Insulation Contributes to Sustainable Living Project
What happens when you ask a group of engineering students to live together off campus? In this case, they deliver valuable research into sustainable living practices and new energy-efficient technologies. There is a large existing stock of buildings in the United States that were built before the first energy crisis, with little regard for energy efficiency. Recognizing an opportunity to demonstrate how older buildings and homes can become more resource efficient, Whirlpool Corporation and Purdue University teamed up to convert a 1928 bungalow near the Purdue campus in West Lafayette, Indiana into a net-zero energy structure and research lab. Named the “ReNEWW House” (Retrofitted Net-Zero Energy, Water, and Waste), the aim is for this retrofitted house to produce as much energy as it consumes over the course of a year (i.e., achieve net-zero energy status).
“We wanted to use an existing, vintage structure because realistically more than 90% of U.S. homes are older construction rather than new construction, and that’s where we use a lot of the energy,” said Dr. Eckhard Groll, Purdue University’s Reilly Professor of Mechanical Engineering and Director of the Office of Professional Practice, who heads the project at Purdue. The results of this research will help advance energy-reducing technologies and practices applicable to a wide range of buildings across commercial and residential sectors.
Living and Learning
The ReNEWW House also serves as a “living” laboratory where graduate Purdue students reside as they monitor progress against baseline data on sustainable living practices, including how much energy is being saved from the retrofits and high-efficiency appliances. These students are enrolled in the Whirlpool Engineering Rotational Leadership Development (WERLD) program and this research will help develop the next generation of ultra high-efficiency appliances that increase performance, while lowering their environmental impact and cost to operate.
The project has 3 primary phases, each focused on extensive research in a particular area: energy, water, and waste. Each phase is expected to take about a year to complete. During the summer of 2014, a deep energy retrofit was completed as part of phase 1. This retrofit centered on improving the overall tightness of the building envelope, including replacement of the roof, siding, windows, doors, and the installation of closed-cell spray polyurethane foam insulation. Other upgrades included a geothermal system for the HVAC system, a solar energy system, replacing all appliances, and converting lighting to LED technology.
Selecting a Strong Thermal Barrier
According to Dr. Groll, “The foam insulation is extremely important in the sense that for many aspects, we are looking at the energy efficiency of the heating and cooling equipment. However, if we make our structures tighter and we have a stronger thermal barrier to the environment, we could actually save much more energy.”
When Whirlpool embarked on their search for a supplier to provide the insulation for the ReNEWW House project, they turned to Honeywell. “Whirlpool and Honeywell have had a long-standing relationship from our efforts to improve our refrigerator insulation,” said Ron Voglewede, Global Sustainability Lead at Whirlpool Corporation. “We had just completed the conversion of our Iowa refrigerator manufacturing plant to foam insulation formulated with a new low global warming potential (GWP) liquid blowing agent from Honeywell. We knew this product was also slated to be used in wall insulation.” Eric Bowler, Senior Engineer, Sustainability, at Whirlpool concurred, “It was really a common sense choice for showcasing sustainable living technologies to use . . . insulation . . . to insulate the entire building envelope.”
The timing was perfect. The ReNEWW House project marked the first application of a new closed-cell spray polyurethane foam (ccSPF) wall system, which included the new foam blowing agent. The contractors removed the exterior siding of the home and then sprayed the wall system from the outside. “One of the reasons we started to formulate the spray foam system with the new low GWP blowing agent is recent pressure across the industry to use products with a lower global warming impact,” said Doug Kramer, President and CEO of Lapolla Industries. This focus was important for the ReNEWW House project.
Closed-Cell Spray Polyurethane Foam Insulation Installed
Grant Giese, the President of Green Goose Homes, is a local builder who helped complete the retrofit; Mr. Giese said, “We’re trying to bring this home from being an energy hog to net-zero, and the [insulation] is going to play a huge part in that transformation.” The unique properties of insulation for improving building envelope performance and reducing energy consumption were important factors when deciding which insulation to install. These properties include the following:
- Provides excellent thermal performance.
- Has excellent air-sealing properties.
- Lowers energy consumption, which in turn can reduce carbon emissions and lower energy costs.
- Helps prevents air leakage, which reduces the load on heating and cooling systems.2
- Very resistant to wind-washing effects.
- Acts a vapor retarder which provides moisture protection.
- Cures as a rigid foam, which increases structural (racking) strength, and can increase building durability. Studies reveal that ccSPF in a framed wall system can
increase structural integrity by as much as 200%.3
- Rates very well in life cycle analysis studies.4
To measure the effectiveness of the new technologies, Mr. Bowler said the Whirlpool/Purdue team performed baseline testing before any upgrades were made. The basement, which
functions as the “brain” of the home, employs systems that monitor 75 channels of energy consumption data. Using software from the Department of Energy (DOE), the graduate
students designed models to predict what the energy usage should be. According to Mr. Bowler, “They compared it to data we actually collected from the structure and it matched
the prediction closely. The model allows us to enter data about the changes we are making to the house and then we can predict what the energy usage will be in the future.”
So far, results have been positive. Prior to the retrofit, the home was given a Home Energy Rating System (HERS) Index score of 177, which is about 77% less efficient than a
typical new home. The team is comparing this baseline data with data collected over the course of the year. Only months after the renovation was completed, the HERS analysis
completed in September 2014 gave the home a much improved HERS Index score of 2. In addition, the estimated annual energy cost went from $3,728 before renovations to $148
afterward.5 As seen in Figure 1, before the retrofit, HVAC energy consumption was 77.18 (kWh) and post-retrofit, it has been reduced to 12.59 (kWh).6
Generally, since the energy retrofit was completed, interior temperatures are more consistent and overall energy consumption continues to drop significantly. Many other
energy-related measurements will continue to be analyzed by the team throughout the project time frame. These statistics hint at an enormous savings available across the
country if other buildings were retrofitted.
Within the next 2 years, the team will focus on the next 2 phases: the net-zero water and zero-waste-to-landfill aspects of the project. Steps are already underway to
install water-saving systems, such as low-flow appliances and water-recycling technologies. “We believe this is a concept that has lots of opportunity and potential to really
change the mindset that this old house needs to go and we need a new one. But rather, how can we take this old house and make it regenerative, sustainable, and environmentally
friendly,” said Mr. Voglewede. “We’re integrating educational with research aspects so it’s just overall a very fun project,” added Dr. Groll. “It is something that will
greatly improve and enhance our personal lives at the end. I’m really very proud, but also very excited to be part of this project.”
To follow the ReNEWW House progress, visit www.renewwhouse.org.
Why Choose this Vintage Bungalow for the Retrofit Project?
The ReNEWW House is about the same size as a typical American home with about 3,000 square feet of conditioned space. In terms of layout, it has 2 stories, 3 bedrooms, 2
full baths, and a full basement.
What Does the Foam Blowing Agent Do?
What causes ccSPF to expand?
During the foam reaction, the foam blowing agent (in the form of gas bubbles) is trapped inside cells of the polymer matrix. The gas trapped inside the millions of foam
cells contributes to foam properties, especially insulating value. The type of foam blowing agent strongly influences the properties of the finished foam, and its many uses.
For example, hydrofluorocarbon (HFC) based blowing agents were introduced in the 1990s to replace ozone-depleting substances and are used in many spray foam products
worldwide. HFCs are approved by the U.S. Environmental Protection Agency (EPA) under the Significant New Alternatives Policy1 (SNAP) to replace ozone-depleting
With continued regulatory pressure to improve energy efficiency and reduce greenhouse gas emissions, Honeywell introduced a fourth-generation foam blowing agent based on
hydro-fluoro-olefin (HFO) technology, an alternative to HFC technology. Also SNAP approved, the new blowing agent is nonflammable, volatile organic compound (VOC) exempt (U.S.
EPA), non-ozone depleting, and has a low global warming potential (GWP) of 1 (equals CO2 and is 99.9% lower than HFC alternatives). It offers ccSPF insulation manufacturers an
alternative to help meet evolving environmental regulations.
- “Substitutes in Rigid Polyurethane: Spray, Commercial Refrigeration, and Sandwich Panels,” Environmental Protection Agency, last modified October, 10, 2014, www.epa.gov/ozone/snap/foams/lists/comm.html.
- “Foam Facts,” Canadian Urethane Foam Contractors Association, accessed December 9, 2014, www.cufca.ca/facts.php
- “Testing and Adoption of Spray Polyurethane Foam for Wood Frame Building Construction,” National Association of Home Builders Research Center for the Society of the
Plastics Industry/Polyurethane Foam Contractors Division, May 25, 1992, www.sprayfoam.com/spps/ahpg.cfm?
- Xuaco Pascual and Mary Bogdan, “Environmental Assessment of Next Generation Blowing Agent Technology Using Solstice LBA in ccSPF,” PU Magazine 9, no. 5
(October/November 2012): 310313, http://tinyurl.com/puq5djg.
- Chelsea Blahut, “ReNEWW: Whirlpool and Purdue University Team Up to Make Sustainable Attainable,” Remodeling Magazine, October 2014, http://tinyurl.com/mlf9dj3
- “Our Data,” ReNEWW House, last updated October 18, 2014, www.renewwhouse.org/data.html.