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Daylighting – A Brief Look at Systems, Benefits & Costs

It feels great to get outside on a beautiful day to go on a hike, bike ride or even a lazy walk around the neighborhood. Along with exercise, much of the energy a person gains from outdoor activity comes from getting some sun -it’s great for mind, body & soul! However too much sun isn’t a good thing for your skin, so you better wear some SPF? Good indoor daylight is healthy too, both for buildings and their occupants. However, as mindful as people are of getting too much outdoor sun, attention also needs to be applied to how building interiors receive sun. Done carefully, daylight can be brought inside with many benefits, in economic, environmental, and human terms. According to the Whole Building Design Guide, daylighting is defined as “the controlled admission of natural light – direct sunlight and diffuse skylight – into a building to reduce electric lighting and saving energy. …daylighting helps create a visually stimulating and productive environment for building occupants, while reducing as much as one-third of total building energy costs.” Benefits, depending on building type and use, in clude energy savings, increased worker productivity, increased retail sales, decreased absenteeism, boosted test scores for students, and accelerated recovery for hospital patients. With all of daylighting’s benefits, it is important to be done as a holistic system that provides daylight without excessive solar heat gain or glare. If not, it is possible to see actually higher energy costs than if daylighting had not been attempted. Let’s take a brief look at some of the techniques and components of a good daylighting system.

The WBDG describes daylighting as a system consisting of “systems, technologies, and architecture” including at least one of the following:

Daylight-optimized building footprint
Climate-responsive window-to-wall area ratio
High-performance glazing
Daylighting-optimized fenestration (windows etc.) design
Skylights (passive or active)
Tubular daylight devices
Daylight redirection devices
Solar shading devices
Daylight-responsive electric lighting controls
Daylight-optimized interior design (such as furniture design, space planning, and room surface finishes).

The footprint of the building is a critical daylighting component that cannot be retrofitted, so it must be planned for daylighting from the beginning. An east-west building axis provides a southern exposure that maximizes energy efficient daylighting opportunities. The south-to-north depth of the building is also important because the strength of the light decreases the further is travels into a space. As an example, daylight provided by a typical arrangement of windows for an office will provide sufficient daylight for a distance of up to 15’ into a space. (From an AIA 2030 workshop presented by Ihab Elzeyadi, Ph.D, FEIA, LEED AP, University of Oregon’s Department of Architecture). As additional daylighting components and strategies are added to the building design, daylighting can be effective for up to 60’ of floor depth south-to-north. Let’s break down a daylighting system and look at the individual components.

Dramatic, but not necessarily good daylighting strategy. The 1949 Philip Johnson Glass House would be difficult to pass current Title-24 energy requirements. The glazing must be around R2, but I’ll have to research that. Located in New Canaan Connecticut, I would like o know what it was like in the winter. My guess: beautiful but maybe a bit chilly until the fireplace got roaring.
http://en.wikipedia.org/wiki/File:Glasshouse-philip-johnson.jpg

Small windows can frame great views. View of San Francisco’s Coit Tower. Russian Hill Apartment, Zack de Vito Architecture + Construction, Photo credit: Bruce Damonte, http://www.zackdevito.com/markets/1-live/projects/48-russian-hill-high-rise

Windows are an obvious source of sunlight, but not always looked at as a daylighting component. Strategies for windows are critical to the effectiveness of the daylighting system. Many factors apply to windows and their placement – perhaps the most important is the window-to-wall area ratio because windows have very little insulating value compared to wood wall framing. Typical dual-pane window R-values range from R2 to R4, while 2×6 wood wall framing is typically insulated to R19. Large areas of glazing will let in a lot of light, but the building’s HVAC system will have to work hard to maintain comfortable indoor temperatures. Windows can be categorized in two ways – view windows and daylight-emitting windows. View windows are important to occupant satisfaction. According to Elzeyadi, “Those in offices with highly rated views used 20% less hours of sick leave.” “Employees used 30% less sick leave in offices with high daylighting quality.” Great views do not necessarily need to rely on large, energy-inefficient windows – smaller windows that frame views can add drama and demonstrate sophistication. Daylighting windows are usually placed high in walls, sometimes over view windows and are usually referred to as clearstory windows. Solar orientation is an

Large windows are most energy efficient on south-facing facades. Pala-Temecula House, 2003, MS|Architecture, Photo: Micah Smith

important factor when sizing and placing both view and daylighting windows. Energy Star labels on windows highlight other important factors: U-factor, Solar Heat Gain Coefficient, Visible Transmittance, and Air Leakage. These performance ratings should be matched to climate, solar orientation, and whether the window’s purpose is view or daylighting. Elzeyadi includes windows in a category called Side Lighting, where Top Lighting consists of skylights, roof monitors and other overhead daylight sources.

Saw tooth and raised roof monitors. http://www.public.asu.edu/~kroel/www558/Supriya%20and%20Kavish%20assign%203.pdf

Top lighting components like skylights and tubular daylight devices are familiar and often used in residential construction. However skylights are also great choices for retail and industrial buildings, especially “big-box” single story buildings. A PGE study of a major big-box retailer found skylights could be attributed to as much as a 40% increase in sales. Customers who were interviewed identified skylit stores as “airy, clean feeling,” and may tend to spend more time shopping. Another more obvious economic benefit of skylights is energy savings because of reduced reliance on artificial lighting. The same benefits also apply to smaller retail spaces. Skylights have a reputation for leaking, but modern skylights are quite reliable when correctly installed. Also they can be insulated with dual layers of glazing and some are operable for ventilation. Tubular daylighting devices are another great option. They require less space, are easily retrofitted to existing structures, and some models incorporate exhaust fans and electrical lights for night use. On a different scale, atria can facilitate large, dramatic daylit spaces. Width-to-height proportions, overall height, and interior layout and finishes are important factors to atrium design. Roof monitors are another option, if a bit less common than skylights. Actually in the first half of the 20^th century roof monitors were widely used in large industrial buildings. In the 1950s cheap fluorescent lighting and air-conditioning reduced the need for daylighting and roof monitors became obsolete. Having regained some popularity, roof monitors are usually incorporated into the roof structure and help define the architectural form of a building. They are often arranged with one or more rows of sawtooth-profiled ridges – each having a sloped side and a north-facing vertical side where windows are placed. As with windows, sun angles and solar orientation are important factors for roof monitors.

Good use of clearstory, lightshelf, and reflective ceiling and wall finishes. Los Angeles, Architects: A. Quincy Jones, Whitney R. Smith, Cory Buckner, Architect, 2004, Photo: Darcy Hemley http://www.dwell.com/house-tours/slideshow/mutual-fulfilment#4

Regulating daylight quantity and quality is critical, as is solar heat gain. Direct summer daylight can be blocked with shading devices, which in turn, allow direct winter daylight in to provide more direct daylight and warmth. As with windows, studies of sun angles and solar orientation can inform the design of correct type, size and placement of shading devices. Common types of shading devices include roof overhangs, awnings, vertical fins, and louvers. Roof monitors can received these treatments as well. Landscaping such as trees are also useful when placed strategically with respect to solar orientation and window location. Deciduous trees keep leaves in the summer providing shade, while in the winter the loss of leaves provides direct daylight and solar heat. Direct daylight that is brought into a space through clearstory windows can be redirected by lightshelves or interior louvers that bounce light off the ceiling. This will reduce glare and increase ambient daylight further into the space.

Daylighting-responsive electric lighting controls are critical to a daylighting system’s performance. Zoned lighting, dimmers, and photocell censors allow electrical lighting to dim or turn off when daylight is sufficiently illuminating a space. A study of office buildings by the American Council for an Energy-Efficient Economy shows that by “adding dimmable ballasts, photosensors, and occupancy controls where appropriate, with network components,” lighting energy consumption can be reduced by 50% or more. The study assumes an additional energy savings of 20% for reduced cooling loads due to lower light fixture-generated heat.

Circulation space adjacent to south-facing wall. http://www.wbdg.org/resources/daylighting.php

Circulation space adjacent to south-facing wall. Illustration by RNL Design. http://www.wbdg.org/resources/daylighting.php

As a daylighting component, interior design may be less obvious but it is significant. The WBDG lists furniture design, placement, and room surface finishes as important daylighting considerations. As an example, office cubicles that are shorter or that have transparent upper dividers help light travel deeper into office spaces. Also consider having circulation space near bright, south-facing windows, rather than locating workspaces directly under them. This will reduce the need for shading devices and will provide better light levels for those workspaces. In terms of interior finishes, light/glossy surfaces reflect light, and dark/matte surfaces absorb light. Ceilings are the most important surface for reflecting light, and floor reflectance is least important.

Because daylighting is a holistic system, all components must be correctly set up and maintained for the life of the building. The WBDG states that improper system installation & setup, referred to as commissioning, “is the most common reason for a daylighting system to fail.” For example, correct setup and maintenance of the daylight-responsive lighting controls will provide the energy savings they were designed to deliver. Landscape design and maintenance also play a role. This requires that building owners, occupants, and maintenance personnel are familiar with the intent and proper use of the entire daylighting system.

Lighting accounts for 17% of electrical consumption in the residential and commercial sectors, according to the US Energy Information Administration. Broken down by sector, those numbers are 13% for residential and 21% for commercial. Those energy costs can be reduced by 50% or more quite easily according to ACE3. Benefits can be accounted for in terms of increased sales, worker productivity, occupant health, and reduced resource utilization. But what does achieving those benefits cost a building owner? The answer will vary widely for every project depending mostly on choices made early on in the design. Reducing a window size reduces cost; a window glazing treatment will add cost. Providing a south-facing façade may not cost anything, or it may not be feasible at all. The ACE3 study is based on a $0.75/s.f. -incremental cost estimate for daylight-responsive lighting controls that generate lighting-related energy savings of 50% or more. A well-defined budget is critical to have in place before any design takes place. Preliminary cost estimates for a building construction can and should be prepared after the design, design development, and construction document phases, although I have not seen it done regularly in practice. Building maintenance costs can also be estimated. I welcome the opportunity to include this service in any project, but it requires coordination of the owner, design team (architect, engineers) and contractor from the beginning. From a developer perspective, marketplace considerations should be weighed against cost. Often tenants will pay more for a high-performing lease space.

Solar study for a residence by Paul Poirier, + Associates, Architects, use with permission from Paul Poirier, Architect www.poirierandassociates.com

Solar study for a residence by Paul Poirier + Associates, Architects, used with permission from Paul Poirier, Architect www.poirierandassociates.com

While daylighting is an important architectural design concept, the strategies used must be carefully applied to the overall project in a way that feels natural and unforced. The daylighting components chosen and how they are used should be appropriate to a particular client, style, location, climate, budget and other factors that inform the overall design, creating a building unique to its circumstance. If you have any questions about daylighting or have a project to discuss, please contact me – I look forward to hearing from you!

History of Architecture – Ancient Greece

Recently I completed a course in History of Architecture – Arch218 at Cal Poly San Luis Obispo, which I took for professional development as well as an obvious interest in the subject. I loved the class and want to follow up with a blog to help me retain what I learned and share it with others. So if you are interested in joining me, I am setting out to retrace the “course of architectural history!” I will be going back to my lecture notes, text books, and web links to provide a series of blog posts relating to each of the lectures that covers the Middle Ages (~1200 CE) to the Industrial Revolution (~ 1800 CE). My first two posts in this series will look briefly at the Classical eras of Greek and Roman architecture because these two epochs are fundamental to a discussion of subsequent European architectural history. Classic Greek and Roman architecture has influenced many styles including Romanesque, Renaissance, Baroque, and Neoclassical.

Greece was a powerful maritime empire in the Mediterranean in the 6^th century BCE when they began to use stone construction. Previously Greeks built mostly wooden and mud-brick structures but became influenced by the monumental stone structures of the Egyptians, who were trade partners. The wealth accumulated by various Greek colonies from trade contributed to the construction of monumental stone temples. Most Greek temples were built in Greek colonies throughout the Mediterranean and beyond, and to a lesser degree in mainland Greece. The decline and eventual end of large Greek temple construction came over the 3^rd through 1^st centuries BCE as political and economic power shifted toward the Roman Empire.

Reconstruction of the west facade of the Temple of Artemis, 600-580 BCE, Korkyra (Corfu)
Photo Credit http://www.mlahanas.de/Greeks/Arts/CorfuArtemis/CorfuTemplePlan.jpg}Image

Sculptures from the Pediment of the Temple of Artemis at the Archaeological Museum in Corfu
photo credit: http://en.wikipedia.org/wiki/File:Gorgon_at_the_Archaeological_Museum_in_Corfu.jpg

Rendering of an ancient Greek architectural paint scheme. photo credit: http://en.wikipedia.org/wiki/Ancient_Greek_art

Example of ancient Greek architectural paint scheme. photo credit: http://en.wikipedia.org/wiki/Ancient_Greek_art

The first example of a stone Doric temple (a-la the Parthenon) was the Temple of Artemis at Corfu, 600-580 BCE. This stone temple, now in ruins, had a triangular rooftop called a pediment, supported by the Doric order of columns, architrave, frieze and cornice that became common in Greek and Roman architecture. Although typical images of Greek temples are of monochromatic stone, they had brightly painted details – especially at the frieze. However, centuries of weathering has faded nearly all of the color.

Typical plan for a Greek temple http://www.thewaxtablet.com/2012/02/08/the-ancient-greek-temple-an-introduction-to-architectural-layouts/

The basic elements of the Greek temple floor plan are the naos (central structure housing a statue of the god the temple was built for), the pronaos (front porch extension of the naos), the opisthodomos (back porch extension of the naos), and the peristasis, which is the series of columns surrounding the central structure. One very notable Greek construction technique is the use of optical refinements throughout a temple structure. These refinements included a slight upward curve of the temple base or stylobate, as well as the architrave above. Columns are each shaped with an entasis, or a reduction in diameter as they rise. The columns also tilt slightly inward, especially at the corners, and are spaced slightly closer together at the corners than in the middle of the peristasis. Together these refinements help produce a much more dynamic and stout appearance when compared to more recent Neoclassical or Greek Revival buildings that borrow from Ancient Greece. Compare the British Museum in London with the Parthenon, which may be the best example of Greek optical refinement.

An exaggerated illustration of the Parthenon’s optical refinements. Photo credit: http://en.wikipedia.org/wiki/File:Opticorr.JPG

The British Museum, London. The facade is an obvious copy of the Parthenon, but the Greek Revival building appears more stiff and weaker at the columns. Photo credit: http://world-placez.blogspot.com/2013/02/British-Museum-England-Info.html

The Parthenon, as rough as it is now, still appears stout. Photo credit: http://archidialog.com/2011/01/16/david-chipperfield-oscar-niemeyer-the-parthenon-conscious-inspiration/

The Parthenon, a temple for the patron goddess Athena, is located on the Acropolis of Athens. Built in the 5^th century BCE, it is maybe the most important remaining Classic Greek building and the height of the Doric order. Originally a temple, It has also served as a Greek treasury, a Christian church, an Ottoman mosque, and an Ottoman ammunition depot. Because Greece became a Byzantine (later an Ottoman) territory, it was politically closed to Western Europe for centuries. It was not until the end of the 18^th century that the ancient Greek architecture of Athens was “rediscovered” due to a more politically open Ottoman Empire.

Parthenon restoration. Photo credit: http://www.ronsaari.com/stockImages/greece/AthensParthenon1.php

The Parthenon, 447-32 BCE, is the iconic Greek temple. Unfortunately today it is largely in ruins, although It was a mostly intact until 1687 when it was bombarded by the Venetians. Most of the damage was actually caused by the fact the Ottomans were using the Parthenon as an ammunition depot, which may have been why the building was targeted. The explosion blew the roof off the building and nearly destroyed it completely. More controversy occurred in 1806 when the Ottomans allowed the British ambassador, the Earl of Elgin, to take a majority of the ancient Greek frieze that adorned the top of the Pantheon. Many of those sculptures, known as the Elgin Marbles or Parthenon Marbles, are now displayed in London’s British Museum, but Greece has repeatedly asked for their return and has even built a museum to display them if/when they are returned. A recently completed partial restoration of the Parthenon took over 30 years, using original pieces where possible and new marble (from the original quarry) where needed. It is amazing to think it took less than 9 years to build the original structure (plus a few more years for decoration).

Although ancient Greek architecture heavily influenced Roman architecture, the two styles are different in many ways. The Romans were influence by Greece as well as other ancient peoples, but used their own building types, spaces and forms to reflect their civic-oriented culture and city planning. Thank you for reading and please come back soon for my next post in this series on ancient Roman architecture. In the mean time check out this terrific Nova episode “Secrets of the Parthenon” and this Chicago Tribune photo gallery of the restoration.

Aging in Place – Your Home Can Age Gracefully Too!

I have been able to spend a fair amount of time with my parents in recent years as they have moved, part-time, to the San Luis Obispo area. Recently I am noticing my mother having more and more difficulty with her mobility. As an architect with some understanding of accessible design, it is difficult seeing her struggle with mobility in her own home. Fortunately most homes, including my parents, can be adapted for improved accessibility. My parents, along with many other households, face decisions on adaptation of their home. The US Census Bureau provides statistics that help illustrate how many people we are talking about.

The 2010 US Census reports that 13% of the population is age 65 and over, but that demographic is growing. The 2000 Census 65-and-over population of 35 million increased to 40 million for the 2010 Census (a 15% increase) and the 2020 projection is for 55 million (a 36% increase for that decade). The 2010 Census also shows that for those age 65-69, nearly 25% report severe disability. Of course that rate increases by age – see Figure 1 below. More and more of us will have to adapt our homes for accessibility if we want to maintain a comfortable standard of living. So what can we do to facilitate aging in place?

Disability Prevalence by Age, from Americans With Disabilities: 2010, Matthew W. Brault, 2012 http://www.census.gov/prod/2012pubs/p70-131.pdf

There are different levels of adaptation to consider depending on many factors including individual needs, current conditions, and budget. Adaptations can range from DIY projects easily accomplished by typical homeowners, to more substantial modification of finishes, fixtures, and structure that require design professionals and contractors. The Iowa Program for Assistive Technology at the University of Iowa has published a terrific checklist called the Practical Guide to Universal Home Design. The guide addresses remodeling, building a new home, and buying or renting a home. I encourage you to refer to this as a starting point to plan for the future or to regain full enjoyment and livability of your home. As an example, the image below shows good planning for future accessibility needs. This home is a secondary dwelling, sometimes referred to as a “granny flat” or “in-law flat,” that was built by the property owners for the wife’s parents. Although the ramp was not needed initially, it was included during construction because it is much easier to add such a feature during construction of the house and hardscape. The ramp does not have a handrail and may be too steep to be ADA compliant, but it does not have to be compliant because it is for a private residence. This ramp did however meet the homeowners’ requirements and could be easily outfitted with a handrail when needed. A set of stairs are also included and are located on the far end of the planter, providing a more direct path to the front door for those who can negotiate stairs.

Good planning for the future! Exterior ramp for a secondary housing unit (granny flat), MS|Architecture, Photo: Micah Smith

In subsequent posts I will provide a general overview of universal home design by discussing strategies for remodeling an existing home as well as building a new home. I will use the many available resources including the above guide, the California Building Code, the Americans with Disabilities Act, and my own experience to address basic strategies. Please contact me if you have specific questions or would like assistance improving your home’s accessibility. I can be reached at 805-704-7118 or micah@msmith-arch.com.