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This is part of our special series "Home of the Future." Read more.

Foam panels can turn old abodes into energy-efficient homes of the future

A research team at the National Renewable Energy Laboratory is using machine learning and AR headsets to speed up energy retrofits for residences.
By Alison F. Takemura

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A metal shipping container with a window and door is clad in blocks of beige insulating polystyrene panels.
A shipping container clad in insulating polystyrene panels at the U.S. National Renewable Energy Laboratory (Alison F. Takemura)

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GOLDEN, Colo. — Snow crunches underfoot as I walk around what was once a humble shipping container. Researchers have now turned its facade into that of a tiny house, complete with two windows and a door. The interior? Unfurnished. With this model home, it’s not what’s on the inside that counts, but what’s on the outside: light beige panels of energy-saving insulation.

On a recent January morn, Chioke Harris, senior research engineer at the U.S. National Renewable Energy Laboratory, shows me these prefabricated foam panels, their faces textured like stucco. They’re made by manufacturer Dryvit from expanded polystyrene — a hard foam that doesn’t yield at all under my curious fingers — which can insulate a building like a tea cozy or an ice cooler.

Blocks of textured insulating foam sit on particle board mounted on wood studs attached to a shipping container.
Insulating panels made of expanded polystyrene are mounted and fastened to a faux building facade on top of a shipping container at the NREL campus. For completed retrofits, the gaps between panels would be filled with insulating foam rods and sealed, and siding could be added for a more complete building face-lift. (Alison F. Takemura)

The building sector, including construction and day-to-day energy consumption, accounts for more than a third of annual U.S. greenhouse gas emissions, according to the U.S. Department of Energy. To reduce their carbon pollution, we need to get buildings off gas and electrify them, as well as reduce the amount of energy they use.

Energy retrofits that combine both of these decarbonizing strategies, especially by replacing inefficient fossil-fuel HVAC systems and insulating buildings, can slash the energy required to heat and cool them by 75 percent or more, the DOE estimates.

Energy codes first began to take effect across the U.S. in the early 1980s, according to Harris. Many buildings constructed before that time weren’t built with sufficient insulation, especially in their exterior walls.

It can be relatively easy and inexpensive to add insulation to the exterior walls of buildings with wood frames — one common method blows the insulation material into holes drilled into the wall cavities between the wood studs. But that doesn’t work with masonry buildings made of brick, stone or concrete. Of those, about 20 million pre-1980 units exist, Harris estimates.

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A simple way to insulate these buildings is to attach the insulation to the outside of the exterior walls. It’s also the least disruptive for residents, which makes it all the more appealing to Harris and his team. With the Dryvit panels, the team wants to essentially give buildings foam jackets.

Backed by a $4.8 million award from the U.S. Department of Energy’s Advanced Building Construction initiative, the team is using off-the-shelf products like the panels to develop a streamlined approach that can quickly and cheaply scale residential-building retrofits.

Samuel Petty, technology manager for the project in the DOE’s Building Technologies Office, notes that one of its major strengths is that it utilizes established hardware and software. Instead of generating new technologies, the team is adapting currently existing, commercially available ones, which will allow us to get these efforts to market faster.”

The NREL team will pilot their process on affordable housing to benefit households that energy bills hit hardest.

Adapting a Dutch import

The idea of rapidly insulating large numbers of residential buildings using exterior panels comes from the Netherlands. A public-private initiative called Energiesprong, Dutch for energy leap,” has transformed more than 5,000 homes since it started in 2010. That [program] is the inspiration” for the NREL project, Harris says. (Read more about Energiesprong from climate think tank RMI co-founder Amory Lovins. Canary Media is an independent affiliate of RMI.)

But while swaddling buildings in insulation sounds straightforward, it’s been harder than expected to adapt the Dutch Energiesprong to U.S. housing stock.

In the Netherlands, these projects tend to involve retrofitting a lot of homes that are the exact same shape over and over again,” Harris tells me. A neighborhood of 400 townhouses there, he adds, might come in three very slightly different designs: a mirror image of one, a balcony on another. So it’s pretty easy” to design panels for all of their facades. You don’t need to accommodate a lot of variability.”

That’s not the case in the U.S.: Residential buildings here are more idiosyncratic. We need an [energy retrofit] approach that’s able to accommodate the enormous variety of existing structures, configurations and appearances that exist in the U.S. today,” Harris says.

Streamlining building retrofits

The team collaborating on the NREL project, which includes industrial technology company Trimble and software giant Microsoft, has broken down building retrofits into three major steps, each of which they are honing:

1. Taking the building’s measurements. This step is traditionally done by hand, Harris says. But the NREL team is instead laser-scanning a building using Trimble cameras, taking millions of point measurements that, combined with photos, render the building’s computerized 3D phantasm.

2. Sizing the insulated panels for the facade. Using the building’s measurements, an architect would typically design a configuration of different-sized panels to cover the building and fit its features, including windows, gutter downspouts and doors. Instead, the NREL team is extending Trimble’s machine-learning software to automatically complete this step and choose panel dimensions that most efficiently do the job. (Trimble’s software is normally used to map out interior features of a dwelling, Harris says.)

In short, from the time a person hits a button to initiate the laser scan, all the rest of the process is automated, all the way up until the design documents get delivered to the [panel] manufacturing plant,” Harris says. There’s no waiting on a busy architect who can’t get to the plans for weeks; the adapted software will whip up a design in seconds to minutes.

When installing panels on the tiny container house on the NREL campus, the team pitted their software’s design against an architect’s. The software came out swinging. Because the computer-generated design reduced the variety of different panel sizes and shapes, we ended up with a much simpler layout that was easier to manufacture [and] much easier to install,” Harris says.

3. Installing the insulated panels. The team is streamlining this step in a couple of ways. The Dryvit panels they are using for the exterior insulation are extremely lightweight (2.5 lbs. per square foot) and simple to install. They also come with an embedded aluminum bar that hooks onto a mounted metal rail fastened onto the building exterior. Installing a panel is as fast as hanging a painting.

Man in red insulated jacket touching embedded piece of aluminum in beige insulating panel.
Chioke Harris of NREL shows me how the insulated panels are mounted: An embedded piece of aluminum allows them to hang on mounted rails attached to the shipping container’s faux building facade. (Alison F. Takemura)

Harris says these panels have a real advantage in terms of speed and cost.” Other insulating-panel products can have embedded steel frames that make them much heavier and require forklifts, Harris says. But because these lightweight panels can be hung by one or two people without special equipment, they can be installed in half the time, he estimates.

Short animation of workers installing insulated panels on fiberboard mounted on a shipping container
A timelapse of NREL employees Erin Lewis (gray sweatshirt) and Gregory Shoukas (red sweatshirt) installing rails and insulated panels on the faux building facade of a shipping container (David Goldwasser/NREL)

The team plans to employ augmented reality headsets to make installation even smoother. This will eliminate the need to look between the building and a reference map to determine where the panels go. The headsets project a map of the panels right onto the building itself.

David Goldwasser, a software developer at NREL, gives me a glimpse of this mixed-reality experience, albeit with a tablet, not a headset, which requires some training to use, Harris says.

Using a program from Trimble, Goldwasser loads a 3D model of the container house in front of us. Suddenly on the screen, each blocky panel has its identifier in vibrant orange letters and numbers floating above it. Installing panels this way is like paint-by-numbers — no guesswork required.

Shipping container installed with fiberboard and door has floating orange identifiers, e.g. A10, A5, for square regions.
Screenshot of augmented reality that shows which insulated panels, with their identifiers in floating orange, go where. (David Goldwasser/NREL)

Instead of using a tablet to see this map, workers would wear Microsoft’s mixed-reality headset, the HoloLens, which Trimble has built into a hard hat. So it can be used on a construction site…hands-free,” Goldwasser says.

Retrofitting affordable housing in Colorado

Harris’ team will test-drive their approach in the real world using two affordable multifamily buildings in Arvada, Colorado, about 10 miles from the NREL campus in Golden. The 26-unit buildings have cinderblock walls, making the buildings good candidates for external retrofits. Harris anticipates that by insulating and swapping in heat pumps, they’ll be able to reduce thermal energy use in the buildings to a quarter or less of what it is now.

And it won’t be researchers carrying out the project, but contractors and construction workers, Harris says. The team wants their more-automated approach to be ready for prime time, not just something research-grade.” The goal is to learn enough that NREL’s commercial partners Trimble and Tremco, owner of Dryvit, can substantially scale up” the pace of their deep energy retrofits.

But before that happens, Harris and his team have a lot to do. They’re refining the machine-learning algorithm to identify exterior building features so that it can whip up panel layouts even for complex buildings. They’re sussing out the scope and cost of the Arvada project, including any maintenance work needed to prepare the buildings for the retrofits. And they’ll be collecting a year’s worth of data both before and after the retrofits in order to measure how well the panels perform in hot and cold weather and how much they affect comfort and energy bills for tenants.

With all of that in mind, the target date for the completion of the pilot is 2026. But Harris says that, given the urgency to make buildings more energy-efficient, the team’s improved process for external insulation retrofits could be adopted by industry partners before the final results are in.

That means outfitting more buildings with foam jackets — a makeover that benefits not only building owners and residents, but the climate as well.

Canary Media’s Home of the Future series is supported by Sense.

Consumers need better tools to make their homes more efficient and to foster electrification. Sense technology is built on a simple, proven premise: Customers need real-time information to engage. With the first-of-its-kind Sense app, consumers can see exactly where and how to save energy in their homes. Sense works for utilities, for consumers and for the grid. Leading meter manufacturers are partnering with Sense to create consumer-ready smart meters that take home-energy management to the next level. Learn more.

Alison F. Takemura is staff writer at Canary Media. She reports on home electrification, building decarbonization strategies and the clean energy workforce.