Located on 13 acres in New Haven, VT Doug and Ruth M. built a south-facing home for passive solar in 2007 with a roof designed for photovoltaic (PV) solar panels. The large windows, especially in the breakfast nook with a wide view from the eastern to western horizons, allow for the home to collect heat as the sun shines through and retains it in a thermal mass. They also added honeycomb cellular shades to help reduce their energy costs throughout the house and to create more window insulation for their tightly sealed home. After their home was built, Doug and Ruth obtained a Home Energy Rating System (HERS) certification of 54 when they had the home’s energy efficiency measured. A good HERS rating is around 80-100, and the lower the number, the more energy efficient the home is!
Ductless Mini Split
Along with large windows, tightly sealed crevices, and facing the south, Doug and Ruth didn’t stop there. They removed the backup propane fireplace and opted for a heat pump, also known as a ductless mini split. This system has two units; one outdoor and one indoor unit mounted to a wall. They’re connected by refrigerant tubing and electrical wiring. The best part is, there’s no ductwork needed which also saves them more than 30% in energy consumption. The mini split heats and cools the air with the push of a button.
Heat Recovery Ventilator
In addition to the ductless mini splits, Doug and Ruth added two air ducts on the outside of the house, one that carries fresh air into their home, and one that carries stale air out. These ducts supply a heat recovery ventilator (HRV) and these help make homes healthier, cleaner, and more comfortable. Not only does an HRV system bring in the fresh air, but it also gets rid of many pollutants in your home like excess moisture, molds, household chemicals, and bacteria. Since installing the system, it has given them fresher air in their tight home and reduced heat loss!
In 2010, Building Energy installed a 5 kW solar system with 22 panels rated at 230 watts each. 12 years later, we upgraded the system to a newer inverter with more features like online data monitoring and the ability to power the house independently from the grid. Additionally, 2 more solar panels that are 400 watts each were added, and a 260-pound 10 kilowatt-an-hour SolarEdge battery. For a bigger picture, each kW of electricity generated by Doug and Ruth’s solar panels reduces the need for dirty energy sources like coal, gas, and other fossil fuels. This system will produce about 6600 kWh per year, which is the equivalent of planting 77 new trees!
A solar system is only as good as its inverter and that is why we chose the SolarEdge battery. This is a great option for a few reasons. First, the efficiency rating of 99.2% is industry-leading and will result in significant additional savings over the life of the system. The sophisticated internet data monitoring included with the inverter gives Doug and Ruth the ability to view the performance of their system in real-time from a device connected to the internet. SolarEdge alerts us here at Building Energy if there are any faults in the system or if one of the panels is underperforming.
Doug and Ruth’s home has been using as much energy as it generates, making it net zero on an annual basis since 2007!
If you are considering solar, heat pumps, weatherization, insulation, or construction, contact us to schedule a free estimate!
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