By competing in the U.S. Department of Energy Solar Decathlon® 2020 Build Challenge, the University of Colorado Boulder (CU Boulder) team aims to confront the housing attainability crisis and construction challenges facing mountain towns across the nation. The team created the zero-energy ready SPARC House to serve as a replicable example of a high-performance building and an achievable mountain town housing solution. SPARC is built on the five pillars of Sustainability, Performance, Attainability, Resilience, and Community.

Design Philosophy

A triple-bottom-line approach to sustainability was fundamental in the development of the CU Boulder team's design philosophy. The SPARC house aims to address three principles of sustainability: economic prosperity, social equity, and environmental protection. The remaining four pillars that comprise the foundation of SPARC are all rooted in the core concept of sustainability.

High energy performance is critical to reducing the home’s environmental impact, as well as providing low operating costs for homeowners. SPARC incorporates multiple design strategies that improve performance, including a small footprint and highly insulated, airtight structure. The house maximizes natural ventilation and daylighting with orientation-tuned glazing and a low window-to-wall-ratio on the north façade. Additional high-efficiency equipment—such as zone-based ductless minisplit heat pumps, an energy recovery ventilator, a heat pump water heater, maximum power point tracking on the solar panels, and a central control system—help engage occupants in easy operation of the house.

To promote attainability, the SPARC House is designed to leverage prefabrication construction methods that can reduce building costs. An attached rental unit brings in supplemental income for the homeowners while offering more affordable rental options for seasonal workers who support tourism in mountain towns.

The SPARC House embraces the concept of resilience with electrical provisions for future battery storage, grid islanding capabilities, on-site energy generation, demand response capability, and a building automation system that can proactively control the space for daily energy efficiency and to achieve a grid-friendly electric demand profile. With demand response functions, the SPARC House can react to signals from the utility, if a local program exists, and reduce stress on the grid as needed. Additionally, the building envelope is made of durable materials that require minimal maintenance over time and can be repaired with relative ease.

The SPARC House's rental unit provides a multifaceted solution to the displacement of seasonal and year-round service workers in mountain towns. The approach strengthens communities by meeting the needs of those who may not be able to afford typical living costs, but play an integral role in shaping local economies. Long-term rentals also foster interaction and communication within towns, promoting the development of new relationships and unified neighborhoods. With the adoption of the SPARC House, mountain towns will be able to showcase the power of sustainable housing and sustainable communities.

Market Strategy

Mountain communities face multifaceted challenges due to their unique locations. Harsh weather conditions create the need for resilient building systems and materials, and winter tourism causes a drastic seasonal influx of residents needing rental housing. The housing market lacks attainable options for seasonal workers, first-time home buyers, and permanent residents. Without stable housing options for these key demographics, local economies suffer as businesses struggle to hold staff.

The SPARC House addresses the needs of mountain communities in several ways. With a space-efficient, multi-use floor plan, the SPARC House achieves flexibility as the household grows. In addition to renting out the attached unit to seasonal workers, the full-time residents can also use it to transform the house into a cohesive two-bedroom house, or as a solution for a relative aging in place.

With energy modeling and thoughtful design, the SPARC House consumes less energy than standard similar homes and is powered by rooftop solar photovoltaics, avoiding mountain community utility costs, which can be higher than the national average. Additionally, smart systems reduce maintenance and recovery costs, reducing the effective price of the home. The SPARC House is a model of an attainable, resilient, and efficient home that meets the needs of all its residents.


  • Designed for panelized and volumetric prefabrication
  • Includes an attached rental unit
  • Incorporates low embodied carbon materials, such as wood structure, wood cladding, and sheep's wool insulation.


  • Accommodates harsh environment with resilient building systems
  • Provides energy recovery methods
  • Minimizes power mismatch via a building automation system.