New project: ICF Passive House in River Forest

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

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

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

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

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

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

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.