You know that a builder is committed to the future of housing when he develops four communities at one time and all the homes are zero energy or zero energy ready. Anthony Aebi, of Greenhill Contracting, Inc. has pioneered these zero energy home developments. Since 2007, he has built 29 new zero energy homes and one retrofitted zero energy ready certified home. These affordable zero energy and zero energy ready homes are in four developments in New Paltz, Gardiner, and Esopus, New York: Green Acres, the Preserve at Mountain Vista, Scenic Meadows, and the Homes of Esopus. Most of these homes are price comparable to similar standard homes in the area based on total cost of ownership.
All of Greenhill Contracting’s homes are designed and built to the highest energy efficiency and green building standards, including ENERGY STAR, EPA Indoor airPLUS, USGBC LEED for Homes, and DOE Zero Energy Ready Homes certification. Careful selection of building materials, HVAC equipment, water efficient fixtures, and appliances help create a synergistic relationship between occupant comfort, indoor air quality, and building efficiency. By reducing overall energy demand and selecting environmentally-preferred materials, Greenhill Contracting homes have a greatly reduced carbon footprint compared to a standard new home, with indoor air quality being a priority for every home it builds. And these homes are built to last hundreds of years, further increasing their sustainability.
Greenhill Contracting achieves net zero energy use in its homes by using photovoltaic solar panels and geothermal heating and cooling, combined with super insulation and air tightness. Insulated concrete form (ICF) walls, triple-pane glass, and heat recovery ventilation complete the system. As a result, Greenhill Contracting buildings consume less energy than they produce when occupied by an average family using an average amount of energy. The following systems work together to deliver high quality, zero energy homes.
- Geothermal heating and cooling with a ground source heat pump
- Solar (photovoltaic) panels
- Super insulation and air tightness using insulated concrete forms
- High-efficiency windows
- Efficient heat recovery ventilation
Greenhill Contracting homes are constructed with ICFs from the foundation to the roof, using Fox Blocks ICFs. Not only are ICFs air-tight, but the layers of polystyrene enveloping 6 inches of reinforced concrete have insulating properties of R-22, resulting in extremely strong, durable homes. According to Aebi, “these homes could last for hundreds of years, compared to many decades for standard homes, basically an order of magnitude longer, since they are are not susceptible to high winds, tornadoes and earthquakes.”
To complete the ground-to-roof, energy efficient thermal envelope, he uses more than twice the insulation beneath the slab than is required by Energy Star, specifically 4 inches of closed cell spray foam providing R-25, which provides a robust air sealing detail against soil gases. His windows – triple-paned, inert gas filled, low-E – exceed Energy Star performance criteria by at least 30%.
Due to the tremendous efficiencies gained by using the constant temperatures of the earth, a ground source heat pump (GSHP) provides all the heating and cooling needs for these homes, requiring far less electricity than more conventional systems. On smaller homes, the company uses high-efficiency air source heat pumps (ASHPs) instead of GSHPs. By combining ICFs for insulation and airtightness with the use of GSHPs or ASHPs, the energy needs of homes built by Greenhill Contracting are greatly reduced. These reduced energy needs are provided by south facing solar panels.
Greenhill Contracting has won a variety of awards over the last 5 years, including a 2012 BASF DOE Builders Challenge Award for maximum home performance for the first rated zero energy home in the Northeast, the New York State Research and Development Authority award for the builder with the lowest HERS index in New York State for 2012-13 and 2014-15. The company has also won RESNET awards for the lowest HERS score in 2015 and 2016, and the RESNET Net Zero Award in 2016 and 2017, as well as the PCA Resilience Leadership Award and the EPA Indoor AirPlus Leader award in 2016. And Greenhill Contracting received six DOE Zero Energy Home Innovation Awards in the past four years. The Department of Energy’s 2014 Zero Energy Home Innovation Award details Greenhill Contracting’s zero energy construction practices on their website.
Greenhill Contracting keeps cost for its zero energy homes low by using a simple, reproducible formula. While marketing its zero energy homes during the great recession was challenging, Aebi says the company has found that the most effective method for marketing these homes is to “sit people down and explain the value and hold their hands through the whole process. To do that you need a willing customer and a real estate agent willing and able to take on the challenge.”