“There is hardly any architectural competition where a double-façade is not presented with fancy words such as Synergistic Façade, Intelligent Façade, High-tech Façade, etc. An expert must ask, when these impressive words are pushed aside, whether these promises can be realized and achieved?” —Karl Gertis, Director of Fraunhofer-Instituts of Bauphysik, Stuttgart, Germany, 1999.

Round table at Southern California Edison

Fashion or Trend?

The following premise was used to stimulate discussion:

• Claims without substance dominate the architectural press.
• Fashion is the driving force: transparent architecture and all-glass buildings, not environmentalism.
• Performance rationalizations are given after the fact, such as environmental architecture, improved performance, sustainability, LEED ratings, or occupant amenity.
• Problem: If fashion is dictating this all-glass trend, then motivation to deliver high performance is low.

Please click HERE to view the questionnaire (MS Word - 79 KB)

Survey results

A single-page survey form was given to attendees to fill out after the discussion of this topic. The survey asked the respondent to rate various reasons why advanced façade systems might be considered for a commercial building project. The rating system was presented as a series of boxes to check with labels from 1 to 5, where 1 was labeled “unimportant” and 5 was labeled “critically important”. Boxes 2 through 4 were unlabeled, so for the purposes of this discussion, we will call a rating of 4 “somewhat important”, 3 “important”, and 2 “somewhat unimportant.” A rating of 0 indicated no response to a particular reason.

Nine options were given on the survey form as reasons to use advanced façades (see Figure). The options of citing and rating other reasons were also given. Of the total responses (n=22), the following was determined:

• 36% (n=8) thought that a strong interest to deliver a high-performance product was a critically important (rating=5) reason to use advanced façades, while another 50% (n=11) thought that this same reason was somewhat important (rating=4).
• 32% (n=7) thought that energy-efficiency was a critically important (rating=5) reason to use advanced façades, while another 45% (n=10) thought that this same reason was somewhat important (rating=4).
• 45% (n=10) thought that occupant amenity, indoor air quality, and access to daylight were critically important (rating=5) reasons to use advanced façades.
• 55% (n=12) thought that design aesthetics were a somewhat important (rating=4) reason to use advanced façades.
• 45% (n=10) thought that sustainability and LEEDS were a somewhat important (rating=4) reason to use advanced façades, while one person cited that the image of sustainability was critically important (rating=5).
• 41% (n=9) thought that either mandatory requirement by the client, competitive edge against other firms, or site or design aesthetic forces creative solutions were somewhat important (rating=4) reasons to use advanced façades.

These results strongly refute our earlier challenge/premise that the use of daylighting, solar control, double-envelope systems, natural ventilation, or active façade systems such as those seen in the architectural press are governed by style or fashion. The top three bullets all address motivations or reasons based on performance, not style. The top two bullets show that 77- 86% of the respondents believe that high-performance and energy-efficiency were either critically important (rating=5) or somewhat important (rating=4) reasons to use advanced façades. Design aesthetics did come into play as a strong motivation: 55% believed that this reason was somewhat important (rating=4) for use of advanced façades.

There may be a strong bias since this round table discussion was instigated by a National Laboratory whose known mission is energy-efficiency and improving the performance in buildings and because it may be difficult, even in the privacy of filling out a survey form, to admit that architectural decisions to use a particular design approach is dictated by fashion or a trend. Individual’s quotes below indicate the diversity of responses received.

Note: Please click on the picture for a printable version of this graph

Individual Responses

The discussion at the round table reflected the survey responses to some degree. Respondents did not come forth and state that advanced façades were based primarily on high-performance goals. Most stated that the use of advanced façades was based on a complex mix of design aesthetics, the desire for improved environmental quality, striving for at least an image of sustainability, and pragmatic economics.

From an academic or purely architectural perspective, the use of all-glass façades combined with advanced technological solutions is a rich, modern expression of form and function. James Carpenter spoke about this aesthetic in his afternoon talk (see below).

“I think that it is less an issue of fashion, per se, for the architect. For architects, the façade is really one of the last components of the building that is really left to their design capability, the one area that you focus on in a building. Simultaneously, it has been promoted in terms of glass performance over the last 10 to 15 years — the performance of the glass itself is improving to such an extent. I just think that it is a natural sort of convergence of glass industry initiatives in terms of the low-E and super low-E and double silvers. Certainly there is an underlying energy rationale. I think that fashion is perhaps the wrong term. Fashion means to me more style or something of that sort. I think that this is really a more earnest initiative in terms of design. Where do you apply your design skills? Are you applying it for style or are you applying it in a way that it has a real sort of contribution to the benefit of the building? There are people that might pursue it as fashion, but I don’t think that is what has been motivating it to date.” — Designer

Others conceded that advanced façades are popular because these façades convey a readily identifiable image or new design aesthetic of environmentalism and sustainability. Clients who wish to present an image of environmental stewardship look to the façade as a means of communicating this image.

“Our clients wanted to be a leader in terms of technology. They wanted to let everyone look at an example of it and say “What is that?” in order to get some kind of consciousness of what they were trying to do in terms of energy and better work environments. It wasn’t all image, but they wanted to have the representation of being a leader, of trying something… They wanted to try some things and be the first to really push that kind of technology.” — Architect on use of double-skin façade

“For most of these systems, the payback is so long term that it really has to be for other reasons. That is why – maybe fashion or whatever the right term is – you will see more buildings take on this type of technology: purely because it is sort of a corporate statement they are trying to make. They can acknowledge that payback is somewhat irrelevant.” — Engineer

“Most of our clients are interested in sustainability, but how much will they pay for that is the question. Generally, when you start to look at these advanced façades, they cost a lot more than conventional façades and the pay-back becomes very questionable. What it comes down to is whether that difference in payback can be justified with the image of sustainability that the client can use as a type of advertising cost. It only works if people can see it. If you can’t look at the building and see that there is something about it and that is sort of a reflection of the sustainability, then there is not as much interest in it. So if you end up with a wall that looks just like a conventional wall, even though it may be more cost effective and just as sustainable as one that is more spectacular, it does not work in the total equation.” — Architect

“So there is no problem within the architectural and engineering profession if the façade is conveying the image of sustainability and the building delivers on the image. The potential problem is that it conveys the image but it does not deliver. People are uncomfortable and the energy bills are high.” — Researcher

“The question of image comes to bear if you look at the market for the reha-bilitation of 60’s and 70’s speculative office buildings where all the window walls are coming due. A commercial building is valued by its façade design, its lobby, its elevator lobbies, and elevator cab, and then, of course, by performance. One that comes to mind is an old building which went from a half-rented, smelly old building to a Class “A” building that is fully rented and in demand just because of the façade and those other elements. This can be done with half the cost of a new building, but what is even more important is that you can’t build in those same places with that same kind of building volume anymore.” — Architect

Some respondents explained that the trend started in Europe with the intent to deliver high-performance based on strict codes and standards for environmental quality (despite earlier buildings actually perhaps failing to deliver the stated performance). The current trend in Europe after the rage of double-skin façades being erected in the 1990s is more pragmatic, focusing on following through on performance claims. In the U.S., however, there is the “bandwagon” effect, where architects are interested in using such façade systems but there is general confusion as to the applicability of these façade types to different climate zones and building types. Engineers are able to convince the client to use such systems, based on improved environmental quality for instance, but then have the obligation of following through on such claims.

“In the first ten years [of the use of double-skin façades in Europe], these advanced façades were realized by star architects. It was a type of fashion so there was typically no discussion about costs. If you look at the RWE Tower (see Building Case Studies), it was not designed so that the additional cost would have to be paid back. It was more of a showcase: an advanced image of the company behind the façade. This was related to big names in architecture. Nowadays, unknown architects and investors are looking for this type of advanced façade for their new buildings. Now, suddenly, the cost factor comes in because they ask, “What will I have to pay in added costs and when will I get it back?” Now, by investing in the façade, you have to save in the mechanical system. Otherwise, it is really ridiculous to have both a double façade and a mechanical system — you are investing in both. So the client comes back and asks “Why?” or says “Just eliminate this advanced façade and keep the mechanical system.” It is clear that the additional investment in the façade has to pay for a reduction in the mechanical system. In Europe, if you design the building correctly, you don’t need mechanical ventilation or mechanical cooling and this depends a lot on the façade. If you do a good façade, you are done with all aspects. With unknown investors, they say “OK, with the competition in the market, it looks like we have to offer a heated, cooled, ventilated building at a minimal cost.” — Engineer

"I think that we must recognize that there are psychological and sociological factors involved in the development of double-wall (airflow) façades in Europe - from a climate standpoint and the desire to have natural ventilation, to bringing more daylight into the workplace with more transparent façades. With natural ventilation, there are acoustical considerations to be dealt with as well as wind gusts and turbulence on façades that can be transferred to interior spaces unless they are tempered through the use of double-wall façades. When bringing this technology to the U.S., one must consider the significant climate differences from region to region as well as economic issues from a developer standpoint. Although these façades have the appearance of "high tech" and some may view their introduction into the U.S. as a trend with everyone trying to jump on the bandwagon, I believe their introduction is to try and get as much transparency in a building while meeting new energy codes. You can do a double-skin façade in a 50% opaque wall but I don't think that is the intent or direction architects will be going." - Architect

“I think that it is difficult in any of these discussions to nail down one system — the mechanical system or the façade — and attribute comfort to it, because obviously all these parts of the building are integrated and attribute to comfort. One believes that advanced façades do give better perceived comfort and I think that it has been demonstrated. Especially with the double-skin façade having ventilation and keeping surface temperatures very close to the mean radiant temperature of the room and thereby increasing your perceived level of comfort. Our clients have expressed an interest in that and these arguments have been successful. I think that in general what we are seeing is the tie back to this cost issue. Each of these projects requires substantial upfront effort on the part of the designer — which is why the term fashion is somewhat difficult to swallow. Fashion obviously won’t build your building. We have to be fiscally responsible with our projects and our client’s money, so it takes both the design, analysis and the engineering and then of course the financial engineering in the end, which is the biggest component that we try to provide our clients, to understand the total impact of the system over the life of the building, not just a simple payback.” — Engineer

Question/Information: eslee@lbl.gov