As we cross Labor Day weekend off our calendars, we now turn our attention to what the fall season brings. At NATiVE, we see September as the right time to join in the back-to-school spirit and hit the books to learn more about what truly makes a net zero home in Texas.
A full understanding of net-zero housing implies a recognition that the homebuyer is paying for a comprehensive and complete building up-front. This includes the home, and ALL of the energy costs paid for on a monthly basis throughout the life of that house. NATiVE homes on 100% rainwater go beyond the definition of net zero because they also gather water needed for living in the home. While the mortgage will surely be higher, the total monthly costs for owning and maintaining that house will be effectively nil in a world of incessantly rising water and energy costs. It is not difficult to achieve a net-zero house, but it does take disciplined decision-making, a systems-oriented approach, and a greater initial investment in efficient quality materials, equipment, and design.
6 Key Ingredients of a Net Zero Home
The following are six key ingredients of a net zero home. The first five can be loosely grouped as “passive strategies” that promote energy conservation while the last key ingredient can be labeled an “active strategy” implying energy production.
1. Occupant Vigilance / Monitoring systems
The first, and most critical step, is to recognize that a home’s eco-friendliness is ultimately determined by the behavior of the occupant. What good is the best-designed eco-home loaded with cutting-edge technological systems if the occupant forgets to close a window while running the AC, or forgets to turn off the lights when he or she is out?
With that being said, eco-builders such as Native, usually include a user-friendly system of monitoring equipment as standard procedure. Information can be accessed via the internet at any time, allowing for responsive and proactive behaviors on the part of the owner. An eco-friendly home occupied by a vigilant owner can not only operate off the grid, but can also make a profit as it generates more net energy than it produces.
2. Proper Orientation and Responsive Envelope Design
Proper orientation of a building combined with a climate-responsiveness is the most cost-effective way to reduce energy demand. It is quite simply a matter of good design and decision-making that translates to significant energy savings. When designing a net-zero house, this should be the first step, keeping in mind that it is far “greener” and far cheaper to work with nature rather than fight against it.
In Texas, the best form of a house is a long rectangle oriented with its long sides facing north-south. This minimizes direct sunlight, reducing demand for cooling while maximizing sunlight during the winter, reducing demand for heating. When designed correctly, a direct-gain solar home in Texas could get 75 percent of the heat it needs from the sun. It also allows for efficient cross-ventilation and takes advantage of prevailing breezes, which typically come from the south during the summer.
A “building envelope” is effectively the barrier between the exterior and the interior of your home. This includes the walls, windows, doors, and the roof of a building. Thus, it makes absolute sense to avoid penny-pinching in this area. One key aspect of the building envelope is insulation. We cannot stress how important adequate insulation is (one with a high R-value). The higher the R-value, the better your envelope is at keeping out the heat in the summer and retaining it in the winter.
Eco-builders, such as Native, employ spray foam insulation, or alternative wall systems as opposed to traditional batting insulation, for its higher R-value. This allows for the ability to fill in small cracks and crevices, fully sealing the building. Special attention to insulation must also be paid to windows. Look for double or triple paned glass windows which typically have better insulating properties. Also, look for glass coated with a low-e film, and high SHGC (Solar Heat Gain Coefficient) which reflects certain spectrums of infrared light, resulting in less heat gain. It is absolutely imperative that windows and other openings in the building envelope be properly placed and adequately shaded on the outside.
3. Xeriscaping and Rainwater Collection
The lush, grassy front lawn is a ubiquitous fixture of American suburbia. However, they are probably the worst purveyors of water misuse and waste. Depending on conditions, a 25-by-40-foot yard can drink up to 10,000 gallons of water each summer. In some areas of the Western United States, lawns account for 60 percent of urban water use. Keeping America’s grass perfectly cropped requires 38 million lawnmowers, most of which use two-stroke engines that generate as much pollution in an hour as a car does during a hundred-mile trip. Each year, Americans apply more than 70 million pounds of pesticides to their lawns, some of which seeps into groundwater, threatening wildlife and human health.
This could all be mitigated with the use of “xeriscaping” which means using drought resistant landscaping that is adapted to the local climate of various regions. In Texas, why settle for generic and unsustainable Kentucky Bluegrass when a homeowner could have a luxurious prairie meadow of native Buffalo Grass and wildflowers? Xeriscaping combined with rainwater storage and collection systems offered by eco-builders can meet a net-zero home’s water needs.
4. High Efficiency Appliances
After heating and cooling, appliances are the next largest users of energy in the home. It is essential to a net-zero home that energy efficient appliances (water heaters, dryers, refrigerators, etc.) are used. This ensures that the energy being created onsite is functioning at the highest level of energy efficiency.
5. Healthy Indoor Environment
The air inside your home could be more harmful to you and your family than the air outside. That’s because it could be filled with mold spores, pet dander, dust, chemical pollutants, and pollen. In the last several years, a growing body of scientific evidence has indicated that the air within homes and other buildings can be more polluted than the outdoor air. Other research indicates that people spend approximately 90 percent of their time indoors. Native installs a whole house air purification system in each of its homes to ensure the inside air is as clean as possible for your health.
6. Active Technology (Solar)
The most prominent technology employed to achieve net-zero energy creation on site is a solar/photovoltaic installation. While these technologies may be the most glamorous aspect of a net-zero house, they also contribute significantly to the cost difference between net-zero and traditional modes of home construction.
Active technologies such as photovoltaic solar panels provide the sustainable, energy-production punch needed to completely power all of a building’s appliances and mechanical systems. However, as impressive as these technological solutions are, it takes a responsive and well-designed package of both “passive” and “active” strategies to create a functional net-zero home.
Native is your local, eco-building, solar installation, green construction company here to help all Texans passively and actively conserve energy. Build smart. Build Native.