Modeling an Efficient Home: Energy Modeling as a Design Tool
63rd St. Ranch Residence, a Net Zero Home
While many of our clients are interested in ‘sustainable’ architecture, few have a clear vision of what that means, and how it will impact the design and construction of their home.
This is, at least partially, because ‘sustainable’ is a broad concept, with varied parameters and approaches. It might include sourcing local products, incorporating photovoltaic energy, selecting ‘green’ materials, reclaiming construction waste, the list goes on.
Our challenge is to determine which efforts will yield the greatest results without compromising the aesthetic, functional, or budgetary goals of our clients. Our solution? We focus on energy efficiency and rely on sophisticated modeling software to compare and contrast the options.
63rd St. Ranch Residence
How does it work?
Energy modeling is a way of predicting the energy efficiency of a home while in the design phase. It allows us to plug in different products and solutions, adjust the size and orientation of features, test mechanical systems and insulation packages and, ultimately, hone in on a design that meets or exceeds our efficiency goals.
63rd St. Ranch Residence
What can it tell us?
The software uses a metric called ERI or energy rating index that weighs the energy-producing and energy-using components of a home to generate a numerical score between 0 and 100.
A ‘net zero’ home has an ERI of 0 which means, in theory, that the home produces as much energy as it consumes.
An ERI score of 100 is not a max waste, grossly inefficient home but rather equates to the energy efficiency of a national code average home. I.e., It’s a moving target so, as an industry, we can constantly improve.
Most of the homes that we design fall between 0 and 30 on this scale (meaning that our projects are at least 70% more energy efficient homes built to national building codes). That said, the demand for net-zero homes is on the rise, especially in Boulder County, and we are happy to oblige.
How do we use it?
Unlike most architecture firms, we do all of our energy modeling in house rather than hire an outside consultant. The reasons for this are twofold:
We know the project infinitely more than a consultant and can make clear decisions based on the preferences of our clients.
This makes the feedback loop more productive and allows us to seamlessly integrate efficiency and design goals.
We don’t just use energy modeling as a reporting tool to make sure that our project meets Boulder energy codes. Instead, we use it as a design tool throughout the process—an ongoing cost-benefit analysis that guides our every move.
63rd St. Ranch Residence
What are the results?
There are many, MANY ways to achieve an energy-efficient home. It comes down to selecting the right combination of components: mechanical systems, thermal envelope, energy usage and energy generation.
For example, many of our clients want large windows and are seeking a strong indoor-outdoor connection with open views of the surrounding landscape. But, even the most advanced window systems work against the energy efficiency of a home, so we have to uncover solutions that deliver the experience our clients are seeking while mitigating the loss of energy.
This might mean adding photovoltaic panels (great for the Colorado sunshine), adjusting the size and placement of openings, opting for more expensive but more efficient window systems, or a myriad of other options. We can choose the most cost-effective route or utilize the path that most resonates with our client.
63rd St. Ranch Residence
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In any home design, there are several combinations of materials and components that can achieve the same ERI score.
At bldg.collective, we strive to create homes that are aesthetically attractive and architecturally interesting, but also comfortable, with systems that work efficiently and in concert with one another. The most energy-efficient homes use several strategies to achieve their goals, and we can model, test, and build all of them.
