Case Study: Casa Mirasol

Casa Mirasol is a Spanish style, green home recently completed in Napa Valley, California. The home hosts an open floor plan kitchen, dining and living room, two spacious bedrooms with sliding barn door closets, and a hidden home office. Casa Mirasol is a true Passive House, meaning it is a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and internal gains from people, electrical equipment, etc. As a true Passive House, Casa Mirasol is a near zero energy building and carbon neutral.

The architect, Jarrod Denton, is the co-founder of Signum Architecture, LLP in Saint Helena, CA, a full-service architectural firm, focused on winery, residential and custom commercial projects. The builder, Rick Milburn is the owner of PassivWorks, Inc. in Vineburg, CA, a family of quality-oriented craftspeople dedicated to sustainable construction and renovation.

The architect, the builder and the owner spoke to us about Casa Mirasol and its features, including the extensive use of Zola products.

What was inspiring or different about this project?

​Jarrod Denton, architect: “Every project that strives for the passive house standard is rewarding and challenging. There was a significant hurdle at the very onset. The challenge was to find a perc test for a septic system and we were down to the last square foot of land for the primary and backup system. Additionally, water was a challenge in this particular area. The owner ended up installing rainwater storage tanks for landscaping through the summer months.”

What were some of the other design challenges for this project?

Jarrod Denton, architect: “One of the first design challenges was to site a primary residence behind the existing guest house which was located on the street frontage. A number of studies were made to understand the sloping site, views, approach to the entry door, and parking. The result was to align the entry doors with the rear of the guest house and create an entry courtyard with fountain to showcase the owner’s landscape talents.”

The owner: “We wanted to build an energy efficient home with a smaller carbon footprint. Our acre lot was long and narrow and space was a major consideration. There was also the challenge of tying in the layout of the new house with the existing cottage that we built several years before. Our architect, Jarrod Denton was invaluable in solving this layout.”

Did using Zola Windows and Doors help accomplish any of these?

Jarrod Denton, architect: “The project was on a defined budget and Zola provided the best all-around value to achieve the performance, air tightness, and clad exterior the owner desired.”

Rick Milburn, builder: “Zola provides an excellent product and support for the Passive House Community.  The best part, they make a daunting process simple.  Love the support after installation, this is a sign of a sure winner.”

What makes this project outstanding?

Jarrod Denton, architect: “The rear loggia that links all rooms of the house together and captures the westerly views of the vineyards and eucalyptus trees at the rear of the property. The beautiful entry door with the rectangular transom above that open up to the library rear loggia connecting the entry courtyard to the rear half of the property. The project brought together for a third time the talented passive house team, including Rick Milburn of Passivworks Inc., along with all of the experienced subs and incorporated all of our collective design and build experience. With every passive house that we build together, we continue to build upon our past experiences and bring a real value to the homeowner. The home is simple in layout and choice of materials but honest and durable, providing a home that could be passed down from generation to generation. The level of comfort in a passive house- from the indoor air quality to the absolute quietness one experiences from not hearing mechanical systems operate or drafts within the home is hard to convey.”

“PassivWorks brings a wealth of knowledge to a project. Rick Milburn is passionate about his work and the quality of the product delivered. Extensive time and effort have been invested into learning ways to build better and projects are a true collaborative effort. It is a pleasure to have a builder, subs, and architect always striving to deliver the best product possible for a given budget.”

The owner: “The house was extremely well built and energy efficient while maintaining the style we wanted.”

“We’ve built a number of houses over the years and worked with some pretty terrific people. Rick and his PassivWorks team take building to another level. The workmanship is outstanding. He provides terrific advice and guidance on thinking through the thousands of decisions, large and small, that you go through. He communicated well, was personally involved every day, never surprised us, and kept meticulous care of the schedule and budget. Usually we’re educating people on green building but Rick’s enthusiasm and knowledge of green building is among the top in the country. Rick proves that you don’t have to give up comfort or style to build a net-zero energy house.”

“A few months after we moved in, we experienced a 6.0 earthquake with the epicenter 5 miles from our house. The house was so well built, we had no damage, faring better than most of our neighbors. Rick was knocking on our door the next day at 8am to check on us. He was making the rounds with all of his clients to make sure they were OK. We have a new friend for life.”

What was your personal focus for this project?

Jarrod Denton, architect: “To match the simplicity the owner achieved with the front guest house while elevating the concept of what a ‘home’ should feel like. Trying to achieve not only the typical goals which might be aesthetics, space layout, functionality, indoor/outdoor living, natural light, proper orientation, and energy efficiency but to also look at indoor air quality, durability, life cycle cost analysis, to create a sense of peace or relaxation by minimizing sound within the house.”

What are some of your favorite construction products used on this project?

Jarrod Denton, architect: “Zehnder America Energy Recovery Ventilators, Laminated Veneer Lumber, and Zola Windows and Doors.”

The owner: “We used Zola’s Tilt-Turn windows and doors. While being beautiful, they are exceptionally well built, easy to clean and insulating. The French doors along the loggia (all rooms in the back of the house) let in natural light while showing off back property views.”

What is your favorite Zola product?

Jarrod Denton, architect: “The PanoramicView™ product. I am still seeking to specify this on an upcoming job.”

What do you like about Tilt-Turn windows?

Jarrod Denton, architect: “I have used tilt turn windows for almost 20 years and I enjoy the air flow that you get through a home by the tilt feature. This provides a wonderful convection air stream and most owners are amazed at the tilt swing option of the doors.”

The owner: “The way the door/window handles open, close and tilt will take some getting used to for Americans, but overall the style and benefits are worth it.”

Was it hard to sell your client on them?

Jarrod Denton, architect: “No, not at all. The client had lived in Germany for awhile and was familiar with the feature.”

Why do you think more Americans might consider using them?

Jarrod Denton, architect: “They provide a wonderful value allowing the owner to have two windows for the price of one. There are many circumstances where you want the window or door to perform differently and having options to both tilt and turn is a luxury that, once you experience it, you benefit from over the entire lifespan of the house.”

How would you describe the House Design?

Jarrod Denton, architect: “A very warm and inviting house with clean simple lines. A house that appears from the onset as possibly understated but reveals nuances at every turn. Some Southwest influences were brought into the fold with the owner’s loving touch.”

What is the view you see from the windows or doors from the house?

Jarrod Denton, architect: “The primary views are in an east-west direction. To the east or front of the house the courtyard and guesthouse are predominately seen. The west or rear of the house is built on an approximate five percent slope with large expansive views to the vineyards and eucalyptus trees at the edge of the property.”

The owner: “It’s all about the views from the windows and doors into the courtyard and to the back of the property. The windows and doors that surround the house give us the openness of that indoor-outdoor feel. The courtyard was designed with multiple garden rooms and entertainment purposes. It is also the main entry into the home. The loggia along the back of the home has a completely different feel. There are open rural views of vineyards, barns, horses, etc.”

Signum Architecture believes that its architecture must be sustainable by design, with each project reaching the highest level possible given client needs and interests. Signum designed the first and second wineries in California to be certified LEED Gold by the U.S. Green Building Council. Signum Architects are Registered Architects in California, Washington, Hawaii, and Mexico. Jarrod is AIA, LEED AP BD+C, and a Certified Passive House Consultant and is a pioneering expert in use of the German Passive House technology in the United States. His passion is about bringing fresh design ideas and appropriate, innovative technological solutions to architectural challenges, regardless of size, purpose or budget.

PassivWorks, Inc. is a family of quality-oriented craftspeople located in the wine country of Northern California dedicated to sustainable construction and renovation.  They combine green building practices with hands on excellence, commitment to design, and integrity with every project from a kitchen remodel to the ultimate eco-devine Passive House. PassivWorks, Inc. specializes in quality craftsmanship, with expertise in building high performance homes. Their skilled tradesmen work together virtuously and efficiently to ultimately realize your dream.  

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