Two Homes in One: Casita and Model Home
This project, a medium-sized home or guest house, is designed for two sites. One is on The University of Arizona campus. This location gives a unique learning opportunity to design-build students in the College of Architecture. The goal of this project is to provide high performance building knowledge to students soon to join the work force and inform others about the possibilities of carbon-positive architecture.
We also designed the project so that it could be replicated across Tucson. We have designed this home to fit in most Tucson backyards. The floor plan is modular, with living, sleeping, and utility zones that can be rearranged to fit a variety of lot sizes. The project shows the potential of additional dwelling units (ADUs), which are often referred to as casitas in Tucson, to add to the tax base while reducing demand for limited energy resources.
The house offers three different high-performance wall assemblies to increase affordability in our market. We also feature a ramada used to generate PV electricity and provide refrigerant-free radiant cooling that pays homage to a local architectural precedent.
One point of inspiration behind the Barrio 2.0 came from Tucson architect Judith Chafee. Her Ramada House includes a superstructure that shades the main house from the harsh desert sun. Chafee's ramada was the inspiration for the dual-purpose solar and radiative cooling ramada on our structure.
The shading structure ramada not only helps protect the building from the sun, but also produce energy for the building, while the butterfly shape allows for rainwater to collect on the panels. This shape was chosen to help rainwater collections and the night sky cooling. The angle that was chosen for its best energy production and allows for the highest potential of water collection.
Tucson’s clear skies provide opportunity for the project to release heat into the night sky, we can pump water onto the roof in the evenings where it will cool before being stored in insulated thermal storage tanks for cooling demand during the day.
The floor plan provides a generous shared living area, two bedrooms, and an ADA-accessible bathroom.
Modular Utility Unit
All necessary mechanical systems, including a conditioning ERV, an air-to-water heat pump, a heat pump water heater, along with a washing machine and dryer and an optional grid-tied battery, are located in a modular mechanical room. This design, which is shared with Casa Donante, could be fabricated off-site to reduce construction costs. It could also be used to provide new systems to lightly retrofitted existing houses in the SunBlock.
From Design Build to Job Potential
Within the College of Architecture an option studio ,Design Build, is offered to fourth and fifth year architecture students. The class provides students the opportunity to gain real on-site building experience. This is a great opportunity for teaching high performance building strategies.
The ADU design could support a job training program, inspired by the design-build class. People in the community could learn valuable high-performance construction methods while gaining hands-on experience.