These Homes Cash In On Design For Lower Cost, Better Performance

A rift valley is by definition a long valley where the land has sunk down between parallel faults. There is a rift valley on the Rio Grande in the desert of New Mexico where an award-winning home sits.

This LEED Platinum home designed by two former industry professionals as their forever home represents the rift between commercial construction practices and best in class, demonstrating what can happen with a new perspective.

The RIFT house, that cleverly spells out as the Regenerative Ingenuity for Tomorrow, occupies 3,800 square feet at 5,300 feet of elevation. Where temperatures have been reaching new highs for record time spans, the house remains cool and comfortable.

“We lived in Albuquerque and had renovated two dozen homes but had never built a home before and wanted to apply everything we learned,” said Hal Stillman, the home’s owner. “We also have four grandchildren and wanted to share how people can build more intelligently.”

As a retired mechanical engineer from copper manufacturer ABB, Stillman was involved in redesigning heat exchangers, and became well acquainted with energy efficiency, refrigeration, and various aspects of architecture. His wife, Kyrie O’Connor Stillman, helped design the overall layout of the house and sourced all the fixtures and finishing materials to meet LEED requirements.

“If I wanted the best building envelope, I had to limit heat influx in and out, and I could do what I wanted if I had the right systems in place,” he said. “I overbuilt the solar system and minimized the energy use, which created the framework for it. Another aspect was to minimize the amount of materials and the transportation of the materials.”

The solar system ended up being a total of 38 solar panels that would generate an extra 13 megawatts over what the home can put to use, on average 6 or 7 megawatts. Stillman calculated that if he gave that extra back to the grid, he would neutralize the energy that it took to deliver the home to the site.

After a complex spreadsheet and numerous calculations for various framing materials, the couple decided to use structural insulated panels that Stillman could engineer. The calculations showed that the panels would outperform stick built or concrete construction and were also the lowest cost option—by nearly $50,000—during COVID when the cost of wood was very volatile.

The structural insulated panels, or SIPs, also helped minimize materials because the panels are filled with air and graphite expanded polystyrene making the building envelope the minimum weight for the maximum performance. The panel seams are joined by 2” x 6s” and nailed together and all double gasketed. In a blower door test, there was no air infiltration or loss.

While effective, the design again went outside the norm.

“Because it’s tight and well insulated, standard HVAC systems don’t work because the cooling loads are so low,” Stillman said. “We decided on one air source heat pump with ducts that travel to all the rooms with seven zones. They pipe refrigerant around instead of air, almost like a light commercial system. All ducts are exposed for easy maintenance and minimum material use.”

Even in the rift valley where daily temperature swings are extreme, the house maintains a constant 73 degrees. The Stillmans installed sunscreens to reduce the heat load on windows in the morning.

Outside, the property reflects the smart design of the house. A well pump is used for a drip irrigation system that sustains native grass and wildflowers that also sequester carbon around the house. There is a retention pond to capture heavy rain, minimum impermeable surfaces, and any runoff is directed to trees and plants.

Engineering Results

Stillman calculated the payback time for the carbon offset , or the CO2 generated transporting the SIPs to the build site, originally as 13 MWh of electricity, which he forecasted would be produced in about 8 months. The actual came in at a little less than 9 months.

Using a sensor tracking program, he is able to see that the heat pump is 65% of the load, at 7 MWh so far in 2024, the well is 10%, and the pool 8%.

Alongside the big daily temperature swings, the house stands up to violent thunderstorms, airborne dust, occasional earthquakes and wildfires, and cool winters. using only materials that are recycled, repurposed waste, or sustainable. The home is a model for future-oriented sustainable and affordable homes.

The walls have reached a R35+ rating and the roof is R65+, a credit to the insulative value of the SIPs. Plus, heat gain is reduced by the white reflective roof, and 45% of the roof area is shaded by solar panels and a roof deck. An insulated polished concrete floor without floor coverings acts as thermal storage to also helpj maintain the home’s 73 degree temperature.

The Power of Design

The right design obviously can have powerful results.

Peter Pfeiffer, president at Barley|Pfeiffer Architecture, also believes in the power of design and is delivering projects that promote the use of natural resources to be both more operationally effective and more affordable, most notably the Vision House Austin.

Pfeiffer shares that the proper orientation of windows is the biggest influence on a home’s comfort, energy consumption and long-term durability. A home should have windows primarily facing north or south because it is easier to control unwanted solar heat gain in the summer and to collect beneficial solar heat in the winter. Cross ventilation also should be considered when placing windows in the design, which can reduce the need for special outside air mechanical venting systems.

In addition, extended roof overhangs, deep awnings, or covered porches can protect windows facing west from the elements. Plus, the protected windows will last longer and stay cleaner.

Pfeiffer advises designing garages and other unoccupied spaces in a place that can protect the living areas of the home from afternoon sun or winter winds, but not in a way that would block from the benefits of prevailing breezes.

He advises that color has a big impact too. For example, exterior dark colors add to the cost of cooling in the summer and will not hold up as well to the sun’s UV rays, requiring more frequent repainting. Interior dark colored floors and countertops increase the need for artificial lighting, adding to a home’s energy consumption. Plus, interior dark colored floors and countertops add to eye strain and negatively impact health.

“It is absolutely possible for a production builder to have high performance through better design without paying a cent extra,” said Eric Werling, one of the founders of the Zero Energy Ready Home Program during his time at the U.S. Department of Energy and now owner and principal consultant for Home Innovation Strategies. “It just takes an acknowledgement that design is an important element.”

Walsh Construction tried and successfully completed a Passive House certified multifamily project 100% paid for just through the design, Werling said. The builder cut 10% of the floor area out of the plan by eliminating inefficient design features, which paid for what was needed for Passive House certification.

“From my history in the space, it is possible to do incredible efficiency improvements by taking the time to design with multiple factors in mind and get to an optimal design for all the parameters,” he said. “In the residential market it is only done for high end customers who can afford a high end designed house. That’s the only situation that we think it’s realistic from a cost perspective.”

Werling shares a personal example from building a deck on his house for more outside living.

“Right before I started building it and hiring a contractor, I checked with Sam Rashkin who reviewed the design, and within less than a minute he found the inefficiency in the design and it was 20% of space that I didn’t need,” Werling shares. “An architect has been trained to develop a process to look for efficiencies in flow, space use, and I wasn’t thinking in those terms and I was thinking like an engineer. Sam opened my eyes to this reality of thinking about design.”

He suggests taking a step back to acknowledge that it takes a team to create a design optimized for the occupants. It may take extra time, but it will be recouped.

“Removing the wasted space in my patio design was a very memorable incident,” Werling admitted. “In one minute, the architects trained eye saved thousands of dollars.”

That cost savings and efficiency can pay for a design service that can contribute expertise to how the design can influence efficiency and lower maintenance, now and over time.

Future Iterations

Stillman learned a lot from the RIFT project and continues to learn. Better yet, he continues to share what he did and what he learned.

Given the chance, he would have leveraged technology more for visualizations of the interior and exterior and energy model simulations, to evaluate component interfaces, to connect to the builder on the project management, host virtual site visits, and to use remote collaboration tools.

Beyond technology, he would have appreciated a broader selection of green materials and subcontractors who could meet the project’s timelines.

Pfeiffer believes the RIFT project’s design could be improved to manage ongoing costs better, including adding roof overhangs or awnings to protect the exterior walls, and not being so dependent on technologies and the associated expense and homeowner maintenance.