Despite the obvious benefit of lower energy costs, many buyers question if the upfront investment in green homes is worth the savings. Nathan Day, the developer of Arizona’s first NGBS-certified community, decided to use his own home as a model to evaluate the National Green Building Council Standard cost vs. benefit ratio.
Day’s project, Sterling at Silverleaf in Scottsdale Ariz., is the first single-family home in the state of Arizona to achieve gold-level certification from the National Green Building Council. Designed by architect Bing Hu, the 16 villa community is located in the Sonoran Desert. The community built in partnership with Sterling Collection Development Group and Luster Custom Homes consists of three or four-bedroom homes that average 3,000sqf and cost from $1.36 million.
To test the Sterling home’s energy performance against a similar non-NGBS home in the same climate zone, Day acquired help from a certified home energy rating team. The team included aspects such as heating, cooling, hot water, lighting, appliances, and photovoltaics. The results were impressive, the certified home saved 74% or $265 in energy costs per month compared to the traditional home.
Nathan Day was interviewed about the findings and this is what he had to say.
Did You Learn Anything New About How Best To Build High-Performance Homes?
Day said that “It all comes down to the details and how each system you implement assists the others in efficiency”. For example days suggests that it makes sense to use spray-foam technology for your insulation if you install top-of-the-line windows, likewise if you install the most efficient HVAC system it doesn’t make sense to use incandescent light bulbs that produce considerable amounts of heat and energy loss.
How Much More Does A High-Performance Home Typically Cost?
Day indicates that “on average, a high-performance home will run 9 percent to 12 percent more. However, the longevity of the home is considerably longer than that of a traditional home”. Day continues, “Our buyers will not need to change a light bulb in the first 15 years they own their homes. Our air filtration is eight times more effective than a HEPA filter. Quality of life is better in energy-efficient homes, and that’s what we market to our buyers”.
Are Luxury-Home Buyers Wooed By Energy-Saving Features?
Day points out, “a luxury buyer might not be as concerned with the overall cost of the electricity but an overwhelming majority of them are concerned with the environment. And they feel that the pride of owning the most efficient luxury home in Arizona sets them in a class of their own”.
What Are The Top Energy-Saving Features You Put In Your Green Buildings?
- Day asserts, spray-foam insulation is the No. 1 element that contributes to a green home thanks to the seamless air barrier. He says that traditional fiberglass insulation allows air to pass through the wall studs and insulation batts spaces. Day punts open-cell spray polyurethane foam insulation because it doesn’t have seams or cracks and immediately expands to fill every nook and cranny. In addition, it never needs to be replaced because it doesn’t settle or sag over time. Day says, “We use Gaco Wallfoam, which reduces our buyers’ monthly energy bill by up to 40 percent, creates a comfortable, draft-free home, and controls exterior and interior noise levels”.
- LED lighting and dimming app is the second most important green feature. Day states that “In addition to specing LED bulbs, we offer a proprietary iPad app, developed by Crestron, that dims the home’s lighting to 85 percent power, an easy way to lower energy costs and extend bulb life”. According to Day, studies have shown that the human eye cannot differentiate between lighting at 100 percent and 85 percent, which means residents are not inconvenienced but can save up to 15 percent on their lighting bills.
- Hybrid water heaters are next on Day’s list. He says, “We like the Eternal hybrid water heater, which is 98 percent efficient, durable, and leaves almost no carbon footprint”. Day indicates that 80% of energy consumed by a traditional heater is used to reheat the stored water. So besides large energy savings, tankless heaters take up less space and last 5 to 10 years longer than a traditional water heater.
- The final item on Day’s list is dual-pane, low-E windows. Day observes, “In the average single-family home, 20 percent of all heat loss occurs through windows. Single-pane windows are especially problematic as they let out 20 times more heat than nearby walls”. Day concludes that depending on the age and construction, a typical home could save up to 21 percent on annual heating by replacing regular windows with dual-pane, low-E windows.