NetZero Village - NY Capital Region

NetZero Village - NY Capital Region

David Bruns is changing the way developers look at energy efficiency by proving that a net zero apartment development could be commercially viable in the extreme weather of the Northeast. Building netZero Village combines developer David Bruns’ three passions: engineering, energy efficiency, and residential real estate. His design is based on Passive House concepts, using careful analysis to predict energy consumption. The object was to achieve the long-term equilibrium between energy demand and supply that constitutes net zero energy performance, in which the renewable energy production offsets the energy consumed by the buildings.

 

 

Project Team Profile

David Bruns – Developer, Bruns Realty Group, LLC
An engineer by trade and involved with multifamily housing management and development for more than 25 years, David Bruns has long been fascinated by the advances in energy efficiency technology. This was the driving motivation for creating netZero Village—a recently completed, 156-unit, apartment complex in Rotterdam, NY. After realizing that net zero energy building had not been wholly introduced to the multifamily housing market in New York, Bruns was determined to engineer buildings using the latest in proven, energy-efficient technologies. netZero Village incorporates the use of photovoltaic solar panels for electricity, solar thermal panels for the domestic hot water system, and an overall passive solar design, which uses the sun’s energy for heating and cooling living spaces.

Jesse Schwartzberg – Energy Consultant, Black Mountain Design Build (BMDB)
Jesse Schwartzberg currently holds LEED AP accreditation and is a licensed architect. Combining his master’s degree in architecture from the University of Oregon and six years of experience as a finish carpenter, he founded BMDB in 2011. BMDB specializes in high-quality, regionally focused design; high-performance energy consulting; and ecologically sensitive landscape design.

Green Hammer – Energy Modeling Consultant
Green Hammer, an Oregon-based firm, specializes in high-performance building design and consulting. They offer energy performance analysis and building envelope strategy to project teams looking to achieve Passive House, Living Building Challenge, and/or net zero energy performance.

Eric Carlson – Builder, Ballston Mourningkill Associates, LLC
As a net zero energy builder and developer, Ballston Mourningkill Associates, LLC were excited to be part of the team for netZero Village. Since 2007, they have provided turn-key services, including design, development, office space construction and management, warehouse space, residential subdivisions, and more than 400 apartment units throughout the Capital Region.

Tom Vitale – Home Energy Rater, En-Tech Associates Inc.
En-Tech Associates has more than 20 years of experience in the industry and nearly 15 years of training and experience in the building performance field. They focus on improving energy efficiency and reducing maintenance expenses, which pass savings on to builders and homeowners. En-Tech offers services for residential, multifamily, and commercial facilities.

Monolith Solar (Solar Electric), Designer, and Installer
A Capital Region company established in 2008, Monolith began by putting solar on their own houses. They moved on to powering the Rensselaer Library, as well as Union College and other commercial properties in the capital region. Nine years later, those solar planes remain in place. Monolith continues to grow and has produced 60 million kWh on their systems to date.

E2G Solar (Solar Hot Water), Designer, and Installer
E2G Solar specializes in custom designed solar hot water systems for commercial applications and large residential installations. Their expertise in design, engineering, and installation of solar hot water allows them to elevate their profile and respect within the industry. They educate the community through outreach and workshops and have also published a textbook on solar hot water.

Project Team:

DEVELOPER

Bruns Realty Group, LLC Inc

 

David Bruns

ARCHITECT

Harris A. Sanders, Architects, P.C.

Daniel P. Sanders

GENERAL CONTRACTOR

Ballston Mourningkill Associates LLC

Eric Carlson

HERS RATER

En-Tech Associates Inc

Tom Vitale

ARCHITECTURAL AND ENERGY DESIGN CONSULTANT

Black Mountain Design Build (BMDB)

Jesse Schwartzberg

SOLAR ELECTRIC

Monolith Solar

Mark Fobare

SOLAR HOT WATER

E2G Solar

Peter Skinner

ENERGY MODELING CONSULTANT

Green Hammer

Dylan Lamar

 

Net Zero Strategy

Bruns Realty’s strategy for netZero Village is based on Passive House principles, which promote an airtight building envelope by combining continuous insulation and high-performance windows with heat recovery ventilation and passive control of solar gains through building orientation and integrated shading.

From the ground up, the design of netZero Village emphasized the strategic use of insulation. The team installed rigid board insulation underneath the building’s slab and around the foundation’s perimeter. The seams between insulation boards are taped to stop air movement as well as water vapor and bulk moisture from wicking up though the slab. The above-grade walls are wood framed; 12 inches on center on the first floor for structural integrity and 24 inches on center on the second and third floors to reduce thermal bridging. ZIP System® wall sheathing was used as a weather resistive barrier and provides a continuous insulation R-value of 3. The wall cavities are insulated to R-22 with high-density spray foam for a total R-value of 25 for the wall. The flat wood truss roof uses a combination of ZIP System sheathing and spray foam as well. Roughly three inches of low-density spray foam are applied to the underside of the roof sheathing and four inches of continuous polyisocyanurate insulation are installed on the roof deck for a total roof R-value of 41.

All wall and roof seams of the ZIP System® sheathing as well as plumbing and electrical penetrations are sealed to create a continuous air barrier. The project team conducted a pre-insulation air-leakage test early in the process on the first building to help educate the framing team on projects goals and visually demonstrate critical building intersections to look for while air-sealing. By filling the building with theatrical smoke and then pressurizing it, they identified and corrected any remaining leaks where smoke escaped though unintended gaps. When the finished building was tested again, it exceeded the project team’s self-imposed Passive House level tightness target of 0.6 ACH50. Additionally, individual dwelling units were tested to determine how well they were isolated from one another. They all exceeded the Low-rise Residential New Construction Program’s limit for compartmentalization of less than 0.3 CFM50/square foot of surface area. This level of detail to separate living spaces is critical in multifamily dwellings where air leaks between units can facilitate the spread of cooking odors, pests, and indoor air pollutants like smoke.

To ensure healthy indoor air quality by optimizing the fresh-air intake throughout the units, the project team decided to install Heat Recovery Ventilators (HRV). An HRV is a balanced ventilation system, which in cold weather, extracts heat from air being exhausted out of a home and transfers that heat to filtered, fresh air being drawn in. In the warmer months, the system works in reverse. In addition to proper ventilation, the project team intentionally minimized the pollutants introduced to the space by using non-toxic finishes like low-VOC paint, Green Label Plus carpeting, and larger snap-lock hard flooring. netZero Village earned the U.S. EPA’s Indoor airPLUS certification for the quality of the indoor environment.

Windows are also an important part of the high-performance approach. The buildings at netZero village are oriented due south with more than 80 percent of the glazing located on the south façade to maximize solar gains and natural light. They chose to install double pane windows only, but used an additional low-e coating layer to increase resistance to heat loss. By designing higher ceilings and installing windows with high solar heat gain coefficients, natural light can stream in maximizing warmth from the sun on cold, winter days. In the summer when the sun is positioned higher, direct rays are blocked by the permanently mounted awnings located over each window to prevent overheating while still providing plenty of daylight.

The combination of a tight, well-insulated envelope with HRV and passive solar strategies resulted in very low heating and cooling needs, making it possible to use simple, single-head ductless mini-split air source heat pump systems. However, since only one indoor fan coil (the inside component of a heat pump) is used, located in the open-concept space of each apartment, there was a need for further distribution. An additional small inline fan was installed to distribute warmed or cooled air though a duct to each bedroom. Furthermore, a careful comfort analysis by Steven Winter Associates determined that additional back-up heat would be necessary to ensure year-round comfort in the bedrooms. A 500-watt electric baseboard heater was installed in each bedroom. Instead of relying on the occupants to control this supplemental heater, the process has been automated in conjunction with the air transfer fan, with temperature sensors located in the living room as well as in each bedroom. As soon as the sensors recognize a 1°F difference in temperature across the two spaces, the transfer fan is activated. If the temperature difference persists for 30 minutes, the electric baseboard is automatically turned on.

Rather than add to the electric load of the building for domestic hot water, the project team used a central solar hot water system with electric back-up capacity. The anticipated diversity of hot water use by residents over the course of each day was incorporated as part of the strategy related to use of an efficient centralized hot water systems, including connecting the storage tanks between two 6-unit mechanical rooms located in each building. A circulator will turn on if the temperature in one of the tanks falls below a threshold prior to the electric resistant back-ups becoming energized. Each group of the six dwelling units rely on seven dedicated solar hot water panels located on the roof of the building, paired with a large 1,000-gallon custom-built heat exchanger tank in the first floor mechanical room. To distribute hot water to each of the units, the team chose an efficient yet simple distribution approach; a main trunk delivers water to each unit and from there, short “home-runs” are used to reach each fixture within the dwelling. This method worked well for reducing hot water waste in part because the water-using appliances as well as the kitchen and bathroom(s) are located close together at the rear wall of the apartment. netZero Village features all ENERGY STAR® appliances and LED lighting, which further contribute to the low electric demand of the project.

Additionally, a Solar Electric generation system was incorporated to achieve net zero energy performance. The solar photovoltaic collectors are on ground-mounted structures and form the roof of the car ports. The output of the solar arrays also serves the common areas and the excess electricity powers the car charging stations installed for tenant use at no additional cost.

Taitem Engineering was engaged to deliver commissioning and energy consumption analysis services. Taitem completed a commissioning plan and carried it out to verify the performance of various systems. Now that the units are occupied, they’ve been monitoring energy use and comparing the actual usage to that predicted by the energy modeling software used during the design phase. Taitem, Bruns, and NYSERDA hope to use the results to inform future design improvements.

Economics

 

The netZero Village project team used several innovative approaches to keep the project cost effective while achieving the ambitious goal of net zero energy performance. Most significantly, they applied an integrative design model to their team work and engineered important building components, considering both cost and performance. They developed a matrix to compare various options for each building component; a code compliant baseline, along with options identified as good, better, and best. Using Passive House modeling software, they assessed the energy impact of each and decide if added costs were justifiable or unnecessary. An example created for window selection purposes is illustrated in the following table.

BUILDING COMPONENT

BASELINE

ENERGY EFFICIENCY MEASURES

GOOD

BETTER

BEST

Windows

2-pane, Lo-e

2-pane, Lo-e, Argon

3-pane, Lo-e, Air

3-pane, Lo-e, Argon

Details

U – 0.29

SHGC – 0.31

U – 0.26

SHGC – 0.65

U – 0.18

SHGC – 0.54

U – 0.09

SHGC – 0.50

Annual Savings kWh

N/A

10,573

11,880

15,119

 

In this case, the project team selected the “good” option because it offered the level of savings they were looking for, more than 10,000 kWh/yr, while being significantly less expensive than the triple pane windows that represented the “better” or “best” options.

Bruns’ team developed less conventional methods to reduce costs on individual measures by thinking outside the box. One example is their use of a six-inch buffer of sand to protect the continuous slab insulation from damage, ensuring concrete placement could occur in a conventional manner without additional and time-consuming precautions. This technique, in addition to placing all plumbing penetrations toward the back of the building, allowed for fast, efficient placement of the slab. Another example of innovation is the shop-built awnings installed over the windows in lieu of more expensive commercial exterior shading structures. The team hired a local contractor to manufacture the shades using affordable, “off-the-shelf” vinyl fence rail.

The layout at netZero Village contributed to savings beyond the benefits of passive solar design. The mechanical rooms are stacked and located at the core of each set of the six dwelling units. Systems like the HRV units, air transfer fans, domestic hot water tanks, and electric distribution are all contained within this central space. This arrangement allowed for hot water distribution efficiencies—they used smaller diameter water piping than would otherwise be required, making the home-run layout possible. Additionally, access from the common space to the centrally located systems allows for regular maintenance and repair without disrupting tenants.

netZero Village’s energy-efficient design benefitted the developer both during and after construction. The tight envelope kept the heating demand low throughout the winter months even though cavity insulation had not yet been installed during that phase of construction. Two ductless mini-split air source heat pump systems were sufficient for keeping six apartments warm simultaneously and used supplemental heat minimally. Because of this, heating the buildings during the winter months of construction was significantly less expensive than expected and resulted in substantial savings.

Bruns Realty’s business model is to offer their tenants a flat rate for utilities including heat, air-conditioning, hot water, sewer, trash, internet, local TV, and electricity at a lower cost than they would incur if they purchased these services individually. The convenience and savings of this attractive offer contributed to the rapid lease-out rate. According to Bruns, the dwelling units were rented in less than half the time it would have taken for a conventional project. Because of the savings they realize due to extreme efficiency, Bruns Realty is able to include utilities without concern over a few high users. In fact, incorporating solar electric and having a Power Purchase Agreement (PPA) makes this model profitable to the point where they even offer two complimentary electric car-charging stations.

To help keep their tenants informed, installed monitors in each lobby display how much energy the apartments are consuming anonymously in real time. Although they do not identify the corresponding apartment number or tenant names, this behavioral feedback system gives residents a sense of how they are using energy as a whole. This same constant digital monitoring system allows Bruns to track energy use by apartment and helps identify issues, like malfunctioning equipment, as they arise.

Solar electric coupled with building efficiency allowed Bruns to access incentives though NYSERDA’s Low-rise Residential New Construction Program and NY-Sun Program. The project earned up to $4,000 in builder incentives per dwelling unit for exceeding the program’s Tier 3 requirements. They were also eligible for a $2,000 tax credit per dwelling through the Energy-Efficient New Homes Tax Credit for Home Builders. Please note that tax credit and incentive levels change due to market transformation trends, changing code requirements, and advancements in technology. Visit NYSERDA’s website for more information on Low-rise Residential New Construction Program.

Lessons Learned

All of the buildings at netZero Village are oriented due south. This arrangement is necessary for the passive solar features to function as designed; however, it caused a four-month delay in the permitting process because the town planning board would not approve the initial site plan due to aesthetic concerns. Bruns made compromises with building arrangements that better suited the town’s requests, but still maintained the passive solar design.

On a higher level, Bruns plans to apply some techniques differently on future projects. This includes moving away from shallow buildings to double loaded corridors. Although this would reduce his opportunity for capturing passive solar gains, having a more compact building with a better surface area to volume ratio is a trade-off in efficiency. Bruns is confident that he will continue to reach net zero energy performance without the need for additional PV capacity. Additionally, netZero Village is sub-metered for electricity, which means each apartment unit has its own electric meter and will receive individual bills from the utility even though the cost is included in the rent. It was set up this way to reduce the risk of demand charges that can occur when commercial customers have a large spike in energy use, which requires the utility to increase production to meet demand. Spikes in energy use in multifamily buildings might occur if, for example, all residents were cooking or using their air conditioning at the same time. Based on the greatly reduced heating and cooling loads as well as the energy demand and usage patterns of his tenants, Bruns reasoned that if the project were master metered, demand charges would not be an issue. Residents tend to use their appliances or hot water during differing times of the day due to the variety of lifestyles and schedules. On future projects, Bruns plans to use a less costly master meter arrangement now that he has a clear understanding demand charges.

Homeowner Experience

Beyond including all utilities, covered parking, and available electric car charging; residents cannot provide enough positive praise to the completed community. Many 4 to 5 star reviews from verified residents were received on Apartmentguide.com:

  • “The apartments are beautiful, modern, and spacious. Maintenance requests are incredibly simple as well!”
  • “netZero Village uses solar energy to make luxury apartment living both affordable and eco-friendly. The owner and staff are friendly and go above and beyond to make your rental experience absolutely perfect. I was one of the first tenants to move in and do not foresee myself ever wanting to leave. This is by far the BEST apartment complex in the area.”
  • “This place is great for people who love modern living. Updated appliances!”
  • “Apartments are lovely. The finishes and the appliances are first rate. Apartments are sunny and spacious. Rooms are really good size and the walk-in closet in the master bedroom is fantastic! The attention I received when I have any need and/or question is beyond anything I have ever experienced with the rental situation. I also love knowing that my living here I am doing my part to perhaps make environment better for my grandchildren!”

Pictures, Plans, Materials

Size: 838 – 1057 square feet

Stories: 14 three story building with 12 dwelling units each          

Bedrooms: 1-2

Baths: 1

Climate Zone: 5

HERS Index : Pre-PV: 46 and Post PV: 7

Performance Features

Walls: R-value 26, Composition: R-value 3.6 ZIP System wall sheathing continuous, R-value 22.4 spray foam cavity insulation; 2x6 @ 24” O.C framing

Roof: R-value 41, Composition: flat roof with low-density spray foam, zip sheathing, and polyisocyanurate; covered with EDPM

Foundation: Slab on grade; R10 underslab, R11 perimeter

Windows: U-Value 0.24, SHGC 0.28 / Composition: Double glazed, Low-e Argon.

Whole Building Air-Sealing: ACH 50: less than 0.6 CFM50. Strategy: ZIP System wall sheating and spray foam; in progress air-tightness testing; individual units tested out at an average of 0.16 CFM50/square foot of surface area; less than their initial goal of 0.3 CFM50/square foot of surface area.

Duct-sealing: Ductless mini-splits

Ventilation: Continuous

Type: Heat Recovery Ventilator, Venmar AVS model number 44102, Energy Star Efficiency: 77% per cut sheet Distribution: Ducted, stand alone

Space Conditioning: ASHPs inverter driven mini splits plus 500W electric baseboard backup Efficiency: HSPF 12.2, SEER 21.5

Hot Water: Central Solar Thermal System - drain back; 80 Gal electric .91 EF tank heaters for backup

Lighting: 100% LED

ENERGY STAR-Rated Appliances: ALL ENERGY STAR appliances

Solar: 5 kilowatt ground-mounted car-port photovoltaic system (solar electric)

Water Conservation Strategy: Trunk and Branch, then homerun distribution system within each unit

Certifications: New York ENERGY STAR Certified Home, EPA Indoor AirPlus

Green features:

  • Electric Car Charging Stations. Free to residents – 100% solar powered
  • EPA Indoor AirPlus certified
  • Built to Passive House Institute specifications (not certified)