What is a True Net-Zero Energy Home?
The term Net-Zero is used so frequently to describe any energy-efficient home today, that the term is becoming watered down to simply mean “green whatever.” The term Net-Zero Energy, has a precise meaning, which basically is, the home produces as much energy as it consumes over a 12 month period. In order to determine the correct consumption of energy, there is a scientific process to calculate the energy need. Since energy usage fluctuates according to the season, some months you’ll find usage to be higher and other months it will be lower. So the homeowner with a Net-Zero energy consumption is simply spreading out the cost over the course of a year. But at the end of that time period the cost is zero. It is not necessary to be certified in order to be Net-Zero, but it is necessary to do the calculations!
Meeting with News-Press reporter Andrea Stetson and Alex Harvey. Room shows the 27-foot corner glass sliders.
We are nearing the finish line with another True Net-Zero Energy Home, builder Shawn Harvey and home designer Dave Jenkins felt it’s a good time for an update! In our April blog, FGCU Students Meet Net-Zero Energy Home Experts you read about the exciting home that inspired FGCU professor Simeon Komisar PhD, to ask the home’s designer and builder to give a presentation to faculty and students. So excited are the home’s owners about their nearly completed Net-Zero Energy Home, Kathleen & Roy, and also their son Elliot an FGCU student, were instrumental in making the introduction.
While Energy Smart Home Plans owner Dave Jenkins has been involved in numerous Net-Zero Homes, including Lee County’s first True Net-Zero Energy Home. Designing and building such hi-performing marvels is not like falling off a log. In fact, it takes input from a number of experts to make them a reality. A home designer or architect that understands the importance of the HVAC system and have a general understanding of how the mechanical system works is a good start. A great hi-performance home builder like Shawn Harvey of Greencastle Inc. who is up on the latest building science techniques, is most essential. Also critical is a building science firm that provides the Room by Room Heat Load Calculations and also designs an optimized HVAC system. For a True Net-Zero Energy Home, they must also provide inspections along the way, the final blower door test and Net-Zero Energy Home commissioning.
LEFT: Blower Door Test. RIGHT: This is a secondary test, called a Duct Blaster Test, it checks for leakage in the duct work.
The Blower Door test measuring the air-tightness of the home was performed on 5-25-2018, by the North Venice, Florida building science firm, Calcs-Plus. As of January of this year, the Florida Building Code requires between 3 and 7 air exchanges per hour. The lower the number, the better. A fresh air intake is required if the home is any tighter than that. Builder Shawn Harvey builds some of the tightest homes tested and as he always plans for fresh air makeup. Kathleen & Roy’s Net-Zero Energy Home is no different. Even with a wall of over 27-feet of corner sliding glass doors, the home came in at 2.49 ACH-50.
Blower Door Test Description video by Shawn Harvey.
Of course none of this would be possible without the vision of Kathleen and Roy, who were committed from the start to have a truly sustainable “forever home.” We began the design in 2015 but due to complications, they had to postpone construction of their dream home till 2017. I’m very happy to report that the homeowner’s move in date is only a few days away!
We’ll be photographing the home shortly, so stay tuned to see how gorgeous a True Net-Zero Energy Home can be in our upcoming blog! For more information about this home plan see Tavernier on our website. The News-Press article on our True Net-Zero Energy Home in Fort Myers by Andrea Stetson is available on News-Press.com.