Midwestern Sustainable Design

New project: ICF Passive House in River Forest

2012-02-06T15:31:00.001-06:00

I'm excited to share that I'm designing a new house (planned to be certified by PHIUS) for a wonderful young family, with a great team of builders. The owners asked for a home that would not only be super-energy-efficient, but extremely strong as well. They want a house that will last, and that will offer them psychological and physical comfort. Working with clients like this makes being an architect so rewarding.

When they said they wanted a very strong house (in fact they asked for concrete), I thought of my friend and associate Eric Barton of Biltmore Insulated Concrete, an ICF expert that took the Passive House Consultant Training with me (and recently passed his exams, congrats Eric). I also turned to Brandon Weiss of Weiss Building and Development, an award-winning green builder who focuses on building science and efficiency. Brandon will be the GC, Eric will handle the ICFs and most of the thermal shell. Having the complete team working toward a common vision is essential, so we're in a good position.

South wall

Schematic design is complete, and we plan to wrap up Design Development at the end of the week. Initial Annual Heating Demand is coming in under 4kBTU/s.f. yr., including most thermal bridging accounted for; when we get the documents together at the end of the week, the project will go off to PHIUS for pre-certification. After that, Andy Scott of Energistics will take over the rating part of the certification process. I'm going to cover the PHIUS+ process in some detail so those curious how it works can learn. Here are a few renderings of the in-process design.

Entry

Ultra-efficient retrofits: the next frontier

2011-06-30T16:33:00.001-05:00

I used to commute downtown to work, and would get on the El next to a freight line. On that line every morning ran trains with car after coal car full of coal. They were probably heading for the State Line Generation Plant, built in the '20's under order of Sam Insull. That old plant, allegedly impossible to retrofit with advanced pollution control technology, would burn that coal to send us power, along with sulfur dioxide and airborne mercury, not to mention the devastation it wrought on Lake Michigan. It hurt to think of my son and daughter breathing and swimming in the poison. Then my commute took me through Chicago's West Side, full of old uninsulated masonry buildings.

You know where this is headed: I was traveling through a huge opportunity that would have direct results on the health of my children and our local habitat. And this isn't limited to impoverished sections of the West Side--Oak Park is full of uninsulated houses as well. Every old suburb or city is. We have three impediments to rapid efficiency improvements: public education (think of how active the window replacement companies are--we need that for insulation and air sealing), a depressed housing market (little equity to draw on), and lack of financial incentives.

I have three projects (last year's, this year's, and next year's) to share in upcoming posts: a retrofit/addition in Geneva, which went from a HERS 175 (approx.) to 62; a retrofit/addition in Oak Park which will get to a HERS of about 53; and a Passive House retrofit in Chicago (HERS not yet calculated, probably around 25).

Rendering for visulaization

2011-04-07T18:50:00.003-05:00

I've been using the Podium rendering engine inside SketchUp lately for a few projects in Evanston:

This new kitchen in a Prairie Style house, and...

...this view showing a mudroom tile/railing/built-in transition. While both of these could get polished in Photoshop, these "out of the box" renderings let me communicate to homeowner and contractor quickly.

This blog has been focused mainly on passive house as an energy standard, but alongside PHPP, space, light, and material must be studied to bring all aspects of the design into focus simultaneously. These good 3D tools go a long way toward collaborative visualization.

First built example: functional PH, almost to certification

2010-11-10T10:02:00.002-06:00

We have just about completed construction on a house at 1122 Clinton Ave. in Oak Park, an ultra-efficient house designed using PHPP. Marko Spiegel of CTI and OneWatt Construction was the energy consultant and partner with Allen Drewes in the construction team. The owners kept an excellent blog (www.fourthickwalls.net ) that tracked the design and construction process. In the design process we came to a point where we had a choice between reaching PH certification by importing German windows, or getting close with much less expensive N. American windows. We chose the latter. Knowing what I know now, we could have adjusted the design (insulation amounts, glazing amounts, etc.) to make certification as well, but we were pretty far along, and the schedule was pressing. Still, we knew that the house would behave like a PH (super insulation, airtightness, balanced ventilation), but at about 15-20% above certification. It will be good to track performance and comfort as the owners settle in this winter. Here are a few photos:

Front view: note "loft" clerestory, south windows for solar access

Living Room: pellet stove for supplemental heat

Rear view: screen porch still to be built (on left)

The second floor bedrooms are arranged on the south for solar access; the north side has bathrooms, closets, and other rooms that don't need big windows. The house opens to the front and back, with porches to shade (preventing glare and overheating) and provide inside-outside connection. The siding is Hardie cement board, the roof is standing seam metal, the windows by Loewen (triple pane, Ug=.18).

When the photovoltaic solar array goes on, the HERS score of the house will be 26. Currently it's 35, 65% better than built-to-code. Although we all would have loved to have reached Passive House certification, the project is still a success: we integrated performance and design, integrated the house with its block and context, built a healthy, super-performing home, and had a great team experience and learned a lot through the process. We also have the opportunity to share our experiences so that others may benefit.

It's warm inside!

The balancing act

2010-10-18T18:35:00.001-05:00

Since completing the first half of Consultant Training, I worked on 3 new prototypes in an attempt to understand how to optimize Passive House design on what I now realize is a most challenging building type and site. First, the issue of compactness: a 20' house on 2 stories is relatively long, and therefore its surface-to-volume ratio is high, resulting in big heat losses. If you try to overcome those losses with big south windows, you soon overheat the house or cause an overly large cooling load: hence the balancing act. So you increase the insulation as high as possible and simplify the volume as much as possible. It's interesting to note that more insulation and simple volume means a less expensive building to build than a more complex one with lots of pricey windows!

After some wrangling with heroic amounts of insulation I managed to get the first new prototype to work, barely hitting the targets for heating, cooling, and primary energy use. This was a tiny house-- 3 bedrooms, treated floor area (TFA) 1284 s.f. (gross area about 1,600 s.f.), compactness of 3.4. It didn't have or need the big clerestory as in this blog's previous design.

For the next one, I tried an even simpler shape and 4 bedrooms, TFA 1,414, gross area 1,800 s.f., compactness of 3.2. This was slightly easier to bring to the energy targets. Then I tried a 3-story 4-bedroom version, TFA 1,781, gross area 2,400, compactness 3.1; this was easier still.

But "easier"-- it still means 16" of rigid insulation under the slab, 18" thick walls filled with insulation, R-100 roof, and the finest windows made. (There are many ways to get to compliance, but these are the ones I used.) It's evident that compactness really matters. That point came clear in training: our first exercise was a single family detached house, which we didn't quite get to certification in the Chicago climate. The next one was a 4-unit multi-family house, and it was, by comparison, a breeze.

As we look ahead to renewed development, particularly in transit-oriented districts, I think we're going to see many Passive House apartments, condos, duplexes, and townhomes. For minimal upcharge, fully offset by low operational costs, new homeowners will be able to live well, comfortably, and green. Looks like it's time for a multifamily prototype exercise!

PHPP: the real deal

2010-09-28T22:21:00.000-05:00

I'm in Urbana at the Passive House Consultant Training course, and am quickly realizing that my early attempts at PHPP calculations were just scratching the surface. Also a case of knowing "just enough to be dangerous." To make the annual heat requirement, I created huge southern glass areas, which, I found out, create huge daily temperature swings, will require lots of summer cooling, and (of course) are expensive. It's Tuesday, day 2 of 9, so there's much to learn...not to mention the years of learning to follow.

I will continue on the prototype development once I've completed the course...

Design development of the new Passive House prototype

2010-04-19T23:14:00.003-05:00

This is a continuation of previous discussion of the thermal envelope design per the Passive House Planning Package. The initial design studies were boxes, for simplicity and for efficient use of the narrow site. But does the passive house need to look boxy? Of course not. But its deviation from boxiness should be a result of spatial motives, and should not compromise performance. There are certain view and volume vectors that the site welcomes: forward, back, and up, in particular. Returning to the organic analogy, this creature will define itself relative to these: a two-faced being (we'll call her/him Janice/Janus), greeting neighbors on the street and the family in the back yard, and with great eyes to Jove above and south. (I don't really have a Roman thing going, but it turns out that Janus is also the patron of concrete, which warms an architect's heart.) The north side is the back, minimally punctured, a big blanket-wall, which folds to become roof above.

All these ideas are tumbling together in the sketchbook, of which this is probably about the sixth page:

Ideas about the south windows in the front living room turning the corner to open up the space; the house takes on an asymmetry that expresses its purpose and brings drama (p. 7-ish):

The entry sequence works with the compression of the site and sets up a big moment of light and space once the front door opens. I go into SketchUp to create the model, and here's a section of that space:

You can see how that north wall is receiving a lot of light (heat) and bouncing it back into the house; this shot is 12:30 on January 12. I also inserted some furniture into the model to test the spaces--the rooms are small, the house is small, but it still accommodates what we need (model shot in Spring):

To get a sense of the front composition, quantitatively determined by PHPP, and qualitatively determined by spatial and light qualities, I render it (using Podium, a SketchUp plug-in):

The odd zigzag in the front window is light falling on the interior stair. Here's an overview from the northwest:

The idea of the balconies is that they have a "green screen" growing wall for climbing plants--really grounding the house. The siding is cedar, in a rainscreen application, with steel copings and north wall/roof cladding. The green roof helps manage water, mitigates the heat island effect, extends the life of the roof, and saves energy. This is a quick study, and I feel it needs development in the porch elements especially, but overall I'm satisfied with a dynamic and expressive composition thoroughly based on performance. There is much to discuss with the cladding concepts, water management, site development, etc...some other time.

Our next step would be to move into ArchiCad, our "virtual building" program that is an integrated 3d parametric model with 2d document creation, where we generate all plans, details, schedules, etc.

PHPP as a design tool - part 2

2010-03-29T00:57:00.003-05:00

This is the follow-up to my first post. In PHPP I decided my first objective would be to analyze the thermal shell: overall building orientation, window, roof, and wall R-values, surface-to-volume ratio, window areas, window shading, etc., which all feed into a calculation of Specific Space Heat Demand. We're aiming for 4.75 kBTU/(ft2yr), the maximum SSHD to make passive house certification. I've been working on the 21st c. version of the bungalow, an urban house that is right-sized, reasonably affordable, and delightful. I wanted to know if I could also make it a Passive House.

Before I get into details, though, let me state that I haven't been through the PH Consultant training class; they haven't been offered in the Midwest since I became aware of them. The software, while complex, is fairly intuitive, at least to the extent I'm into it. At this point I'm looking mostly at space heating and not overall energy use (electrical loads haven't been considered, for instance), but it's enough to turn up some interesting insights.

I started with a few assumptions: approximately R-48 walls, R-60 roof, R-40 foundation, and triple-pane fiberglass windows and doors. Really high performance stuff by current US standards, but typical for Passive House. It's assumed that the house would have less than the maximum permissible .6 air changes per hour when pressurized to 50 Pascals (equivalent of having a 20 mph wind blowing on all sides of the house). Through earlier planning and energy analysis I arrived at a scheme with bedrooms in the lower level (floor 3' below grade), and living spaces above (about 6' above grade). It has a full-width front living room with side entry like many bungalows. Here's an overview of the volume from the northwest (remember the visual design elements will emerge from or alongside the analysis--not starting with visual preconceptions):

Note the "green garage" in the back!

Then I loaded up the south side with windows, put in generous east and west sliding doors for access to porches and yards, and ran the calculations. Here's the basic box from the west (like most Oak Park lots, ours runs E-W):

Strangely, when I ran the calculations on this without context or shading, I came up with 4.74 kBTU/(ft2yr), just barely making the Specific Space Heating Demand (SSHD). So I added context (which blocked out much of the solar gain)...

...and it jumped to 6.66 kBTU/(ft2yr). These images are from Oct. 15, about the beginning of heating season. That shadow on the south wall climbs for 2 months! I tried pumping up the insulation to crazy amounts, and couldn't get the SSHD to come close. That sunlight is just plain necessary. So what do you do on an urban lot with a neighbor to your south? You need a different shape. I was worried that adding a clerestory for sunlight would throw off my surface-to-volume ratio, but it was about my only option with this footprint:

Just loaded that south clerestory face entirely with windows. To my surprise, the SSHD came down to 4.68 kBTU/(ft2yr), even better than the single story house without neighbors. It was evident that adding the "right" volume could be a good thing. Before I added the clerestory, the house was 3 bedrooms, 2 baths. In the east portion of the clerestory I put a family/guest room, which gives some flexibility to the function of the house. The clerestory also provides a dynamic spatial experience at the entry/stair volume, in which you approach from the shaded north, then enter into space, light, and view to the sky, an underrated and guaranteed view.

The following image shows a general outline of porch and basic overhangs (to provide shelter from summer overheating and rain/snow, and to provide spatial continuity of interior to exterior):

When I look at the basic mass, I see continuity of scale with the gable-roof neighbors. This house can't be gable-roofed and perform as it needs to. The low-slope (almost flat) roof allows green roof, though, which has a host of benefits. In the next post I'll show development of the basic mass into something of architectural merit.

Paean to Design

2010-03-09T15:25:00.002-06:00

Most of us architects go into the field because of our love of design. As youngsters we visited a beautiful building or city, or in my case, picked up a book on Frank Lloyd Wright (in high school), have been building with blocks/legos/couch cushions in endless permutations for years, and draw, draw, draw...whether it's Wright or Gehry or Palladio that inspired us, we, too, want to create something great. We're convinced that design matters. There's a saying in preservation circles: "it's not good because it's old, it's old because it's good." The same case can be made for good design vs. mediocrity. A big part of sustainability, after all, is to build something that will stand the test of time! But then there's the next level, the one we really aspire to: design that has such a sense of timelessness, correctness, and beauty, that it takes on a life of its own, with the identity and importance of an organic entity. Not all buildings are meant to be foreground buildings or monuments, but even those that are part of a fabric can have this timeless or organic quality.

One of my inspirations is Japanese design, in part because of its purposeful handling of minimal elements, and in part because of the value placed on the garden/microcosm: no matter how small, there is a connection to a larger natural world. There is an enhanced sense of meaning when extraneous elements are pared away, and the necessary elements are well wrought. I'll never forget the day, about in the middle of my year at Taliesin West, that I realized how fundamental Wright's desert buildings were: there was no veneer, no extra layers, the rambling compound perfectly fit the site, and it was built of local materials; it felt like the earth speaking through architecture. The same sense you get in Chartres. Is there any reason we shouldn't have this in our homes and businesses? Does it cost more? No, but it takes inspiration, time, and care. It takes design.

Using PHPP as a design tool: p.1

2010-03-05T17:47:00.005-06:00

Here's a big question about architectural design: Should building form start with a sculptural idea/preconception about "style," or should it follow from something more rigorous? A leading question, of course. If only we had a tool that would provide a clear and rigorous standard whereby form could be judged by its performance...using an organic analogy, if the building were an animal, it would find the right spot on the site to suit its thermal needs, would adjust its surface-to-volume ratio accordingly (think of the cat stretched out in summer, but curled up in winter), would have an appropriate skin for the elements, and so on. The right design tool would help determine that sweet spot for any given climate and site.

PHPP is the Passive House Planning Package, software developed by the Passivhaus Institute (see the PHIUS link on the sidebar for info), that allows the designer to predict energy consumption, heat loss, passive solar gain, thermal bridging, and a host of factors that influence building performance. Since 1991 the tool has been developed to provide great accuracy of prediction. Use of the software is required to design to Passive House certification. I bought the software shortly after attending the Passive House US Conference in October 2009, but haven't yet been able to attend a Consultant training class.

My first task with the software was to try different building configurations on my test lot--my own 30'x126' lot in Oak Park-- to see how certain design decisions would affect overall performance, especially the target of 4.75kBTU/s.f.A for space heating.

With a tool like PHPP, the "organism's" shape, orientation, and location can be situated for its site. The art of architecture is to tranform that high-performance shape into inspiring form, create beautiful interior spaces and natural light, and make visual and spatial connections to the outdoors. My upcoming posts will document some of my trials. For a teaser, here's a rendering of one of the test prototypes: