“Curious” About Sustainable Design?

October 5, 2009 / no comments


A local group of students from the Boston Architectural College and Tufts University are more than just curious. These students have combined creative efforts, engineering skills, and a shared passion to jump-start a wave of curiosity in others; Team Boston was formed to propose, design, and build an actual solar-powered model home. The Curio House took on its motto, “live curious”, to inspire others to seek out energy-saving, sustainable architecture.


Curio is Team Boston’s entry at the upcoming Solar Decathlon, an internationally recognized biannual competition that works to promote, educate, and foster sustainable innovations in building technology. The competition is sponsored by the Department of Energy and the National Renewable Energy Laboratory. It calls for student groups to build a solar-powered house that will compete in ten categories. The house will be evaluated on its overall energy performance in simulated “daily living” scenarios, on the basis of the quality of its architecture, market viability, engineering, lighting design, communications, indoor comfort, hot water production, appliances, home entertainment, and energy production/consumption through net metering.

The construction site at Tufts University has enjoyed enthusiastic support from other local students, professionals, and community members. Inspired by the students’ bold efforts, and by the innovative nature and challenge of the project, Lam Partners has proudly sponsored Team Boston in their quest for the most energy-efficient solar-powered house at the Solar Decathlon on the National Mall in Washington, D.C.


Over the past couple of months we have had the privilege of getting to know and work with some of the dedicated and high-spirited members of Team Boston to help refine and execute their lighting design goals and strategy. We supported their efforts through computer modeling, mock-up studies, and fixture selection advice, and by arranging generous donations from lighting manufacturers. We’ve collaborated with the team to realize a lighting design with high aspirations for the competition.

Curio takes advantage of many energy-saving, green technologies, such as passive solar design, daylighting, a solar thermal hot water system, and a photovoltaic panel array to generate the home’s electricity. The energy-conscious electric lighting system takes advantage of efficient fluorescent and LED fixtures, occupancy sensors, and dimming to further reduce energy use while enhancing occupant comfort.


The lighting portion of the competition focuses on the quality of a functional, efficient, pleasing lighting design. The lighting concept for the main living space expands on the idea of the house as a central space with a lot of user flexibility. The main ambient light is provided by linear LED fixtures concealed in architectural coves that define the perimeter. There are also several instances of task lighting provided throughout the main living area to accommodate various user needs.

Lighting at the exterior is minimal, with LEDs providing soft, appropriate light levels on the ramp surfaces for wayfinding, and LED downlights to highlight the entries. The exterior is lit exclusively with LED sources to minimize energy consumption. This strategy is used to emphasize the energy savings, as well as to enhance the overall perception of the lighting technologies employed throughout the design.


The house is also engineered in such a way that it can be disassembled, transported, and reassembled for competition. Currently Team Boston is disassembling the house and heading to Washington D.C. to finish construction, compete, inspire curiosity, and exhibit their hard work, from October 8th through the 16th.

The Curio House is a great example of learning, refining, and implementing energy-efficient strategies within daily home life. As part of the continuously evolving “green design” movement, the project defines and proposes viable building solutions for sustainable living, such that the future of the house itself is also evolving.

After a rigorous and exciting cycle of competition in D.C., the house will find a permanent home on Cape Cod as one of the first structures in a new green housing development, where it will be able to live out and expand upon its green foundation and ideals. To follow the progress of Live Curio, throughout the competition and beyond, check out the website at http://www.livecurio.us/.


Image Credits: Team Boston (1, 4, 6); Allison Fisk (2, 5), Glenn Heinmiller / Lam Partners Inc (3)

Why Light It?

September 28, 2009 / no comments


Light pollution and light trespass are hot exterior lighting topics, and they both relate directly to the broader topic of energy conservation. Simple logic tells us that shooting light into the night sky, either directly or inadvertently, is basically a waste of light and energy. The light that escapes above the horizon hits nothing but air, water, and smog. Some of that light is reflected back down as light pollution, that eerie yellow glow that obscures the stars, but none of it is useful – it’s an unutilized byproduct of the artificially illuminated environment.

That’s not a good thing! Sky glow and light trespass have been linked to problems like sleep disorders, migratory bird death, and obstruction of the night sky. Small problems that may seem insignificant? Well, think of it this way: sky glow exposes how much energy and money we pump into the air, and guess who pays for all that extra light – you, the taxpayer! Millions and millions a year, and most of it is powered by fossil fuels.

Can we simply turn off all the exterior lights then? No, unfortunately, the lighting was probably installed in the first place to serve a purpose: the lighting of streets, buildings, parks, and other places that people navigate to at night.

Could we reduce the amount of exterior lighting, though? We can already discern that a lot of lighting is wasted in the sky. Could it also be possible that we’ve intentionally lit that which should not or need not be lit to begin with – that the purpose served was not a legitimate, well-conceived purpose? Absolutely!


Since the invention of the light bulb, we’ve been putting electric lighting EVERYWHERE. We did it because we needed it and wanted it, to see where we were walking and driving (street lighting), to see where we were going (sign lighting), because it looked nice (decorative lighting), to show off our accomplishments (building and bridge lighting), to illuminate nature (tree uplighting), and for security and safety (the former as a police control measure and the latter as a matter of perceived personal well-being).

Now some designers are taking another look at the “why” of design, questioning whether or not we really need all that lighting. Do we need to light a stretch of rural highway when we have headlights on our cars? Do we need to light city centers to 50 lux (5 footcandles for you Imperialists) when 20 will do? It’s not just a question of yes or no, but also of how much.

To take a few of these examples, here are some issues that we should think twice about:

  • Street lighting – do we need to light roadways so much that we can do without headlights entirely? (I’ve seen it – no headlights! Insane!) Perhaps we can use the task-ambient approach here: ambient from very low-level street-based systems, and task from headlights. We’ll still need to pay attention to the vehicular-pedestrian intersections but all that lighting in between could possibly be reduced.
  • Sign lighting – do you really need to light your signs all night long, from the bottom shining up? What if you turned the sign off after midnight, and lit it from above?
  • What about building lighting? Many developers, architects, and designers want to see their projects as the beacon of the neighborhood. Uplights graze the columns, floodlights slam into concrete walls, and twinkly lights adorn the penthouse. Should every building do this, though? Are they entitled to? What if the desire to be the best on the block simply precipitates escalation of building lighting – where does it end? Everyone needs to ask themselves “Should I even light the outside of this building?” That goes for public monuments, too; maybe we should take public money used for lighting public monuments and put it somewhere more useful, like healthcare. How about focusing on the entry and letting the rest go dark at night?
  • How about landscape lighting – why? We light the trees and shrubs only because we can. Yes, it does look pretty, but at what expense? The amount of light the canopy of any particular tree can catch in comparison to what shoots straight into the sky is very little.
  • And finally, lighting for security and safety. This is a very sensitive issue. Police officers, emergency response professionals, and the general public would prefer more light as opposed to less. The popular opinion is that more lighting equals less crime and, while more light will certainly help the police in identifying perpetrators, it doesn’t necessarily create safe environments. There are very well-lit alleys in which all sorts of crimes happen. The statistics have too many variables to pin down an unquestionable correlation. Maybe we should concentrate on good quality lighting that serves these purposes without increasing light levels. Better lighting, not more!


All of these applications are only marginally effective, which supports the position that we simply do not need as much lighting as we have. If a total of three people drive by a building at 3:00 a.m. and see it lit up, is keeping it illuminated all night long worth the collective fifteen seconds of viewing?

Every developer, architect, or designer should question if it’s really worth it. But then, it’s a hard question to ask – who’s to say what qualifies and what doesn’t? Who will speak up and tell someone “no”?

Photo Credits: Liber (1), Ian Plumb (2), Clav (3)

Daylighting Through Building Weight Loss: Thin Your Way to Sustainability

August 24, 2009 / no comments


Ever been in a building so big that you can’t see a window or what’s going on outside?

A lot of modern buildings are so big, fat, and wide that you can get lost in their bowels and, unfortunately, those depths can’t function without the help of electrical or mechanical systems. They’re on life support, so reliant that a venture into the interior spaces is impossible without power. We’ve been designing caves!

Long gone are the days when architects and master builders had to rely on natural ventilation and daylight to make their buildings inhabitable without a torch. There may be a light at the end of the cave, though. Recent sustainability efforts like LEED, among others, are seeking to reintroduce some of these design elements for one reason or another, but they’re always optional, and the guidelines lack teeth.

Until recently, it has been cheaper to pay for electricity and gas over time than to pay more up front for a building to use less energy. That’s going to change soon. President Obama’s plans to increase energy efficiency and reduce fossil fuel consumption over the next twenty years is very ambitious. At first glance, it almost seems impossible to get to zero percent net energy use by 2030. Some of those goals can be met with renewable energy sources, onsite or off, but the rest of the savings will need to be made up by simply cutting the energy we use. How? Can you look around your office and pick out what you can live without?

In the past, would-be building owners sought the best buildings to suit their needs for the least money. But are building designs and costs truly independent of sustainability and conservation factors? It usually costs more, however slightly, to build something that’s more environmentally responsible, whether for better-quality materials or for the design expertise to put it all together. So, what doesn’t show up as a cost of building instead takes on a long-term cost on people, resources, and the environment. Some of that deferred cost has already come back around, hence the sustainability movement.

Now, economically and geometrically, the cheapest typical building shape that best utilizes open space is one that looks like a pancake or cube. Any other shape and you could end up spending more on the skin, structure, and support systems. The core of thinner buildings takes up more of the floor plate per floor and ultimately, less space is available per dollar spent. Owners also like to maximize the building footprints on their land, oozing to the edges of the plot and thickening the building. So, the tendency and enticement to ‘fatten up’ a building persists.

Why, then, do we want thinner?

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One problem with the fat design is that there is no opportunity for natural airflow. Interior walls and the sheer breadth of the floor plate are not conducive to promoting airflow from one outer wall to another. Mechanical ventilation is introduced without any further consideration, and it takes on the role of breathing for the building. Mechanical ventilation = energy use.

Daylight, too, is proportional to distance from windows (skylights are great but only for the top floor). Without daylight delivery integrated into the façade design, the effective daylight zone is about twelve to fifteen feet into a space. With lightshelves or other daylight redirection devices, you can potentially get up to thirty feet into the space. So generally, a building any wider than sixty feet can’t fully take advantage of natural lighting. No available daylight = electric light = energy use.

Building energy use varies by building type and location, but the four major energy sponges are heating, cooling, lighting, and plug loads. Let’s assume that we won’t be giving up refrigerators or computers anytime soon, so our plug loads are here to stay. That leaves the big three – heating, cooling, and lighting – which we have the least control over as occupants, and the most impact on as designers. By designing our buildings to passively take advantage of heat, light, and air from outside, we can rely less on the electricity-based systems we use to force life support into the centers of our caves.

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Ask yourself: “Will my building be able to function if we run out of, or are not allowed to use, electricity or gas?” The answer should be yes!

Are there any other reasons for thinning up our buildings for natural ventilation and daylight? Three great ones: these energy sources are free, readily available, and are products of the environment instead of an impact against it. As lighting designers, we can confidently say that the most energy-efficient electric lighting is the kind that is turned off.

Photo Credits: Dagbrown (1); Global Jet (2); Mark Sebastian (3)

Heliodon 4.0

August 10, 2009 / no comments

In an era when computer speed and software capabilities are constantly improving, one might wonder why any lighting design firm would bother with physical model-testing for daylight analysis anymore. There are many different types of software available today that can be useful for studying daylight in architectural spaces, but there are still compelling reasons why studies performed by traditional methods will never be completely replaced by computers.

The cornerstone of these methods is a multi-axis device known as a heliodon. A scale model is first secured to the table, oriented correctly north-to-south, and then the table is angled to match the latitude of the real building’s location on earth. A solar sundial is positioned next to the model to identify time of day and time of year.

Rotating and locking one axis of rotation then establishes time of year, while rotating the angled table recreates the changing time of day. Once these variables are set, one can immediately see daylight interacting accurately with the model any time of day, any time of year, anywhere on earth.

The newest heliodon at Lam Partners is a testament to the belief that physical model-testing continues to be indispensable in evaluating daylight. Easy video integration, fast modifications to the model, perfect rendering of materials, and a comprehensible interface are all reasons why we decided that upgrading our heliodon was worthwhile, and this fourth-generation model incorporates new design features gleaned from 35 years of daylight analysis experience.


The primary feature is the motorized table that allows for precise rotation, used in conjunction with a digital video camera. A heliodon is able to quickly cycle through sunrise to sunset, so smooth rotation at a consistent speed is critical for high-quality video output.

Another feature is a wide, stable, and adjustable base platform that is removable and can be field-leveled for the most accurate results. Part of the overall design objective was to make the entire heliodon easily broken down and portable, with three easily reassembled components that all use the same size bolt. All necessary tools are stored neatly within the frame and easily accessed.


The improved precision of the new heliodon required a sundial that was equally precise. We designed a new one and had it CNC machined from solid aluminum, like the heliodon (yes, the chips were all recycled!). The new construction features an adjustable and lockable latitude angle, as well as a removable and replaceable gnomon that can be safely stored within to prevent damage. A polar sundial design was then laser-etched onto the front for durability.

Together, the new heliodon and sundial provide a level of exactitude never before realized in earlier designs. After the initial set-up, an architectural model can easily run through an entire year’s worth of sun-angles in barely an hour on the heliodon. Since sunlight works the same at any scale, measured footcandle levels inside the model, when factored to account for local latitude and season, are accurate and reliable.

This breadth of valuable information takes far longer to gather using computer software which usually lacks the intuitive feel and quick adjustments that physical modeling offers, and most daylighting software continues to struggle in accurately representing complex materials and textures or multiple reflections.

So, while Lam Partners certainly does use software for some aspects of daylight study such as basic sun-angle geometry, the qualitative advantages inherent to heliodon analysis make it an extremely useful tool for daylight-intensive projects.


Photo Credits: Anna Baranczak / Lam Partners Inc (1, 4), Justin Brown / Lam Partners Inc (2, 3)

Fight the Power!

July 20, 2009 / no comments


Compliance with energy codes has become a regular part of the design process for lighting designers in recent years. Prior to the release of the 2004 version of the ASHRAE/IES 90.1 standard for energy codes, it was easy to design lighting without worrying about bumping into code limits. This was because codes had not yet caught up with energy-efficient technologies and current design practices. The ASHRAE 2004 standard was significantly more stringent in its limits on the total amount of connected lighting load allowed. It is still possible to produce quality lighting design under these limits, but much of the headroom went away. Frankly, you can’t be sloppy anymore, and this is a good thing. So, less energy use, more code compliance work for lighting designers – happy ending, right? Well, maybe.

Let’s look at the structure of U.S. energy codes as they apply to lighting. They aren’t really energy codes, they are more like power codes. The main way that U.S. energy codes regulate lighting is by limiting the amount of power (watts) that your lighting system can use. This is done by giving you allowances for maximum lighting power density (LPD), measured in watts per square foot, for various building or space types. In other words, the amount of power you can draw with every light in the building turned on at full output – but it is the rare building that has every light turned on 24/7.

Energy = Power x Time, so an energy code needs to take power (watts) and time into consideration. This is why we pay for electrical energy by the kilowatt-hour (energy), not by just the total wattage of all the devices connected to the meter (power). To be fair, current energy codes do have provisions that address the time variable of the equation – but they only do it by requiring automatic controls to shut off the lights when not needed. There is no quantification or metric of what those controls get you in energy use reduction. A building with lights on 20 hours per day is treated the same by code as a building with lights on 10 hours per day. A building with the most rudimentary code-minimum controls is seen as identical to a building with sophisticated occupant-sensing and daylight-responsive controls.

We can see why lighting power as the metric for building lighting energy-efficiency is deficient, but is this a big problem? Yes, and here is why: energy use of our buildings must be reduced radically – the push to do that by improving the performance of envelope, HVAC, and lighting is strong and growing stronger, and rightfully so. For example, the energy bill working its way through Congress, at 1,000-plus pages, contains a section to institute energy codes enforceable at the Federal level with a target of 55% energy reduction (over the 2004 code baseline) by 2018, and 75% by 2030. Serious stuff! So when looking at lighting, the obvious thing is to just keep reducing the lighting power allowances, right? Wrong! The use of more efficient lamp and fixture technologies alone can’t achieve these targets. If we just keep pushing down power allowances, lighting quality will suffer and we will find ourselves sitting in dark rooms or bland white rooms lighted with bare, glary light bulbs. To truly reduce lighting energy use we need to figure out a way to write a code that actually regulates lighting energy, not lighting power.

Photo Credit: Isaac Bowen

What’s “Efficient”?

July 13, 2009 / no comments


Today we’re barraged by claims of “efficient lighting” or criticisms of “inefficient lighting”, but what does that actually mean, or what should we actually be concerned about as designers?

In casual terms, we think of “efficient” lighting as using less energy to produce a given amount of light, or as producing more light for a given amount of energy. Technically, the term used to relate visible light produced to overall power consumed is “efficacy”. This is typically expressed as the ratio of visible light to electric power, or lumens per watt. But for practical purposes, efficiency means providing the useful light we seek for as little energy consumption as possible. Useless or wasted light doesn’t count. Or even more importantly, it should mean satisfying our visual needs using as little energy as possible. And that can’t be measured with a light meter.

With today’s emphasis on energy-efficiency, too often evaluating “efficiency” based strictly on light meter readings (or on calculated predicted meter readings) results in visual environments of poor quality. So the key question we need to ask about efficiency is: “efficient at what?” A bare light bulb hanging in your living room could be very efficient at registering on a light meter, but very inefficient at creating a comfortable visual environment.

If we do limit ourselves to what can be measured with a meter, for architectural lighting there are really four components to efficiency:

Lamp efficacy: how much visible light is our lamp (“bulb”) producing for each watt of electricity?

Control gear efficiency: with the exception of incandescent (including halogen), all modern light sources require some electrical components to get the lamp started and to provide the proper operating voltage and current. These ballasts, transformers, and LED drivers consume energy, sometimes a lot of it – they can use 10% or more as much energy as the lamp they serve. So we need to include this energy consumption in the overall lighting efficiency evaluation.

Luminaire efficiency: rarely does all the light from a lamp manage to get out of its light fixture. There are almost always shields, reflectors, lenses, etc. to shape and baffle the light output, and these block some of the light from escaping. Luminaire efficiency can range widely: for a good linear fluorescent indirect-direct pendant it might be over 90%; for a good compact fluorescent downlight it hovers only around 50%. (One of the advantages of LEDs is that, although their efficacy is not particularly high, because LED light output is intrinsically directional, luminaire efficiencies can be higher for direct, controlled beam applications).

Utilization: related to the antiquated “CU”, or coefficient of utilization, this is basically the fraction of light coming out of a luminaire which actually ends up doing something useful – lighting a surface we want to light. A good (or rather, bad) example is the typical dropped-lens cobra-head streetlight. What we want to light is the roadway and maybe the surrounding area or sidewalks. But, as anyone who has ever looked out of an airplane window knows, an awful lot of the light from cobra-heads goes right into the sky. This isn’t useful (in fact the opposite), so it doesn’t count in the “utilization” coefficient.

So we need to multiply all these four factors together to get even a simple numerical evaluation of a lighting system’s “efficiency”. There’s also a fifth, very important factor affecting energy use: controls – the most efficient light can be the one that’s turned off when it’s not needed.

But lastly and very importantly, we need to consider whether a good design can achieve an equally good, or better, visual environment while registering “less” on the light meter. There is no question that this is possible – it happens all the time. A study by the GSA of recently completed federal courtrooms (see link below) found that measured light levels had little to do with actual user satisfaction with the lighting. As another example, an environment with a substantial indirect lighting component can have lower measured light levels while actually providing better visibility and a greater sense of brightness and comfortable seeing. So let’s design for true efficiency: satisfaction per watt.


Photo Credit: SwamiStream

The Rise of DALI – again?

June 22, 2009 / no comments

More often than not, if you ask a lighting designer or engineer what DALI is and if they specify it, you’ll get a puzzled look or a chuckle. Some designers are dipping their toes in the pond, but most are waiting to see what the other guys are doing, not wanting to be the first for fear of getting burned on an unproven technology. The truth is, however, that while the U.S. has been plodding along with good old switching relays, 0-10V, and line-voltage dimming, the European design community has already taken lighting control into the digital age and embraced DALI as the preeminent, universal lighting control language.

While those traditional technologies are tried and true, complacency does not constitute a reason to ignore a proven system which has the potential to save time, money, and energy, while increasing beneficial functionality. Here are a few points that examine why DALI has potential and why we aren’t using it enough.

First though, we need to know what exactly DALI is. DALI (not Salvador Dalí) stands for “Digital Addressable Lighting Interface”, and is basically the computer language that devices send and respond to, kind of like Morse code for lighting. The DALI control signals are transmitted over two low-voltage wires that connect to each DALI ballast or relay, each of which has a unique address. Control commands are sent out over the wires to tell individual devices or groups of devices to turn on and off, dim up and down, etc. The devices even have the ability to report back to the controller indicating a lamp failure or how much power they are using. This kind of send-and-receive communication is analogous to a teacher (controller) and classroom full of students (ballasts and relays). The teacher gives instructions to the students (which they obediently obey), and each can answer questions when called on.

What does DALI have that your current controls systems don’t have?

DALI systems can use up to 60% less branch wiring than traditional controls

That’s a strong assertion, but if you lay out the wiring for a traditional system and measure it, for any typical room you would see that by the time those switch legs go down and back up the wall and then out to each controlled zone you have quite a bit of wire. Don’t forget to consider the conduit – lots of metal! Now, if you lay out the same space with a DALI system, you simply don’t have all those switch legs to contend with. The branch circuit flies into the room from the adjacent space, hits each light fixture or addressable relay, and continues on to the next room. All switching and dimming is done in the ceiling at each fixture, not in a wallbox or remote cabinet. While there is some control wiring that connects all the controlled fixtures into a loop, that wiring can be Class 2, run without conduit, (or Class 1 that runs in the same conduit – still cost less than switch legs) and results in much less material, labor, and cost.

DALI wiring diagram

DALI is based on an open protocol

Using an open protocol means that anyone can develop their own DALI devices, ballasts, relays, sensors, etc. The programming language is freely available to anyone that wants it.

That also means that it has the potential to be a universal language for the lighting industry (as has happened already in the EU), so Brand X DALI light fixtures will work with Brand Y DALI control systems. You don’t need to worry about compatibility and which type of dimmer to use anymore.

DALI is easy to specify

Whether the lighting designer or engineer does it, someone has to figure out which traditional dimming ballast or transformer to use with which traditional dimmer. With DALI, it’s simply DALI – DALI ballasts with DALI controllers. Most of the major ballast and gear manufacturers have DALI ballasts already available, and their product offerings continue to expand. Even better, most ballasts, DALI or otherwise, are now universal voltage – you don’t even need to coordinate that!

The proliferation of DALI will also allow for three-name ballast specifications again, unlike the forced specification of a proprietary technology caused by no two systems being alike.

DALI is easy to install

A light fixture gets power (120 or 277 volts – it doesn’t matter as far as the control is concerned) and control wires – that’s it. The rest is in the programming. The control wires are polarity-free, so it’s virtually impossible to wire a fixture incorrectly, unless you forget to. Once contractors understand how easy the installation really is, and they get past the “new technology” hesitation, they should be jumping for such an easy system. Some already have.


So why hasn’t the U.S. embraced this technology yet? Some of the reasons are more complex than others, but there are many possibilities:

Lack of specifier demand

This is simply a chicken-or-the-egg question. If specifiers don’t know about it or don’t understand it, how would they know to ask for it?

The perceived complexity of digital communication and control is something that might be hard for specifiers to wrap their heads around. It’s certainly a lot different from switching and dimming line voltage we’ve been using for the past 40 years. Since there are few manufacturers with front end systems, thus far, education has been lax.

Manufacturer hesitation

For the same reason that specifiers are hesitant to specify it before the competition weathers the “new technology” first, manufacturers are wary of investing in the development of a new system that is so different from what they already offer. They want someone else to do it first to see if it takes off or flops.

There are a few manufacturers that have come up with quasi-digitally-based systems but they’re mostly proprietary, operate in different ways (i.e. cannot be listed as equals), and usually end up converting a digital signal to analog. Unless these systems permeate throughout the industry, their fate will be to persist as a minority, or they will cease to exist.

Sometimes DALI is even discredited as “slow”, “old”, and “expensive”, rejected for specific business interests and investments in competing technologies. A lot of time and money has gone into developing all those other control systems, and to simply adopt DALI, the universal open protocol, would almost certainly cut into profit margins. This may be the single biggest hesitation factor in the U.S.

So what’s next for DALI? Will it ever fully take off in the U.S.? There certainly is vast potential for any manufacturer that wants to take up the technology. It makes sense from so many angles, and if we could just get everyone to agree to adopt it we’d really have something, but that’s a bit like herding cats – good luck!

Photos credit: Matt Latchford / Lam Partners Inc

Lite-Brite ™

June 14, 2009 / no comments

Remember when you would assemble those little translucent pegs in any configuration possible to create a luminous image of your wildest imagination? There were no limits to how the pieces could be arranged within the board boundary; each glowing pixel of plastic contributed to the overall illumination from an assembled light source.


Some manufacturers are starting to realize this same freedom as they research and develop new lighting hardware utilizing LEDs. Taking a new technology or light source and inserting it into an existing fixture design doesn’t take advantage of the technology, though, and this is where many new LED products fall short. The fixture must exploit the benefits specific to the new light source and utilize them creatively to push the boundaries of what can be achieved with these assembled light sources.
There are still heat issues, light color, lamp efficacy, and lamp life issues that need to be dealt with and carefully understood. Not all claims are accurate, however, there’s no question that these factors are rapidly improving and the quality lighting manufacturers are developing new and exciting products.

Where LEDs, within architectural lighting applications, can really excel is in the optical design of the fixture. No longer do we need to bend sheet metal around a lamp to form a reflector that redirects the light in a particular direction. Clever LED configurations and mini-optical lenses can be and are being designed to precisely control light distribution. This Lite-Brite™ approach allows the fixture design, both optically and aesthetically, to develop without being constrained by traditional forms.


Manufacturers of parking garage, roadway, and some exterior area light fixtures are beginning to thoughtfully explore possible LED configurations and tailor the luminous distribution in ways that begin to make LEDs a viable replacement for some lamp sources. Extremely wide and precise fixture distributions can be achieved, creating excellent uniformity ratios. While lamp efficacies (lumens per watt) of LEDs are not yet outperforming standard HID and linear fluorescent sources, it is possible to design LED fixtures with a higher overall system efficacy. Again, this is achieved by the mini-optic on each diode or the precise configuration of the LEDs themselves, rather than a bent metal reflector around a bare lamp.


Don’t be fooled; I haven’t jumped on board the LED bandwagon entirely. One of the biggest downsides of many new LED fixtures is the increased glare and fixture brightness. Often, the wide distribution and increased uniformity is achieved at the cost of higher angle glare and less cut-off to the lamp source. With the lamp source right at the fixture aperture and the optics designed to maximize the lateral distribution, some LED fixtures are so bright that their negative impact on the nighttime visual environment is far greater than the potential benefits of the new technology.


There is a long way to go, and the designed balance between optical performance, lamp source technology, and fixture aesthetics is no easy goal to achieve. It is very clear that the endless creativity inspired by those assembled toys of luminosity point to an exciting time in fixture design and architectural lighting applications. The possibilities are limitless, so explore the design boundaries without introducing bright light!
Photo Credits: Crystl (1), HessAmerica (2), Beta Lighting (3), Jamie Perry / Lam Partners Inc (4)

Daylighting Reduces Heat Gain – Pantheon Redesign?

June 14, 2009 / no comments

 In our June Photo of the Month article, we talked about the daylighting in the Pantheon. Let’s do some numbers just for fun: on a partly-cloudy March day in the mid-afternoon there will be about 1.2 million lumens streaming through the Pantheon’s 700-square-foot oculus. The interior light levels are fine. If we tried to equal that with large metal-halide indirect floodlights, it would take about 15,000 watts. The heat energy in the daylight will be about 10,000 watts. So if heat gain is a negative, the daylight is winning on that count.

But we can make it even better: let’s renovate the Pantheon, so we have glazing, not an open aperture. The right glass can help. First, we’d need to increase the aperture area to compensate for the light transmission of the glass. So we increase the Pantheon aperture to 1,000 square feet to make up for a light transmission of 70%. Now we still have the original amount of visible light, but what about heat? Using a high-quality low-E insulating glass, the heat gain per square foot would be reduced to about 35% of what the same aperture would admit with no glass. So despite the increased aperture area we actually have only half the heat gain of the original open oculus, with the same amount of admitted daylight.

Let’s compare that to the electric lighting equivalent. All of the daylight is going to eventually end up as heat in the space, and so will the electric light and the electricity used to produce it. So with the new glazing our daylight is adding 5,000 watts of heat gain. The equivalent metal-halide system is adding 15,000 watts. So the daylighting is now creating only about one-third as much heat gain as the electric lighting that would achieve the same light level.

So that’s a big win for the daylight, right? Maybe. It’s a win only if we assume that the daylight light levels and the electric light levels are the same, and that’s tricky. Clearly, if the daylight levels are higher there will be more heat gain; if they’re three times higher the daylight will produce the same heat gain as the electric system. This is not as unlikely as it may sound. It’s easy to design an electric lighting system that maintains virtually the same desired light level all the time – it’s not at all easy to do that with a daylighting system.


For the Pantheon, what happens on a nice sunny May afternoon around 2:00? Now we have well over 5 million lumens coming in through the oculus, and even with the new glass the heat energy in the daylight will be about 22,000 watts, or about 75,000 BTU per hour. But the electric lighting system would still be plugging along at the same 15,000 watts. Sure, the daylight level is now higher than the electric light level, but we don’t need that extra light, and now the daylight is producing more heat gain than the electric lighting would. And that means we’re going to increase the amount of energy we have to use to air-condition that heat away (did I mention we’re adding air conditioning, too?). And by June the problem will be even worse.

This illustrates one of the important challenges of designing daylighting: maintaining reasonably consistent light levels at different times of day and different times of year (and also under different weather conditions). There is a related design challenge: maintaining consistent light levels at a given time but in different parts of the space. Because the Pantheon aperture is at the center and high above the floor, light levels at the floor will generally be very uniform (although occasionally on mid-days in summer direct sun will hit the floor, and all bets are off).

But in multistory buildings the daylight often has to enter from the sides, and we don’t usually have 142-foot-high ceilings, so daylight levels near the windows tend to be much higher than those farther away. The issue is the same for both challenges: if we design for an adequate daylight level for less-than-favorable conditions or locations, we can end up with much higher than needed daylight levels for the favorable conditions or locations.

There is also a tendency to simply overdesign daylight levels under all conditions. Our Pantheon example had a daylight aperture of only about 4.5% of floor area: a glass curtain-wall building could easily have a ratio of 40%. Without extensive shading and low-transmission glass, that is very likely to result in daylight levels much higher than needed. And those higher levels bring higher heat gain. They can also be visually uncomfortable, but that’s another subject.

Photo Credits: Irene (2), OliverN5 (3)

Making the Sausage

June 14, 2009 / no comments


You’ve heard the saying, “There are two things you will never wish to watch: the making of sausage and the making of legislation.” As the new chair of the Energy and Sustainability Committee of the International Association of Lighting Designers (IALD), I’ve been getting a glimpse into the kitchen.

Why, you might ask, would a Lighting Designer care about the making of legislation? Energy codes, light pollution ordinances, LEED, green building codes, Federal energy efficiency legislation, Department of Energy rulemaking, and on and on. Get the picture? All of these things affect our work as lighting designers, directly or indirectly.

Lighting Designers have a responsibility, and an obligation, to minimize the negative environmental impact of their design decisions. Mostly, this means energy! energy! energy! Making lighting more energy-efficient is the easy part. The hard part is doing it without destroying the quality of the visual environment – this is what we do.

So, back to the sausage. We get involved with the development of energy codes and standards and legislation to make them the best they can be. Don’t get me wrong, this isn’t about resisting or trying to make standards more lenient. This is about maximizing real energy savings while simultaneously maximizing lighting quality – no simple task. Too often, standards have been developed by people who do not understand this balancing act. A belief that simply limiting the available watts or setting efficiency standards on equipment is enough can lead to unintended consequences, such as the obsolescing of unique equipment, or increased glare and light pollution.

The energy bill winding its way through Congress has an outdoor lighting energy efficiency provision that is being negotiated by lighting manufacturers and environmental groups. Our committee has been following this process and making ourselves heard (see IALD position statement below). We provide an independent voice that understands how to reduce lighting energy use of the total lighting system and how to create quality luminous environments. You need to understand this if you are going to write an effective standard, right? This is what motivates me to watch, and sometimes help, make the sausage.

Photo Credit: Stephen M. Lee