WEST LAFAYETTE, IND. — A select few students at Purdue University now get to call an upgraded, energy efficient late 1920s vintage bungalow, “home.” Whirlpool Corporation engineers are working with Purdue University to transform an off-campus house into a net-zero energy, water and waste structure. Called ReNEWW house — Retrofitted Net-zero Energy, Water and Waste — the house received energy improvements starting in 2014.
The ReNEWW House is an off-campus house that started out as a “living lab” where talented individuals involved in the Whirlpool Engineering Rotational Leadership Development (WERLD) program could perform research in partnership with Purdue while they pursue their master’s degrees in engineering. Whirlpool Corporation engineers who participate in the WERLD Program and are enrolled in the engineering graduate program at Purdue University will have the option to live and work in the house.
“WERLD students who work in the house perform research in a variety of multi-disciplinary projects, receive formal mentoring and training, and work with some of the world’s most innovative systems and technologies. Some students focus on the renewable energy side, while others are interested in learning about water reuse. Professors actively help and work alongside engineers on their programs,” says Jason Schneemann, project engineer, Sustainability, Whirlpool Corporation.
The components installed in the house were split up in multiple phases. The first phase, completed at the end of 2015, focused on energy capture and retrofitting the home to include systems and materials such as Enertech Global geothermal systems, which was installed to heat and cool the house, and has separate temperature control zones for the basement and the main floor, solar paneling from Eco Green Energy — formerly Solarzentrum — low GWP insulation and triple-panel windows.
Subsequent improvements focus on water-saving renovations, including a greywater system that uses reclaimed water from sinks and showers. The second phase of the project focused on updating the house’s water systems to achieve the goal of net-zero water.
The team installed a rainwater system, designed by Bob Boulware at Design-Aire Engineering (DAE), that captures rainwater from the roof and an interior system that filters water for drinking water usage; and implemented water reuse systems, including shower-to-toilet greywater recycling and energy-efficient systems, designed for the home by Clean Blu.
Whirlpool worked with Kohler, which equipped the house with water-efficient toilets, faucets and showers. During this second phase, a new suite of energy- and water-efficient Whirlpool brand appliances were also incorporated.
“Whirlpool had begun the net-zero energy phase and they were interested in partnering with us on the net-zero water phase, so we worked with our internal team to create a proposal to renovate the home with all Kohler products and determine the parameters for gathering data and setting measurement criteria,” says Carl Schroeder, senior new product development program manager, Kohler.
Initially, Whirlpool’s concept was a demonstration house, showing the potential to convert an old house to a net-zero footprint, which has been rarely done as most net-zero houses are new construction. In the energy phase Whirlpool had outfitted the house with sensors to collect data on energy use/efficiency.
“We proposed outfitting the home with temperature and flow sensors to monitor use patterns and thus better understand how resident behavior impacts water consumption in combination with products designed to use less water,” says Schroeder.
Moreover, engineers installed an instrumentation system that monitors key data and employs data collected to help develop next-generation, high-efficiency appliances in conjunction with Purdue University.
Kohler products for the house were chosen based on water-saving potential and designs that fit well with the Craftsman style of the home. “The first-floor bathroom, with the Poplin Vanity and Memoirs faucets, uses a neutral color palette accented with oil-rubbed bronze accessories, which complements the home’s original woodwork. The second floor bathroom includes the Jacquard Vanity and Archer faucets with neutral white and greys,” says Stephanie Marshall, senior project designer, Kohler.
The data shows the home’s water usage has significantly decreased after the installation of KOHLER water-saving fixtures and Whirlpool appliances, from 103 to 34 gallons per day. The reduction includes 70 percent less toileting water, 50 percent less showering water, 63 percent reduction in laundry water, and 18 percent less kitchen use. The upstairs bathroom is the largest area of water consumption.
Since the ReNEWW House focuses on three aspects: net-zero energy, net-zero water and net-zero waste, success in each area depends on proper collection, storage, consumption and reuse.
According to Bill Kuru, engineer, Kohler, a fundamental challenge associated with “net-zero energy” for older homes is maximizing the collection and storage of energy.
“Engineers have solutions for many technical issues, but a few obstacles are difficult to overcome in existing homes,” said Kuru. Solar arrays require suitable space to maximize energy capture, and older homes may have trees that prevent energy collection during parts of the day. Also, the local climate plays a huge role. “It’s important to note that the home is considered ‘net-zero energy’ over the course of a full year,” says Kuru.
The ReNEWW House is in a heating climate with many cloudy days, so the home underwent a massive energy retrofit to address energy consumption and storage. This included new insulation, heating system, water heater, lighting, windows, doors, siding and roofing.
In addition, a drainline heat recovery system was added to recover waste energy from the shower drain and use it to heat incoming cold water. Each shower has a drainline heat recovery system. In an older house like the ReNEWW house, the challenge was finding adequate space under the shower for a properly sized system to make the energy recovered worth the investment.
To make the ReNEWW House “net-zero water,” all plumbing fixtures were changed to high-efficiency Kohler fixtures, all appliances were switched to high-efficiency Whirlpool appliances, and two water collection and treatment systems were installed: one for rainwater, and one for greywater. Rainwater is collected from the solar panels, stored, treated, and pumped into the home’s plumbing system. The solar panels installed are designed to melt snow and supply water to the house.
This was a challenge to “net-zero energy” in that electrical energy is required to melt the snow to produce water. Rainwater is stored in tanks underground, so the team needed to find a location for these tanks next to the home. Greywater is collected from showers, treated, and pumped to the toilets. There are technical challenges associated with treating and using greywater.
Kohler toilets are warranted to use greywater as long as it meets NSF 350 third-party performance standards for small onsite greywater systems. As with net-zero energy, the local climate plays a huge role in net-zero water. The ReNEWW House is considered “net-zero water” over the course of a full year, meaning that all water used in the home is either captured onsite or treated and reused. Wastewater is, however, still being discharged to the municipal sewer.
Preserving history & replication
Upgrading the home didn’t come without other challenges. “There were multiple challenges in retrofitting a 1920's home,” says Schneemann. “The first was respecting the home's historical integrity. This presented both a challenge and an opportunity. It meant that we could not fundamentally alter the home's layout or outside appearance beyond what was approved by the historical society, and had to be very creative in how to implement improvements.”
In regards to the water retrofit, since this home sits on a typical small city lot, positioning and connecting the outdoor water systems — roof to filter, filter to cisterns, cistern to house — proved very difficult. “However, all specs of the system were able to be implemented as designed — again, creativity was key,” says Schneemann.
It is the hope that specific technologies and methods from the ReNEWW house could be used in different areas of the country, where they are most effectively utilized.
“We recognize that to further extend the benefits of water-efficient fixtures and faucets while maintaining optimum performance, we need to look at home water consumption holistically,” says Rob Zimmerman, Kohler Sustainability senior channel manager. “We hope that by combining our engineering resources with those of Whirlpool’s to understand the technical challenges of creating a ‘net zero water’ house, we can develop new insights for designing home plumbing, water storage and treatment systems that further reduce water use and better protect our water supplies.”