labor of love
Susie Marbury translates her commitment to green building into a dream house perfectly in step with the times.
Walls of unplastered autoclaved aerated concrete (AAC) blocks combine high insulating capability with excellent thermal mass, which helps keep the home warm in winter and cool in summer without air conditioning.
The narrow south-side yard includes a pool for regular lap swimming. A garage door eases the transition between indoor and out.
Susie Marbury works at her precious butcher block.
The living room features a tall ceiling, the garage door, and lots of south-facing glass for passive solar heating.
This article first appeared in Winter 2010 Su Casa
I “designed” my first dream house when I was in fourth grade. True to the era, it had a sunken living room, a separate family room, and an interior courtyard complete with an amoeba-shaped swimming pool. Among the more unique features was a fireplace in the center of the family room completely encased in translucent mica walls. I had just learned that mica is resistant to heat, and I thought this would create a cool soft glow. There was also a glass ceiling that could slide across the courtyard to cover the pool area in bad weather. I had no idea how that would function. In fourth grade, I didn’t need to.
Several decades later, I had the opportunity to really design my dream home. Fresh out of architecture school and equipped with enough knowledge to be dangerous, I relished the prospect. My perspective, however, had changed considerably. Over the years I had drawn many more floor plans of various dream houses, each representing my personal desires and outlook and reflecting the predominant American preference for large sprawling layouts and oversize rooms. My tastes leaned toward the casual but still included all the amenities—a large well-equipped kitchen for easy entertaining, a swimming pool and fountains, and an expansive master suite. You get the picture.
Living in a passive solar adobe home changed my point of view. There I first realized that how we build matters. When I got married in the late 1980s, I left that house to join my husband, John, in Placitas, New Mexico. Our Placitas home had lots of character and many wonderful features—being adobe was one—but as our propane bills continued to rise, I became painfully aware that energy efficiency was not one of them. I remembered the benefits of my old passive solar adobe. Constructed in the late 1970s, this was a better way to build, but no one was doing it anymore.
I entered architecture school with the desire to rectify this situation. At the time, I had only the vaguest notion of sustainable concepts, and green was nothing more than my favorite color. I had been a computer professional for many years—everything from programmer to sales support to systems manager—but I began to seek something more meaningful. Recognizing the effect our homes have on our quality of life, I embarked on my midlife career change.
I enrolled in the University of New Mexico School of Architecture and Planning, where I completed my master of architecture degree in 2002. In 2000 I was fortunate to be doing an internship with the City of Albuquerque as it was creating an organization called the Green Alliance. I was hired as the executive director. In 2003 the Green Alliance transitioned into what is now the New Mexico chapter of the U.S. Green Building Council, an organization that continues to educate and promote green building. I now work for the New Mexico State Energy Office promoting energy-efficient green building and administering the Sustainable Building Tax Credit. As the current chair of the U.S. Green Building Council’s New Mexico chapter, I get to do what I love vocationally and avocationally.
bringing green design home
In 2004 my husband and I sold our house in Placitas, found a lot near Old Town Albuquerque, and committed ourselves to building our new green home. Goal number one was to keep it small—around 1,500 square feet seemed right. Passive solar and energy efficiency went without saying. At the time I was working as a LEED consultant for a local architecture firm. Although my work primarily dealt with commercial buildings, the concepts still apply. It has to do with a comprehensive approach that looks at all aspects of how a building impacts the environment: site, water, energy, materials, and indoor environmental quality. I was soon to understand that the challenge lies in the application of the concepts.
Our site choice was based on my desire to be close to amenities (shops, restaurants, and other conveniences) and public transportation. Albuquerque has few optimum areas in this regard, especially if you are looking for vacant land. The lot we found near Old Town met many of our requirements. The lot is small—about a sixth of an acre, flat and easy to develop, and within walking distance of museums, drug stores, the 66 bus, and more. That decision was easy, and we’re still pleased with our location.
Our house is constructed primarily of autoclaved aerated concrete (AAC) blocks left exposed on most of the exterior and some of the interior. With its sharp, clean lines, AAC dictated a modern home style, as opposed to the softer look of adobe. The combination pitched metal and flat parapeted roof, however, reflects our Southwestern heritage. Our final 1,955-square-foot floor plan contains a generous kitchen and great room, two baths, and a utility/pantry. We have three bedrooms—one we use as an office and another doubles as a psychotherapy office for my husband and occasionally as a guest room. My design intent focused on functionality and efficient space utilization, minimizing hallways and creating an easy flow.
When I designed our home, the Build Green New Mexico and LEED for Homes rating systems had not yet been developed. Drawing from resources available at the time and our own personal desires, I incorporated as many green features as I could determine how to do—and could afford. With energy efficiency the key priority, I started with a passive solar design and a tight building envelope. We left the radiantly heated concrete floors exposed for thermal mass and oriented the majority of windows to the south, including a fully glazed garage door in our great room. To achieve a tight building envelope, we used foam insulation under the roof deck and in the two frame walls as well as low-E, double-pane aluminum-clad wood windows. We also incorporated energy-efficient lighting and appliances, water-conserving fixtures, and nontoxic materials.
While sitting in our living room, my husband smiles at me when I exclaim, seemingly out of nowhere, “I love this house.” The high-pitched ceiling in the great room gives the home a spacious feel beyond its actual size. The thermal mass of the AAC provides warmth and a sense of comfortable solidity. In the summer, the AAC keeps our home amazingly cool, even without air conditioning. We take advantage of the comfortable evenings and enjoy an indoor/outdoor feel by opening our “garage” door. I love to cook, and my kitchen works, with a handy spice drawer under the stove, my precious butcher block, and our convenient recycling center, which consists of pull-out cabinets with bins for sorting glass, metal, paper, and plastic. I truly hate doing housework, but I do appreciate my central vacuum system and my hideaway ironing board. And all summer long, my husband and I spend time in our small rectangular lap pool daily.
lessons in hindsight
Looking back, I see that my excitement and eagerness to move out of the tiny rental in which we were camping out and into our dream home caused me to shortchange some necessary research. I had investigated all kinds of new products: a residential version of infrared bathroom faucets, waterless urinals, insulation options, and Energy Star appliances and lighting. I attempted to understand the complexities of whole-systems design—how the interaction among the building orientation, structure, and mechanical systems can reduce energy use and improve comfort. Still, I did not do enough. In part, I thought I could rely on the expertise of the trades. Unfortunately, I didn’t understand that because this was uncharted territory, I needed to supply the expertise.
I wanted to be my own owner/contractor to really learn the process. My lack of detailed knowledge about construction and the new approaches required to build green, however, resulted in missed opportunities. One example is my desire to incorporate a gray water system. I thought my plumber would know how to do it. By the time I understood he had no experience in this realm, it was too late to make it happen. Today growing numbers of tradespeople have green-building expertise, and we need to continue providing extensive training to our professionals so we can incorporate new building practices and realize the green potential.
In my work promoting green building, I’m often asked what structural system I would recommend for people’s homes. The choices are numerous, from traditional adobe and strawbale to engineered insulated concrete forms (ICFs) and structural insulated panels (SIPs) to advanced wood framing systems. It’s important to understand that there is no “perfect” green material. All have pros and cons. Your choice is dictated by aesthetic preferences, budget constraints, availability, the persuasiveness of vendors, and simple personal predilections.
In our case, I had become enamored with AAC while doing a studio project in architecture school. Builders in Japan and Europe use AAC extensively, and I knew that some use it in the southeastern United States, too. Not thinking it very green to ship material from across the country, I was delighted to find an AAC manufacturer in Arizona. AAC basically consists of concrete blocks that have been baked, or autoclaved, so they are infused with air bubbles. The resulting material has insulating value because of the air bubbles and thermal mass properties because of the concrete. AAC enhances the effectiveness of my passive solar design. In addition to the thermal properties, AAC is fire and mold resistant and provides great sound insulation. I also like the way it looks. We decided to leave the AAC exposed on the exterior and parts of the interior, which also reduced materials and cost.
This was another area where my lack of construction experience caused difficulties. Although I still think AAC is a great product with many advantages, I wasn’t aware that finding experienced labor and providing appropriate supervision was going to be a problem. One of AAC’s key advantages is that it essentially eliminates heat loss through cold spots or thermal bridging found in typical wood framing. Similar to the gray water system, using a new product meant that the labor force was unfamiliar with the nuances of how the blocks should be laid, and as a result, many blocks had insufficient mortar or sometimes no mortar between them. Instead of cold spots created by wood, we had clear openings, inside to out. My husband and I used a flashlight at night to find the empty spaces and plug the holes. Stuccoing the exterior may solve the problem, but as our intent (and budget constraints) dictated leaving the AAC exposed, we chose to plug the holes. Had I better understood the construction industry, I would have realized the training and supervision required to successfully introduce a new building technology.
building on past experience
Overall, I loved the process of building our home, and the result. I encountered some disappointments, but I also experienced many satisfying moments that still linger. Most of the subcontractors were very professional and understood and embraced our goal of building green. They willingly worked with me to address the myriad problems that arose during construction and helped come up with inventive solutions.
Building a green home requires balancing personal values and preferences with environmental concerns and financial constraints. Today we have the LEED for Homes and Build Green New Mexico rating systems to assist in guiding the design and construction process and evaluating the results. Energy Star guidelines help assure that homes are properly insulated and sealed and that wise lighting and appliance choices are made. We are also very fortunate in New Mexico to have a generous tax credit to help offset the costs and reward the efforts of green building.
Through the years my personal outlook shaped each dream house I imagined for myself, leading up to my current home. And now, after decades of seeing houses grow in size and include widgets and gadgets for every purpose, prevailing trends appear to be shifting. High utility bills and awareness of global warming, among other factors, have prompted us to reassess our excesses.
Building a home involves many hard choices and difficult decisions. What do we really need, and what do we just think we need? What improves our quality of life, and what complicates our lives? These are today’s questions. Making a home green may add to the complexity of the design and construction process, but it should yield a simpler and higher quality solution. My expectation is that with each iteration, individually and collectively, we learn from what went right and wrong and continue to realize improved results.
green features at a glance
Site: One-sixth acre near Old Town Albuquerque
Water: Minimal landscaping with fruit trees but no grass, low-flow fixtures including dual-flush toilets and a waterless urinal, as well as a low-water-use dishwasher and clothes washer
Energy: Tight thermal envelope, in-slab hydronic heating with solar assist, passive solar design, no air conditioning, fluorescent and compact fluorescent lighting for more than 50 percent of fixtures, Energy Star appliances and ceiling fans, foam insulation under the roof deck and in the south frame wall, and reflective metal roofing and white thermoplastic polyolefin (TPO) roofing
Materials: Some recycled content, recycling center, AAC blocks (composed of approximately 50 percent air), exposed concrete slab floor, and natural clay plaster
Indoor air quality: No-VOC paints, nontoxic and mold-resistant AAC blocks, natural clay plaster wall covering, and tubular skylights to increase daylighting
what I like about my green home
Autoclaved aerated concrete (AAC) This building material provides a wonderfully solid, quiet building envelope with thermal mass. I’m still surprised how comfortable we are in the summer without air conditioning.
Water conservation Although we have neither a large yard nor any grass, we do have a lap pool. An automatic pool cover prevents evaporation and eliminates a pool heater. Indoor water-saving measures, including a waterless urinal, have also proven effective.
Floor plan and design Though I exceeded my 1,500-square-foot goal to fit a home office, shared guest/client space, and kitchen large enough to contain my butcher block, the house flows well, with no wasted space.
what I would do differently
Assemble a knowledgeable team In the beginning, I would gather a team to review the design and discuss ways to better achieve our goals within our budget. This would include a HERS rater, green contractor, and mechanical subcontractor, for a start.
Hire a contractor Instead of contracting the home myself, I would work very closely with a contractor. It takes extensive knowledge and collaboration when pioneering new ideas.
Conduct additional research I would do more of my own research and better utilize professional expertise.
Redesign the plumbing system I would include gray water and take better advantage of our on-demand water heaters—placing the home’s piping in line with points of use would have greatly improved efficiency.
factors still to be determined
Mechanical ventilation Tighter homes minimize air infiltration. Energy Star recommends mechanical ventilation if a house has less than .35 natural air changes per hour (NACH). At .22 NACH, our house is tighter than that. We do quite well opening windows, but this isn’t the ideal solution during windy or cold weather. I’m not convinced mechanical systems are the only answer, however. More research . . .
Frame wall To contain costs, I changed an internal wall from thermal mass to frame. I believe this compromised the passive solar design, but I don’t know to what degree.
Solar hot water system We installed a system to help with our radiant heating. So far we haven’t achieved the savings we had hoped for due to a defect in the collectors. Since the collectors have been modified, we’re hoping to see more benefits this winter.
Susie Marbury, a LEED accredited professional, is the energy efficiency and green building administrator for the New Mexico Energy, Minerals, and Natural Resources Department. She earned her master of architecture degree in 2002 and currently serves as the chair for the U.S. Green Building Council New Mexico chapter, of which she is a founding member.