Zero Net Energy Capable!
We are in the design phase of constructing our first Zero Net Energy capable home. In our last new home construction project our goals were more modest: we wanted to meet the unofficial standard for a super-insulated home as defined by the Building Science Corporation; and we wanted the house to be a Mass Save Tier III home, which would award the client a generous rebate from Mass Save. We met both those goals and did so within a pretty tight budget.
The house we are currently designing is for Jill and Michael, a Brooklyn couple who own a lot in the Berkshire town of Savoy; we will be building this house to an even higher performance standard. To be zero net energy capable, a house must be built with performance characteristics that allow it to generate as much energy as it consumes over the course of a year. It may pull power of the grid at times (at night, for example), but it makes up for that consumption by pouring power back into the grid during bright and sunny days. The house will require not only a properly sized solar electric grid, but also an extremely high performing building shell, one that allows for very little heat loss to the outside environment. Our goal is to build a shell that loses no more than 7-8 btu/hr-sqft. at peak heat loss, a target that should facilitate zero net energy capabilities. This level of performance will require greater air sealing efforts and better performing windows than our last project, which loses about 10-11 btu/hr-sqft in the coldest hours.
I will be writing more about this house as the design process unfolds. We are working in close collaboration with Hardwick Post and Beam, who is cutting and assembling the timber frame structure of the house. The current construction schedule has us breaking ground in June.