A Deep Energy Retrofit Brings ReNEWW House HERS Score to Near Zero

The first phase of the ambitious ReNEWW House project has slashed this home’s HERS score to near zero.

In July 2013, Whirlpool Corporation partnered with Purdue University on a retrofit of a late 1920s bungalow in West Lafayette, Indiana. The goal: to create more livable spaces while lowering operational costs and environmental impacts.

The ReNEWW house includes 2,864 sq. ft. of conditioned space, three bedrooms, two baths and a basement laboratory.

Called the ReNEWW house, for Retrofitted Net-zero Energy, Water and Waste, the structure will be renovated in three phases, with each phase lasting roughly a year. Phase one, a deep-energy retrofit, was completed in the summer of 2014.

On Sept. 12, 2014, the house officially opened as a “living lab.” “Originally, we partnered with Whirlpool to establish a graduate co-op program where four engineering students would split their time between six-month rotations at Whirlpool and two semesters at Purdue,” says Eckhard Groll, the Reilly Professor of Mechanical Engineering and director of the Office of Professional Practice at Purdue University. “This was the foundation for the ReNEWW House, as it provided a living dynamic in which to get real world data.”

Up to three graduate students participating in the Whirlpool Engineering Rotational Leadership Development (WERLD) program will live there throughout the project. They and Purdue researchers will monitor more than 70 data points inside and outside the home to evaluate its performance.

Answering a Need

One goal of the ReNEWW project is to demonstrate the feasibility of renovating a 1920s home to meet or exceed new home efficiencies, while maintaining all the charm and character of an older home.

“There are a lot of examples of net-zero energy homes; almost all of them are new builds,” says Eric Bowler, senior engineer and ReNEWW House project manager for Whirlpool Corporation. “The fact is, this country’s inventory of building stock stands at approximately 130 million units. If we really want to reduce the dependence on foreign energy resources, we need to look at retrofits.”

While there are several academic programs in the U.S. that utilize net-zero energy homes for research purposes, these homes are typically new builds and vacant, says Groll. Living in the home allows students to realistically replicate the impacts residents have on their homes.

Phase One: A Deep-Energy Retrofit

Green Goose Homes, a builder in the Lafayette, Indiana, area that focuses on using advanced techniques and products to build resource-efficient homes, served as the ReNEWW House’s general contractor, providing jobsite supervision and management. Several leading building materials manufacturers are also helping to take this 84-year-old home into the future (see sidebar below).

The laundry pair includes the Whirlpool Duet HybridCare clothes dryer, which regenerates energy during the drying cycle to reduce overall energy consumption.

Prior to the start of the project, the ReNEWW House received a 177 HERS rating with an estimated annual energy cost of $3,728. Three months later, with the deep-energy retrofit completed, the house was reevaluated and received a HERS rating of 1. The post-renovation estimated annual energy cost is just $126.

This tremendous improvement did not come as a surprise to Bowler. “To establish a baseline, we installed numerous thermo couples, relative humidity sensors, water and gas flow meters and an electricity monitoring system,” he says. “The data gathered offered us the ability to create and validate a simulation of the home’s energy consumption to predict efficiencies based on upgraded materials, appliances and fixtures in isolation or as an integrated system.”

Looking Ahead

As Whirlpool Corporation and Purdue University work together toward phases two and three of the ReNEWW House project, researchers will continue monitoring temperature, relative humidity and energy consumption, Bowler says.

Eckhard Groll wants to take it one step further: “One thing we want to create is a tool box for homeowners to look at all components of the home and identify the savings over time. The goal is to bring the level of sophistication of the automobile to the home. In a car, sensors closely monitor road conditions and make adjustments, and engine diagnostics alert drivers when repairs may be needed. In the home, most people only know if the air conditioner or furnace is running or not.”