Net Zero Is All About the Building Envelope

ext

The green building expert John Wesley Miller, working with the company Green Builder Media recently completed the latest innovative project in the Vision House Series, namely the Vision House Tucson. This home is located in the Armory Park del Sol neighborhood of Tucson, AZ. The house is fitted will all the latest fixtures and features of a net zero home, yet the basis of its energy efficiency lies in its traditional block and cement construction.

Miller, who has been working in the green building and solar heating field for over 40 years, has designed the walls of the home to act as a thermal-mass storage. This home is also the most energy efficient home he has ever built, while Miller is certain that the secret to an energy efficient home lies in creating the proper building envelope. All the voids in the block are filled, which creates the necessary mass to hold in the cool air during the summer months, and the warmth in the winter. The exterior of the home is wrapped in insulation, which is then coated with three layers of stucco.

blocks

insulation

cement

Miller’s Vision House, located at 413 S. Third Ave. in Tucson, is powered by an array of photovoltaic panels, which will generate 7.2 kilowatts of electricity at peak. In addition to that, the house is also fitted with two rooftop solar water heaters that feed a 150-gallon tank, which preheats outside air in winter and provides hot water. The heating and cooling system was made by Russett Southwest Corp., and the company will continue to monitor its performance.

pv

The home was also fitted with Energy-Star rated appliances, while most of the house was constructed using recycled and sustainable materials. Among others, these include recycled-glass countertops, an electric-vehicle recharging station in the garage, a 520-gallon rainwater catchment, along with lifetime cement shingles and remotely controlled appliances. The home is also designed to use less than half the water of a standard Tucson home.

The Armory Park del Sol neighborhood was planned to become a 99-home neighborhood of solar-powered homes. It opened in 2001, and with three owners having purchased double lots, this latest house represents the 95th home built, so only one lot remains. The price of this latest Vision house is $888,000 for 2,500 square feet of living area and a double garage. While this may seem steep, the yearly utility costs for this home are expected to be no higher that $300. The PV array will also be able to generate more power than the household needs.


Article tags: , , , , , , ,
  • Chuck Newton

    This is the type of example that confuses me. They build an adobe house
    on a passive basis. Except for the decorative wood porch, they achieve
    the building envelope by studs, then particle board, then concrete
    blocks, and insulation, and outise insulation. So, they design the
    walls to act as a thermal-mass, and this takes time, money, and tons of
    work hours building this thermal mass in lawyer after lawyer in
    materials, just so they can cover it all up with stucco. It is so
    aggrevating to watch. The builder could have achieved the same result by
    using EPS panels, cutting tracks in the panels with a hotwire to add
    the electric and plumbing, covering it back up, and spraying the both
    sides of the panels with a concrete scratch coat before adding the
    stucco on the outside and dryway mud on the inside. Same windows and
    decorative wood porch and doors, etc. Less time, far less money,
    little in terms of labor, fewer trades, less materials. This labor
    intensive house is selling for $888,000 for just 2,500 square feet of
    living space.

  • Chuck Newton

    This is the type of example that confuses me. They build an adobe house
    on a passive basis. Except for the decorative wood porch, they achieve
    the building envelope by studs, then particle board, then concrete
    blocks, and insulation, and outise insulation. So, they design the
    walls to act as a thermal-mass, and this takes time, money, and tons of
    work hours building this thermal mass in lawyer after lawyer in
    materials, just so they can cover it all up with stucco. It is so
    aggrevating to watch. The builder could have achieved the same result by
    using EPS panels, cutting tracks in the panels with a hotwire to add
    the electric and plumbing, covering it back up, and spraying the both
    sides of the panels with a concrete scratch coat before adding the
    stucco on the outside and dryway mud on the inside. Same windows and
    decorative wood porch and doors, etc. Less time, far less money,
    little in terms of labor, fewer trades, less materials. This labor
    intensive house is selling for $888,000 for just 2,500 square feet of
    living space.

  • Klimaitė Ema

    I do not agree with the title which says that net-zero is all about envelope. Net-zero is when house consumes the same (or less) amount of energy that is produces by solar panels. So if I cover whole roof of solar panels and produce a lot of energy, my house will be net-zero, but what it means? Exactly, nothing about building envelope. But if I build a house to Passive House standards, then it is about envelope because I care about thermal insulation, sealing every gap, walls, windows, concrete, etc. People, don’t mix net-zero and passive house concepts, if you want your house to consume as less energy as possible, you talk about passive house standard. Net-zero can be achieved by almost every house with many solar panels, passive house standard can be achieved only building in a certain way. Good luck!

  • ergodesk

    Hey Chuck, some people love pain,so why do-it the better way?

  • spr8364

    I’m not too sure how the block acts as thermal mass, if there is a layer of insulation on it from the outside. Seems like heat from the sun, would have trouble getting to the layer of block. The insulation would eliminate any thermal bridging. If the heat gain is coming from the interior through south facing windows, they probably could have gotten the same result with a couple layers of gyp on the inside of a framed wall.

Popular Topics on Jetson Green