Vahid Mojarrab: [It was] after reading an article on how you can heat your whole house with a hair dryer—I think that was the most brilliant marketing sentence I have ever read. It just hit the core with everybody. I participated in the first Passive House US training in Champaign, Illinois, in the summer of 2008, and I was among the first group of people that got trained in Passive House.
gb&d: What compelled you to get involved?
Mojarrab: It was proven in Europe, and it just seemed to work. It has other benefits for us—it improves the indoor air quality, it forces the building to be built better so that it’s longer lasting. For most of our projects, we try to achieve site-zero energy, and Passive House allows site-zero energy with little effort. It became compelling to present this to clients and tell them that by investing in 1.5- or 2-kilowatt photovoltaic systems they can attain site-zero.
gb&d: Does the climate affect your approach?
Mojarrab: [New Mexico is] in Climate Zone 5, which is a cold and dry climate, and we have the problem of overheating because of high solar gain. We’re doing a project right now where we tried to play with the overhang for a particularly large picture window. Coming up with the perfect overhang is almost impossible. You either don’t get enough solar gain, or you’re overheating. So we chose to go to an active system—in this case, it was an exterior shading device. Then we hit the sweet spot in no time. That’s something that might be different or unique to our region—many of our projects require exterior active shading to achieve the ultimate balance throughout the year.
gb&d: How does your current work illustrate intelligent Passive House design methods?
Mojarrab: When we talk about possible energy-efficiency improvements in the residential sector, we always hear about single-family homes. Multifamily housing has an automatic energy efficiency in some way designed into it. The whole geometry and sharing of walls make energy efficiency inherent with the multifamily. Less saving comes from the envelope or HVAC design, and more of it comes from the water-heating efficiency and appliances. It’s a significant opportunity to bundle energy-saving methods.