We’re pleased to announce John Neville and Jawn McKinley as the winners of our first Low Impact Living Green Home Contest! Of the over 1,000 users who registered using our Environmental Impact Calculator during the contest period, their Low Impact Living Index of 11 was the lowest of the low. Given John’s background, it’s no surpise – he has been working in sustainability for over 20 years and is on the Board of Directors ofSustainable Arizona – as you’ll see, he practices what he preaches!
John and his wife Jawn had begun to employ many green techniques in their former home in Minnesota, but when they decided to build a new home in Arizona he started with a clean green slate. The results were pretty impressive: their Low Impact Living Index is a mere 11, which indicates it has an environmental impact nearly 90% lower than the typical home in his region. Compared to the average home in the desert southwest, the house uses 85% less energy and 90% less fresh water, and it produces 90% less stormwater runoff, 80% less trash and over 99% less wastewater! Oh, and John and Jawn’s carbon footprint is a net zero due to the high energy efficiency of their home (including a solar hot water heater and passive solar heating and cooling), the purchase of green power from their utility, and their use of carbon offsets for their cars and air travel. We’ll now walk you through the main areas that allowed John and Jawn to achieve this amazing performance.
Energy Efficiency & Carbon Footprint
John and Jawn’s LILI score of 11 is nearly 90 points lower than the typical score in their region, and 45 of the 90 point reduction come from their efforts in energy efficiency (and associated carbon footprint). They’ve done all of the easy things – compact fluorescent lighting throughout, low-flow water fixtures, pipe insulation, efficient appliances, etc. But they’ve also employed some more substantial and advanced green building features, including:
- Use of a solar hot water heater and in-floor radiant heating to heat the house in the winter. The house is also oriented to the south, has a heavy concrete slab to retain heat and ample windows on the south wall to improve passive solar heating.
- Despite summer daytime temperatures in the high 90s or more,the house has no air conditioning. The roof is insulated to R-45 and has a cool roof installed, and the walls are formed by insulated concrete forms (ICFs) that are insulate to R-25 and are made of 85% recycled material. In addition, John can circulate cool water through the radiant system to further cool the slab on hot days. There are also awnings over all south-facing windows that shade the intense summer sun (shown at right on a sunny summer day).
One side benefit of these features: John says visitors are often amazed that he’s always walking around in bare feet, whether it’s on an eight-degree winter night or a 100-degree summer day!
Because their home is so efficient right now, solar electric doesn’t make all that much sense yet: the payback period would be more than 20 years based on current power prices and rebates. Instead, he buys green power that comes from solar and wind energy from his local utility.
Water and Wastewater Efficiency
Another 32 points were lopped off of their LILI score by being incredibly water-efficient. This is critical in the Southwest, as water is always scarce and getting scarcer due to global warming. Once again, John combined the accessible with the truly innovative to build a water efficient house. Through a combination of low-flow fixtures and water-efficient appliances, John and Jawn use only 30 gallons a day per person indoors, much lower than the national average of 70 gallons per capita per day.
In Arizona, though, it’s what outside that really counts, for over half of residential water use is for irrigation. John and Jawn rarely use any irrigation water, for not only do they have all drought-tolerant native plants around their home, they also have 3,500 gallons of storage in two cisterns (almost three months worth of irrigation) to collect rainwater from their rooftop. And, they have an innovative wastewater system that collects solids in a tank, aerates and lightly chlorinates the liquids, and then distributes the cleaned effluent to water a bed of native plants and trees – they have nearly zero true wastewater discharge.
The balance of John’s LILI savings come from nearly eliminating stormwater runoff (four points) using cisterns and an innovative network of terraced gardens, swales and water holes to slow, filter and capture runoff from all but the biggest storms (all shown in the image above). They also compost and recycle everything they can, reducing trash to only 20% of the typical household in his region (eight points).
While John built their home from scratch, he learned lessons that are applicable to both new construction and renovation projects. Some of his key thoughts:
- Always start with the small projects first. By focusing on such things as using compact fluorescent lighting everywhere, making sure his home was very tight and well-insulated, and using low-flow water fixtures, he was able to get away with much smaller heating, cooling and renewable energy systems. This in turn helped him keep his overall budget quite reasonable – about $185 / square foot.
- Use the local climate to your advantage. John designed his home so that it takes advantage of Arizona’s ample sun in the winter and the cool of the earth in the summer, but you can often do the same with an existing home. John recommended that a neighbor run only the ventilation portion of her central AC system at night to bring the cool desert air into her home, and that simple change reduced her AC needs by several hours each day.
- Green doesn’t have to be more expensive, but it might require more time and effort. When John built his home five years ago, he said that many of the vendors he worked with weren’t familiar with green techniques and products, and he had to play a very strong oversight role to make sure things got done the right way. There are many more green product and contractor options now, especially near larger urban areas, but you’ll still have to spend some significant time ensuring that your contractors are using the right green products and techniques.
One final key lesson that John has taken away from his green efforts: regardless of how much you’ve done, you can always improve. He says he’s always tweaking things and making minor improvements. As for big projects, John hopes to get rid of his backup natural-gas-powered boiler (used only in the coldest and grayest of winter periods) and replace it with a solar-PV-driven tankless hot water system at some point, eliminating his last use of fossil fuels at home.