Passive House BKLYN

Energy Revolution in a Brooklyn Townhome

Monthly Archives: September 2009

Community Board Approval!

We met with the Community Board Landmark Review Committee last week to show them our solution for the window replacement (Optiwin in the front with fixed upper sashes and tilt and turn lower and the Thermotech rear casement windows). They voted 9 to 2 in favor of allowing us to proceed to the Landmark Board (the city-wide Board with jurisdiction) with our design . We now have our Landmark Board presentation date set for Oct. 20th (right after the Passive House Conference Hopefully, we will have some sympathetic ears on the board, but I have already heard that their initial review of our windows is causing a stir.

Another exciting item that came out of the Community Board meeting was (after they voted on approving our design) a Board member made a motion to ask Landmark Preservation to look into the Passive House standards and adjust their charter to accept and work with the standards. This was unanimously approved. It might not hold much traction with the Landmark Board, but it was heartening to see that after just a short description of Passive House and what we were trying to achieve, we won over the community to our cause. We also have a mayor who appears very sympathetic to the sustainable movement and hopefully could weigh in on the case, if necessary in the end.


Modular Passive House Construction Video

This video showing the construction of a modular Passive House in Europe was just sent to me and is, I think, worthy of a view. If nothing else, it will make you envious about how quickly they were able to build the home.

Passive House in a Landmark District

Our project is located in Park Slope in a Landmark Preservation District. That means that any changes we make to the outside of the building that can be seen from any public street needs to gain approval from Landmark Preservation. While I am a strong proponent of Landmark Preservation in general terms, I feel that sometimes the individual rules are pushed too far and border on historical realism which should be something left to the theme parks.

We have recently run into some of these rules regarding window replacements. In order for our project to be a Passive House, we have to have a very, very good U-value performance (U-value is the inverse of R-value), a high SHGC (Solar Heat Gain Coefficient; varies in different climates and zones), and an airtight frame assembly. There are currently only two manufacturers of windows on this continent that just barely meet those requirements – Serious Windows (, and Thermotech Windows ( The problem is that both of these window makers make Fiberglass windows, because it is extremely difficult to make wood windows that have low enough U-Values to meet Passive House…which brings us back to Landmark Preservation. According to Landmarks, the windows must be the same material, operation, finish, glazing size, frame size, and division as the original windows. Therefore when we submitted to Landmark Preservation our super-insulated, triple pane, painted fiberglass windows as casements (with a foax bar in the middle to simulate double-hung windows) we were rejected at the staff level. We now have to do the full Community Board and Landmark Preservation Board meetings which is a multi-month process.

We have now changed the design with Optiwin Windows for the front and the Thermotech windows for the back. The Optiwin windows are being made and shipped directly from Germany and we are having to have the frames custom made to have a fixed upper sash and a tilt and turn lower sash that is staggered back to look like double-hung from the street. While the final bid for these windows is not in yet, the cost of the shipping itself is staggering. These are the only wood windows though that we could use to hopefully satisfy Landmarks as well as Passive House Standards. Luckily, we have a client who is deeply committed to the project and is willing to steer between these unfortunately conflicting requirements.

For me, this brings up a larger issue that we have to face very quickly as a society. Does it make sense for us to take a window in time and freeze it (as is the case of Landmark Preservation) at the expense of our ecosystem? I hope that the political pressure will build soon to make clear that our environment takes precedence over most other concerns. What will a beautiful street matter if there are no people able to live in it? It is my belief though, and I think this project when completed will help prove the point, that aesthetic considerations do not have to be sacrificed for environmental ones. Sustainable design has no one style, and I look forward to the day when we will no longer need to make the distinction between ‘Sustainable’ design and design itself.

Demolition Underway

As with all renovations of 120 year old buildings, once demolition starts, you find things that you wish were not there. Some of the issues that came up for us as the walls were being opened last week are multiple broken header beams at the staircase opening, cut joists in the bathroom floors, cloth wiring in many hidden junction boxes, furred out brick load bearing columns (that instead of three bricks have only one), plumbing that is a combination of lead, cast iron, copper, brass, PVC, and stainless steel all intermixed in random ways.

Despite the clients’ 10% contingency for the project being earmarked all within the first two weeks, we hopefully have been able to give the client peace of mind that they will be living in a house that is structurally sound, will not have leaking pipes, and the electrical wiring will not burn the house down after the renovation is complete. It always amazes me in these old homes how many safety risks people cover up behind the walls.

The First Passive House Townhouse Retrofit…

…is happening in Park Slope, Brooklyn.

Stay tuned to this blog to follow the construction progress as Prospect Architecture transforms a beautiful, 4-story brownstone into an even more beautiful and exceptionally energy efficient, Passive House Certified brownstone over the coming months. We hope to share with you all of our trials and triumphs – and enough details to make Passive House certification the goal for everyone embarking on a new construction or renovation house project.

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