“High-Performance.” For many Americans, it’s a term that summons up visions of gleaming sports cars or lightning-fast supercomputers. But in the last few years, a new and very different kind of “high-performance” item has emerged: a home with turbo-charged comfort, durability, and energy efficiency.
High-performance homes achieve that distinction by any number of improvements, some cutting edge, some mundane. Improving the building’s envelope through additional insulation, installing high-performance windows, or airtight construction can substantially reduce utility bills and improve comfort. Advanced technology like energy monitoring systems give occupants real-time feedback on how they use their electricity. Roof-mounted solar panels can offset the home’s energy needs and even feed power back into the grid. At a time when buildings are the nation’s leading consumer of energy, such features offer concrete means to reduce consumption and accelerate America’s journey towards energy-independence.
A Whole-Building Assessment
But not every improvement delivers the same results, and for homeowners and builders with fixed budgets, the biggest challenge is to strike a balance between energy savings and capital costs. To address that challenge, Fraunhofer CSE’s Building Energy Technology team turned its attention to high-performance houses in the Commonwealth of Massachusetts, setting up a sophisticated monitoring operation to analyze these structures in detail as part of a larger research effort carried out on behalf of the US Department of Energy’s Building America program.
“Compared to the typical residential building in the US, these home are unusual in that they were designed from the ground up to be as efficient as possible,” explains Dr. Peter Engelmann, former head of the monitoring project. “While they’re not necessarily representative of what a home might look like in 10 years, the advantage is that they combine many different efficiency measures under one roof. That allows us to not just see how effective individual measures are, but also see how those measures interact with each other over time.”
Monitoring Homes – And Inhabitants
At each house, a suite of sensors monitored several factors: indoor and outdoor temperature, relative humidity, CO2 levels, sunlight exposure, and electricity consumption at the circuit level. By tracking these factors over the course of a year, CSE researchers could follow the effects of changing seasons and weather patterns. But CSE’s testing went beyond hard numbers — how inhabitants interact with the technology was just as important.
One key finding: if a high-performance technology isn’t working as advertised, chances are that the occupants aren’t aware of it. In one home studied by CSE, the building’s outdoor air supply system wasn’t working, leading to a buildup of carbon dioxide in the house. The drop in outdoor air supply was obvious to the instruments, but the building’s occupants didn’t even notice the problem until the monitoring team revealed it.
Laying the Groundwork
The DOE’s Building America program works with leading researchers, institutions and companies in the buildings space to create substantial, market-ready improvements in residential building energy performance, durability, quality, affordability, and comfort. Gathering and analyzing information like this allows CSE scientists to evaluate energy-saving technologies and make concrete — and more importantly, cost-effective — recommendations to homeowners, builders, and municipalities on how these technologies are best deployed.