and make a major contribution to meeting the Home of the Future 80% annual source energy savings performance goal. But La Valentina s limited roof space and the low cost of natural gas made solar heated water difficult to implement as well as uneconomical. Reducing miscellaneous electric plug load energy use is also challenging since these are occupant controlled and not a permanent feature of the building. In theory the heating, cooling, water heating and large appliances should be reduced to the point that they are a minor energy use that can be met by the PV system. However, it is becoming increasingly difficult to achieve further reductions in these energy uses. More importantly, miscellaneous electric plug load energy use continues to grow as occupants purchase ever increasing numbers of electronic and entertainment appliances. Although La Valentina did not meet the Home of the Future 80% annual source energy savings performance goal, monitored data collected to date indicates that the La Valentina units will have lower peak demand than what was predicted by the BEopt analysis. Per the BEopt analysis, La Valentina s estimated peak demand is 71% less than its Title-24 compliant peak demand. Monitored data collected over an August 8-13, 2012 heat storm from 3 occupied units shows that peak demand savings exceed the BEopt analysis with 77%, 75%, and 114% average 4-7 pm peak demand reduction compared to monitored SMUD multi-family gas heated customers 4-7 pm peak demand (see Figure 39 through Figure 41 below). 36

37 Figure 39: La Valentina Unit B Aug 8-13, 2012 and SMUD Multi-Family, gas-heated customers average load (kw) profile 37

38 Figure 40: La Valentina Unit D1 Aug 8-13, 2012 and SMUD Multi-Family, gasheated customers average load (kw) profile D1 Figure 41: La Valentina Unit D2 Aug 8-13, 2012 and SMUD Multi-Family, gasheated customers average load (kw) profile 38

39 Using exterior rigid foam in multi-family is challenging. The original specification for the exterior rigid foam called for installing continuous exterior rigid foam with a staggered layer of 1 polyisocyanurate installed over 1 EPS with all seams taped. The La Valentina design team, general contractor, and stucco contractor were unfamiliar with installing exterior rigid foam and, as a result, were hesitant to use continuous insulation. In particular, La Valentina employed a three coat stucco cladding and all parties were concerned that the continuous exterior rigid foam specification would not be able to support the three coat stucco cladding. As a result, the designers came up with a specification in which the EPS and polyisocyanurate foam was cut into two foot sections with the polyisocyanurate installed over the EPS and the two foam pieces held in place by a metal z-clip (see Figure 42 below). La Valentina s design team estimated that the use of the metal z-clip would reduce the wall s U-Factor 6 to 10%, making the wall assembly effective R-value very similar to that for a wall with 1.5 of foam as opposed to 2, (approximately R-7.5), or a total wall R-Value would be reduced to R Figure 42: La Valentina wall assembly detail Foil face Polyisocyanurate rigid foam EPS rigid foam Metal Z-clip Multi-Family projects are difficult to rate under California s Home Energy Rating System (HERSII). California s Home Energy Rating System, HERSII, is designed to provide an energy performance score for newly built and existing residential buildings. Under HERSII a home is rated on a scale of 250 to 0 with 0 representing a zero net energy home, or a home that uses as much energy as it produces. HERSII ratings are calculated using inputs from the building s Title- 24 energy simulation. La Valentina was one of the first multi-family projects to receive a HERSII rating. However, California s Title-24 regulations are not sophisticated enough to handle some of the unique features found at La Valentina. Specifically, it was difficult to model La Valentina s 39

40 wall insulation assembly features into the Title-24 compliance software, EnergyPro 5. Quite simply, Title-24 only recognizes standard wall insulation assemblies, such as 2x4 walls with cavity insulation and 1 continuous exterior rigid insulation. It is unable to take into account a wall assembly that utilizes a metal z-clip such as the wall assembly used in La Valentina. As a result, an approximate R-value based on a more typical wall assembly had to be entered into EnergyPro and then entered into the Certificate software. The HERSII software then produced La Valentina s individual unit HERSII Certificates that showed inaccurate wall insulation R- values: for example, the Unit A HERSII Certificate showed R-22.4 wall insulation. The HERSII provider, CalCerts, explained that the approximate R-value used in the EnergyPro software resulted in a formatting error in the HERSII Certificate. Similarly, Title-24 requires that the photovoltaic system s energy production be entered into EnergyPro as TDV energy units, or Time-Dependent Valuation. In La Valentina s case, the correct TDV energy values for the La Valentina PV system were entered into EnergyPro but the HERSII Certificate was only able to show the TDV energy output of one of La Valentina s photovoltaic system s inverters. 5 EnergySoft s EnergyPro energy simulation software, EnergyPro, is the only energy simulation certified by the California Energy Commission to provide Title-24 compliant energy simulation documentation. 40