Our Path to Zero: Passive + Net Zero Home Design
Nineteen years ago, my husband and I moved from our co-op on the Upper West Side of Manhattan to a house in northern Westchester County that we designed. It was/ is a beautiful house, so beautiful that the only way we could sell it was knowing that we could design another house.
On February 12th we handed over the keys to the new owners. On that same day, we drove over the border to Connecticut to review with a surveyor a land parcel that will be the site of our second house design. Similar to our original land, it is a beautiful site, crisscrossed with stone walls, and surrounded by 50+ acres of conservation land owned by the Greenwich Riding Trails Association, the Nature Conservancy, and the Altschul Family Foundation.
Our goal for this house is to simplify: less land, less garden, less square footage, and, most importantly, less reliance on outside resources such as energy and water. To attain this we hope to design a house that will consume minimal energy from a source that we will provide.
Passive House vs. Net Zero-Energy House
There are choices when you are seeking to design an energy-efficient house. Passive House (Passivhaus) is based on a rigorous series of standards from Germany (modified to meet our unique climate) that, when implemented, results in a house that needs minimal energy to heat and cool it, or as my architect friend Elizabeth says, “a house that can be heated with a hairdryer.” The key to accomplishing this is insulation–insulating and sealing the house controls temperature. Due to this extreme insulation and sealing, minimizing substances in the air is crucial; contaminants such as gas for cooking and wood burning fireplaces aren’t allowed.
A Zero-Energy House is a house that is connected to the grid and uses an onsite energy source (solar panels for instance) which will generate enough power to heat and cool a home, resulting in a zero-energy bill. Zero-Energy homes also use the same principles of insulation found in Passive House design.
We plan to adapt principles from both concepts in designing our new house. Here are the ground rules:
Site orientation: the house will be sited to maximally leverage south and west light
Water: our water will come from a well that we dig
Small floor plate: square footage will be kept to a minimum to control energy consumption
Solar panels: the two bars of the house will have solar panels for our energy source
Insulation: 1 foot + walls consisting of 2 x 8 or 2 x 6 inch studs with cellulose insulation, additional exterior insulation, rain screen, and exterior cladding will comprise the enclosure of the house
Fenestration: airtight windows (It’s still hard to find American made windows; ours hopefully will be Unilux windows from Germany.)
Site Orientation Showing Stone Walls and Altschul Pond
As architects, my husband and I are excited and committed to plan our future by building a house that will reduce our carbon footprint and contribute even a small amount to saving our planet.