The reason for daylighting in buildings is to save energy, and so the value (“payback”) of that daylighting can be calculated by predicting and pricing the amount of energy saved. That’s a common line of thought which is easy to slip into, but it’s dead wrong.

Let’s look at a simple example of a new office building. A typical office worker’s space, including adjoining corridor, is about 110 square feet. Under today’s codes, we’re allowed 100 watts maximum to light that space. If it’s lighted 10 hours per day, 5 days per week, 52 weeks per year, that lighting will use 260 kilowatt-hours per year. At a high-end cost of $0.20 per kWh, that’s 52 bucks for electricity to light that space for a year. Let’s add another 30% for extra cooling cost due to that electricity, and we’ve got almost 68 bucks.

If our worker is the median American clerical worker, according to the US Bureau of Labor Statistics, his salary rate is about $14.40 per hour. Throw in 25% for statutory fringe benefits, and he’s costing his employer 18 bucks per hour.

So let’s say we have a wonderful daylighting design which uses absolutely no electricity to light our worker’s space. That 68 bucks per year equals less than four hours of his salary. That’s right: four hours.

If we have a wonderful daylighting design which improves their productivity by 1%, that saves their employer 375 dollars per year. A productivity improvement of just 1% creates a “payback” five-and-a-half times greater than the value of saving all of their lighting electricity. Run those numbers for a more highly-paid professional, legal, or scientific worker, and the productivity value will be much higher still.

To put it another way, if we calculate the payback of daylighting based only on electricity, we’re grossly underestimating the real payback; we’re shortchanging the daylighting. And that will lead to incorrect design decisions.

Some sophisticated building owners and managers know this. Savvy retailers know that their sales will go up with daylighting. Knowledgeable educators realize that the performance of students in daylighted classrooms will improve. Daylighting produces known health benefits.

We tend to think of these benefits as intangible, but they actually represent large numbers of tangible dollars on the bottom line. Like productivity, these factors aren’t intangible, they’re just hard to quantify.

By the way, the same calculation applies to good electric lighting as well: it may save a few dollars in electricity each year, but its value is vastly greater than that.

Photo Credit: ©Anton Grassl/Esto

While LED technology has been the darling of fixture designers, linear fluorescent lamp and ballast manufacturers have been continuing to develop a diverse range of products that round out a comprehensive toolbox for sustainable design. In addition to providing smooth light output, high color rendering, a variety of color temperature options, and good value pricing, linear fluorescent lamp-life has slowly been increasing, bringing it in line with the rated life claims of LED systems.

Are LEDS really the best option for a light source with an extended rated life? Rated life of white light LED systems currently hovers around 50,000 hours. Of course, that exciting number needs to have IES standard LM-79-2008 and/or LM-80-2008 testing to give it credibility – and LED life is dependent on thermal management, meaning that long life can be compromised by excessive heat being trapped at the diodes.

Meanwhile, lamp manufacturers are introducing new T5 and T8 fluorescent lamps with similarly extended lifespans. Newer T8 lamps on instant-start ballasts can last as long as LEDs, or, with program-start ballasts, even 55,000 hours.

However, one thing the LED has done for fluorescent technology is reinforce the importance of the entire lighting system, in this case bringing the combination of lamp, ballast, and controls to the forefront. In linear fluorescent fixtures, it is the total package – lamp, ballast, and system efficiency – that counts. A common myth persists that T5 and T5HO lamps are more efficient than T8 because they’re a newer format, but in reality T8 lamps win the race, consistently offering better efficacy (light output, or lumens per watt).

Standard-output 28-watt T5 lamps produce around 2,900 lumens with a connected load of 34 watts (85 lumens per watt); high-output 54-watt T5HO lamps produce 5,000 lumens for 62 watts (81 lumens per watt). In contrast, a 32-watt T8 lamp with 3100 lumens on a high-efficiency ballast (0.88 ballast factor ballast) offers 28 watts – 97 lumens per watt.

T5 and T5HO are still priced at two to three times the cost of T8 lamps. The real potential of T5 and T5HO lamps is that their smaller diameter allows better optical control, resulting in better reflector design, smaller fixture profiles using less material, and the opportunity for more efficient photometric performance.

To use T8 lamps successfully, there are lots of options to keep in mind. Four-foot T8 lamps come in many varieties: F32T8, F28T8, and F25T8 which allows for the design of tailored systems, with light levels and power densities to suit a project’s needs. But, should you need a controllable system that requires dimming, then the F32T8 in most cases is the only lamp that dimming ballasts want to work with (although ballast manufacturers are working on products to fill this gap).

Take charge and specify ballasts to write a better energy story. High-efficiency ballasts can result in higher system efficacy, using less power, but they need to be identified in fixture specifications in order to be provided. Otherwise you will end up with generic electronic ballasts (GEB) at the manufacturer’s discretion. High-efficiency, high-ballast-factor ballasts can over-drive T8 lamps to produce more light when needed, within allowable power-density criteria, without compromising rated lamp-life. This option is helpful in situations where one lamp is not quite enough light, but a project can’t allow the power density of adding a second lamp. When one lamp is too much, low-ballast-factor ballasts with high-efficacy lamps can provide a cost-effective continuous glowing cove, such as those used at the University of Chicago’s Gordon Center for Integrative Science, where a glow was desired to create a lantern-like effect.

High/low ballasts offer cost-effective switching options for meeting code requirements when the budget can’t afford a dimming system. However, care should be taken to determine if the 50% power level of this type of ballast delivers light levels appropriate for the space – otherwise the lights will always be switched to full output by the users.

Dimming ballasts save energy, and have been finding their way onto more mainstream projects (to support daylight-responsive dimming, or lower light levels during classroom projection), but the reality is that at full power, dimmable ballasts consume more energy than a standard high-efficiency ballast. There is a campaign for code criteria to recognize that power consumption over time is a more accurate way to document power and energy savings than connected load. Until that happens, dimmed fluorescent lamps use little energy, but in power-density calculations, they still exact a premium in terms of connected load.

Photo Credits: Arria Belli (tortoise), Polandeze (hare), Anton Grassl/Esto (project)

Well, I just made it up – just now. It’s not a new concept by any means; I’m applying it to lighting, although I suppose you could apply it to just about anything. It’s about efficiency and utility: how much of something do you get versus how much you lose, and is it worth it?

More specifically, with lighting, how much light do you get out of a fixture from all the light generated inside the fixture? For example, let’s say that you have a downlight that has a lamp in it (it doesn’t matter what lamp for the sake of this argument, but let’s just say that it’s an efficient one). The fixture efficiency of that downlight is the ratio of how much light exits the fixture (ideally in the direction that you want it to) to how much light that lamp can produce overall. Most downlights have fixture efficiencies somewhere around 50%, meaning half of that light is lost inside the ceiling.

So how does this become a rule? The rule is that you should use more fixtures that have greater than 50% fixture efficiency than those that have less than 50% efficiency – otherwise you’re wasting more light than you’re using. This may seem fairly obvious when you consider it, but I doubt that you look at it this way when creating a design. I’m describing this theory as a rule of thumb – and giving it a name to remember it by – to put a subconscious bell in your mind, intended to start ringing when you’re designing.

Seems straightforward, right? Not exactly. There are a ton of light fixtures out there that piddle around in the 30% range, barely letting any light out at all. They’ve been evolving over the years and include a lot of very sleek and narrow fixtures that have high aesthetic appeal, or have a very specific purpose, like a tight beam of light from a tiny hole in the ceiling. Efficiency hasn’t always been a big part of that evolution, and while some of those fixtures do have a time and place, they are used all too frequently. Have you ever specified or used one of those two-inch-wide light fixtures in your designs? Lots of manufacturers have them – nothing new there. But have you looked at their efficiency? It’s often less than 50%. That means that more than half of that energy is wasted.

In the bigger building-wide picture too, any energy that doesn’t get out is not only wasted, but also turned into heat, which needs to be removed by air conditioning, which uses even more energy. So the wasted energy exceeds usable energy even further.

Of course, if a fixture passes 50% efficiency, that doesn’t mean you should stop there. If there is another fixture 20% more efficient, which produces quality light in the way you want it to, all the better. Every little watt counts.

How, then, do we measure worth? It’s subjective, and hard to precisely define. Ask yourself what you want to do and what tools you can use to do it. If your goal is to light a private office, and you have a choice between that two-inch-wide slot or a four-inch-wide version with twice the efficiency, I would argue that two out of three of your goals are met by using the wider version: lighting the space, energy efficiency, but maybe not as sexy. If you choose the narrower fixture, can you say the same? Maybe that wider fixture is starting to look sexier now?

There will always be some applications that really do have very specific solutions, and that’s why this isn’t a hard-and-fast rule. It’s merely a tipping of the scales – worse or better, overall.

Take this example: two identical private offices with the same design goals – illuminate to 30 footcandles average, and use less than one watt per square foot. One office is lit with 60% efficient fixtures; the other with 30% efficient fixtures. Both offices achieve almost the same light levels, and both meet the power code requirement. The one that uses the less efficient fixture uses twice as much power, and twice as many fixtures, to do the same thing. Then there’s also the added cost of lamps, ballasts, installation, and maintenance.

Now, one may ask: ‘who cares how efficient it is if it does the job and meets code?’ The U.S. Department of Energy does! Energy usage in buildings will only continue to be restricted, so we simply have to be more efficient in order to continue to meet code requirements. And, it’s the difference of just a few local kWh in your building; if you assume that every building in the country has some waste in them like yours, and add that all up, it could mean that whole power plants are operating just to satisfy that waste. It makes that much of a difference.

So, my plea to the design community is that if less than half the energy that goes into a fixture gets out of it in it’s intended form, then it behaves more like a trap than a delivery method – so use it sparingly. Some may argue that you can’t use many inefficient fixtures anyway because the codes are already too strict – otherwise you’d end up with under-illuminated spaces. But most of us are more reactionary, and only cut or change something if we find out that we’re over code-allowed watts, essentially using all the available energy we can. Try to be proactive and make the design more efficient than not from the outset. Let’s not build the least energy-efficient buildings the law allows – we can do better.

Photo Credit: Sleeping Sun

But is the current energy code the best way to save energy? Is lowering the allowable maximum connected load for lighting even enough to get us the savings we need to meet the national energy goals of 2030? Probably not.

Over the past decade, the allowable lighting power densities (LPD) have been lowered time and time again, sometimes logically, and other times less so. The mantra has been to increase energy savings by lowering the amount of connected electric lighting load – end users are then free to turn that connected load on and off at any time. The problem with this method is that it doesn’t account for real usage. How energy-efficient is a low-power lighting solution if it stays on all the time?

For example, take a typical ten-foot-square office space with 1.0 watt per square foot allowable LPD. You can use up to 100 watts in that particular office. Now, if you leave that office light on for 24 hours (i.e. you forgot to hit the switch on the way out), you’d have 240 watt-hours (that’s 0.24kW-h on your energy meter). But not everyone forgets to turn off their lights, so that scenario is the worst case.

A lighting design can thus easily be checked against the code while still on paper, and this is pretty straightforward, but it doesn’t take into account how the end user will use that lighting. The lighting is designed for a maximum load at a single point in time (power), but is then measured as energy (power x time) – there’s a disconnect between the design and the application. The kicker is that there is no simple real-world method to check or enforce codes once a space is occupied. Owners are free to burn the midnight electrons and no one will say boo about it.

Now take that same office space but, instead of designing only for power allowances, you design it for power and time. What if you make an allowance for the lighting to be on for only 12 hours per day (a standard assumption for all but the craziest workaholic American). You could use the same 100 watts but the total energy used is now half that of the worst-case scenario. What if that same office has windows and daylight dimming, and the lighting is only on for 4 hours each day, just 40 watt-hours – we just went from half to one-sixth of the energy used!

So how do we predict how occupants will use lighting, and how can we make sure they then keep using it as intended? Mandates and accountability. As much as we’d like to assume that everyone will hit the light switch on the way out, that’s a bit too much wishful thinking. Cost is no deterrent, either – major corporations have money they seem happy to spend, and with the cost of energy artificially low in this country, there’s not much incentive.

There’s a growing movement in the code world to actually factor anticipated duration of use into the equation, measuring compliance in kilowatt-hours rather than just watts. We’ll always need to reference watts in our design process, but eventually we’ll have squeezed out all the watts we can, and it still won’t be enough. Adding time into the equation doesn’t immediately guarantee energy savings, but it does put it in terms that we can identify, relate to, track, and react to. It’s time to think more about energy, and less about power.

Photo Credit: Steve Ryan

Recently a lighting company came into our office to show us their new LED fixture. I prepared myself for the usual spiel: tight quality binning, a high-performance heat sink, ELV dimming option. However, this particular fixture had been designed in a way that we haven’t seen from many other companies: the entire fixture, an LED cove/grazer product, was actually designed along sustainable manufacturing principles. Its connected load is more energy-efficient than that of its fluorescent counterparts (finally), but more impressively, the materials used to construct it had been thought through in a way few other products seem to manage.

The housing was not anodized aluminum, the standard seen in LED fixtures required for heat dissipation, but a zinc-based alloy that is less energy-intensive to make, and requires none of the toxic anodizing processes. The fixture is highly segmented for adaptability, and all components may easily be removed if failure occurs, allowing for easy replacement of parts. I was shocked.

Two years ago, before I left Lam Partners to pursue a Masters of Architecture at the University of Michigan Taubman College of Architecture, white LEDs were standard in steplights and other specialty fixtures, but only just catching on in mainstream lighting design, with a few linear fixtures, floods and downlights. Those fixtures were not terribly competitive at the time.

Since returning to the firm for the summer, at least once a week a manufacturer has come to promote their new LED products. As one lighting manufacturer’s representative correctly noted, I’ve stepped into the future. The once over-priced and under-performing LEDs now stand beside traditional sources, and in many cases outperform them; costs are dropping while efficiencies continue to rise.

The LED revolution is obviously the greatest thing since sliced bread, the introduction of fluorescence, or of incandescence before that. But just as growing pains occurred at those phase-changes, this revolution too has seen a dark side. In this new world, the slightly ignorant marketer walks into our conference room spouting how their fixture is ‘sustainable’ simply because it uses LEDs, or maybe includes some recycled decorative glass. It seems fair to say that many manufacturers misuse the term ‘sustainable’ as a marketing ploy, with mixed knowledge of what is needed to create truly sustainable products.

I was therefore pleasantly surprised when this particular company actually walked the walk. They’ve produced a product that begins to address some unspoken facts of the lighting industry: lighting fixtures require vast quantities of energy to produce, ship, and install, and poorly designed fixtures equal waste.

The discourse on life-cycle costing was made popular by William McDonough and Michael Braungart in their book “Cradle to Cradle,” and for some manufacturers of architectural materials, it transformed the way in which their product is conceived, produced, bought, and utilized. Moreover, the general adoption of LEED standards has greatly influenced the purchasing power of clients, who, through their architects, now regularly seek architectural products that account for embodied energy in some way, such as sustainably harvested wood or recycled or re-purposed metals.

However, LEED does not currently allow MEP equipment to count toward credits for material usage, with the understanding that the material quantities are considered negligible, they are not permanent to the architecture, and ultimately their ability to efficiently use energy trumps any material concerns. This seems like a missed opportunity, as the material in MEP equipment is hardly insignificant, and in many cases could comprise recycled or re-purposed materials.

While operational energy accounts for the amount of energy consumed (power x time) by the product during use, embodied energy represents energy required to produce and transport the fixture, and how that energy becomes ‘trapped’ when the product enters the waste stream. A brick, for instance, has a relatively low embodied energy, requiring only the energy to collect the clay, fire it, and transport it, and then may be used multiple times before it crumbles and must be reformed (of course never once requiring connected load). The light fixture by comparison must be fabricated from an array of energy-intensive materials, like aluminum, steel, glass, plastics, and mined phosphorous (reserves of which, according to Wikipedia, we’re on track to deplete sometime in the next 100 to 300 years). These materials must then be assembled, requiring additional energy-consuming processes.

The current debate over LED lamps and fixtures exemplifies the necessity to think more constructively about lamp/fixture embodied energies and life-cycle costs. This is a two-part issue. First, LEDs are finding homes as retrofits: replacement lamps for old fixtures, and complete fixture replacements (as have also been seen with compact fluorescent or metal halide retrofits). If the fixture must be completely removed, the old product is often sent to the landfill, and in large-scale retrofits, this may be quite a sizable quantity of wasted metals.

Secondly, in the rush to get products out to market (for both retrofit and new construction), many manufacturers have created LED products with no option to replace failed components in the field, notably LED boards and drivers. Manufacturers tend to argue that, in order to achieve the desired output and long life, LED boards must be permanently attached to their heat-sinks, usually with some sort of thermal glue. This then gets extended to additional aspects of the fixture, including housings or reflectors. Apparently, to most manufacturers, in some glorious undetermined future utopia we won’t even have to worry about waste disposal… LEDs will last until our civilizations have long since perished, so it’s not even worth bothering with end-of-life issues. Unfortunately this leaves the end user with only one option when the fixture does, some time in the next 20 years (a brief blip in the realistic lifespan of a building), fail: completely remove the dead fixture and replace it with a new one. No governing body exists that demands that old MEP or lighting equipment be recycled or re-used in any way, so the manufacturer is off the hook.

One manufacturer suggested, as an option until they “figure out their policy on refurbishing dead fixtures”, that the specifier add the phone number of an ‘approved’ recycler into the notes column of the fixture specification, for the end user to contact at failure. This option certainly plays into the notion of American capitalism, but it is ultimately laziness on the part of the manufacturer. I would much rather put a note into the fixture schedule recommending that the end user contact the manufacturer or local representative to buy a replacement, at a discount in return for the dead fixture (assuming the fixture dies after the warranty period).

The manufacturer should be thrilled at this concept. They potentially regain a host of usable parts, which should be refurbishable, and moreover, they retain the business of the customer. This is already happening in the computer industry, as an alternative to shipping dead electronics to third-world countries where workers strip equipment under highly hazardous conditions.

For example, I currently have a three-year-old Macbook Pro. Still works, but running slow, and I’ll need to upgrade soon for school. Recently I went onto Apple’s website, and found that I could get a quote for my old laptop based on the model and working quality of specific parts (even if it was dead for some reason, I’d still get money back). By offering a trade-in for my old laptop that can be put toward the purchase of a new computer, Apple is not only able to recapture the energy they spent creating the old one (which can be refurbished and resold, or stripped for individual components), but they also retain my business for the new product.

Granted, Apple’s ubiquitous presence in local retail far exceeds that of any fixture manufacturer, so an alternative might involve local lighting representatives to build up quantities before shipping, which suggests that buying local MEP equipment also matters. Regardless, few if any lighting manufacturers have thus far marketed their products in this way.

The push to create highly energy-efficient, long-lasting LED replacements for inefficient technologies does allow for minimization of waste. But countless inefficient light fixtures are currently being pulled from ceilings in an effort to reduce energy consumption, arriving either in landfills (to be mined by future generations) or at recycling plants that must perform energy-intensive procedures to recapture materials. I would like to see future companies retrofitting old light fixtures with new light source technologies in the factory setting, and selling them alongside ‘new’ products. I look forward to the day when a high-visibility architectural project has only refurbished light fixtures installed. It may be my project.

Post-Script

As I implore manufacturers and lighting designers to consider life cycle as well as aesthetics and connected-load performance, the following are recommendations I would like to see incorporated into the ethos of the lighting industry:

To the Manufacturers:

In order to meet current LEED criteria pertaining to lighting, lighting must be incorporated into a design by an experienced design professional who is able to balance connected load energy usage and reduce light pollution across a complete layout of fixtures. In no way can an individual fixture really “help meet LEED” on its own terms. Blanket statements like these reveal the manufacturer as using jargon and marketing instead of truly attempting to make sustainable products.

Regardless of current LEED criteria, every material choice within a lighting product requires energy for production and disposal, beyond just connected load. These choices will begin to matter more to consumers in coming years. Prove that your fixtures were created sustainably, shipped sustainably, and can easily adapt to changes in technology or component failure for the lifetime of the architecture.

Components that may fail must be replaceable without requiring costly and wasteful entire fixture assemblies. When a fixture truly reaches the end of its useful life, provide robust programs that allow end users to return fixtures beyond warranty periods for rebates on replacements. Refurbishing the components of dead fixtures equal potential savings by keeping highly usable materials out of the landfill.

If in fact your products do go the distance, market these specifications! Is the fixture made of 100% recycled aluminum? Put that on the spec sheet! Can the plastics be disassembled and recycled? Clearly stamp those materials with the well-known ‘recyclable’ symbol with material type (in a location that will not affect light performance).

And finally, or course all manufacturers should commit to ‘greening’ operations and products – but do not roll out one product as your ‘sustainable fixture’ without also providing a plan to overhaul the rest of your product line and manufacturing operations. It’s hypocritical.

To the Designers:

Why not specify refurbished lighting products? Must the back-of-house troffers be made of pristine aluminum? Actively look for ways to minimize not only watts, but material-heavy fixtures, with preference given to the lighter, refurbished, or recycled products. Minimize the use of fixtures made from materials with energy-intensive or toxic manufacturing processes.

How can the architecture itself serve as a lighting system? Thoughful design can allow for replacement of the minimum quantity of material when technology changes, and allows renewable materials to do some of the lighting work, such as in valances or coves.

Finally, demand more from your product manufacturers. Lighting may be a relatively small piece of the puzzle, but it’s the piece over which you have control. Make the most of it. Specify high-performance sustainability.

Photo Credits: Dan Weissman / Lam Partners Inc

Lighting design hasn’t changed much since someone first decided to call himself a lighting designer. Twenty years ago, the most earth-shattering developments were in fluorescent lamps; ten years ago saw advances in ceramic metal halide; today we’re cautiously welcoming LEDs into regular practice. LEDs really do have the potential to displace a lot of the existing technology, once we’ve smoothed out all the bumps, but even technological jumps of this sort won’t completely address the energy crisis we are facing. Yes, LEDs will give us more light per watt, but they still produce heat and we’ll have to get rid of it somehow. We’re still using energy. So what else is there?

Buildings, as we build them now, are barely more efficient than they were 50 years ago, even the LEED ones. What are we doing wrong? We are pushing the limits of our technology but we continue to increase our per capita energy consumption. To borrow an oft-used quote, Einstein defined insanity as “doing the same thing over and over again and expecting different results.” Perhaps our efforts to design better simply haven’t been enough, to the point that we’re essentially doing the same thing over and over again. Sure, using fluorescent lamps and super-efficient fixtures en masse throughout a building can make an impact, but is it enough to make the fundamental leap to save us from ourselves?

So, are we too cheap? When it comes time to pay the bill, do we argue about what’s on it, or look around and ask others to chip in? Ask yourself, as a designer, how many times have good, common-sense design elements been deemed expendable when the budget hits the fan? And when those tough decisions are made, what takes precedence over sustainable functionality? Immediate satisfaction! More square feet per dollar – that’s the sad bottom line. Next time you consider skimping on controls or settling for that less-efficient pendant, consider the big picture: eventually all those 1% savings here and there can add up. Budgets need to support projects in their entirety and keep what really matters. If it means sacrificing marble floors for more daylighting, do it! We’ve gotten off too easily for too long on the cost of responsible building.

Or, perhaps we’re all lazy. Take an example: as an undergrad I spent a summer in the wonderful city of Portland, Oregon, and was awed by what I saw there. Buildings without any air conditioning! Now, I’m not so sheltered that I’ve never seen a building without AC – I grew up without it – but I was astonished to see large commercial buildings without it. The climate obviously had a lot to do with it, but, when you looked around at the older architecture of the city, the pre-AC stuff, you saw that they simply designed the buildings to function without it. Big windows, high ceilings, narrow floor plates, atria, architecturally integrated daylighting, and on and on. Those designers relied almost exclusively on passive systems and when the sun went down, people went home.

The point is that all of our wonderful innovations, however efficient, have made life so convenient and comfortable that we’ve detached ourselves from the natural environment, from house to car to office. Life is actually too easy for the majority of people. Look at the nation’s waistline as an indicator. We work late because we can (the lights and AC stay on) and, consequently, we exercise less. We use more electricity by working on the fringes of the day (fewer people in the office, but all the lights are on) and even though the lights are more efficient than before, we leave them on longer. Net result: same energy use and fatter people. Just recently, the BBC published a story citing: “People who regularly put in overtime and work ten or eleven-hour days increase their heart disease risk by nearly two-thirds, research suggests. The findings come from a study of 6,000 British civil servants, published online in the European Heart Journal.”

One more guess then: is it vanity? Just because we can build all-glass buildings doesn’t mean we should – all that heat-gain and glare. Just because we can make floorplates 200 feet thick doesn’t mean we should – they only exist on life support (i.e. electricity). Just because they make light fixtures that are two inches wide doesn’t mean we should use them – those two-inch-wide fixtures are super inefficient, by the way.

Exceptional design and creativity can promote advances in technology, and those advances fuel, in turn, exceptional designs. But if an aesthetic that technology can’t efficiently support takes priority over the energy use, the cost of pretty goes way up. Is there another pretty, or could you do it another way entirely? Can practicality and originality coexist?

If it’s all or none of the above, one thing is sure: we need to make a sacrifice and adjust our values. To quote Thomas Friedman in a recent New York Times editorial:

Our parents were ‘The Greatest Generation,’ and they earned that title by making enormous sacrifices and investments to build us a world of abundance. My generation, ‘The Baby Boomers,’ turned out to be what the writer Kurt Andersen called ‘The Grasshopper Generation.’ We’ve eaten through all that abundance like hungry locusts.

Now we and our kids together need to become ‘The Regeneration’ – one that raises incomes anew but in a way that is financially and ecologically sustainable. It will take a big adjustment.

Not only do we need to radically change our building designs but we need to use them way more efficiently. We need to change our habits – turn out the lights, or not use them at all.

Photo Credits: ume-y (1), code_martial (2), BLW Photography (3)

Lighting systems have gotten vastly more efficient in the last decade. This is thanks to better bulbs, better luminaires and controls, and better lighting design – and let’s all keep working hard to make them even more efficient as technologies and design methods continue to improve. But, let’s also give ourselves a little credit for the great progress that’s already been made. For example, we’re now designing office lighting using one-sixth of the electricity typically used just 25 years ago. Imagine if we had made the same kind of progress with automobiles.

Stop reading for a minute and ask yourself: how much energy do you think you use driving to work, versus how much you use to light your personal share of your workplace? What is just the rough proportion you would guess? Let’s put some numbers to that:

Let’s say you drive a new car at the US average of 16 miles per day each way, and you average the current federal standard, 27.5 miles per gallon. That consumes a bit over a gallon of gas per day.

The same amount of fuel oil, burned in a typical power plant and distributed to your building through the grid, at an overall efficiency of 30%, will generate 14 kilowatt-hours. If you work in a 200-square-foot office and your workspace lighting power conforms to current ASHRAE standards, that gallon or so of gas will light your workspace for over 65 hours. Or, to put it another way, the fuel you use getting to work each day will light, for ten hours, not just your 200 square feet but actually 1,300 square feet – enough space for you and half a dozen friends.

How is that possible? Well, for one thing, when you stomp the accelerator on your base four-cylinder Accord (177 horsepower), in electrical terms your modest sedan is generating over 130,000 watts, and it’s doing it inefficiently. At that rate, it would take you less than 60 seconds to burn up enough fuel to light your workspace for ten hours.

Actually, our estimate is very conservative. If we get more realistic and factor in the inefficiency of refining and transporting gasoline, and we recognize that new buildings are required to have motion sensors to turn your lights off when you don’t need them, and we also recognize that the average American commuter vehicle doesn’t average anywhere close to 27.5 mpg (okay, and maybe your office is less than 200 square feet), we can come closer to a realistic answer to our initial question. And that answer is that if your workplace meets today’s lighting energy standard, your commute likely uses at least ten times as much fossil fuel as your workspace lighting each day.

So, how did you do on your guess?

Photo Credits: Skippyjon (1), MadMarv00 (2)

Interior honeycomb shades provide privacy and additional insulation, and are a part of the nighttime ambient lighting system in Team Boston's house.

I was fortunate to be able to spend the weekend visiting the Solar Decathlon houses on the Mall in Washington, D.C. (see the Solar Decathlon website and Amber’s last blog article “Curious” About Sustainable Design?).

Miserable weather meant that the houses weren’t generating much electricity, but the energy produced by the students attracted many people like me willing to stand in long lines in the rain and mud to see their work. I was impressed by the sheer immensity of what the students had accomplished (none more so than the Lam-sponsored Team Boston!) and the many ways in which each team solved the same sets of design problems. It was fascinating to see how they balanced the tensions between having to make a highly efficient house that also functions well, would be a nice place to live in, and is beautiful. You could see the compromises: the house that was super-insulated but didn’t have many windows, or the house with large south-facing windows but no architecturally integrated shading to block the summer sun (perhaps because it would have violated the purity of the architecture) – or the house that kept the lighting energy so low that the lighting quality suffered.

Team Boston's southern façade featured an integrated shading overhang and innovative roll-up exterior louvers for no summer solar heat gain.

But the thing that struck me most about the competition was not something I saw on the Mall, but an entry in Thursday’s Daily Journal on the Solar Decathlon website. In describing the winners of the Lighting Design competition, it said: “A Minnesota team member commented that their goal was to use only 500 watts (or the equivalent of five incandescent light bulbs) to light the entire house”. Now, I appreciate the attempt to make the information accessible to the average consumer, but this comment is so telling about the incorrect way that the world considers lighting energy efficiency.

This type of vanity mirror seen in Penn State's bathroom showed up in a few other houses, too. Love the skylights!

The Solar Decathlon is a contest that measures (among many things) energy-efficiency, not total watts. Energy is Watts x Time (see my blog article Fight the Power! ) So I could have 2,000 watts of total lighting in my Solar Decathlon house, but if I only needed to turn some of it on for a small amount of time each day, I could use less energy than a house with 200 watts of total lighting that had to have all the lights on most of the time. If they only measured watts at the Solar Decathlon, then all they’d need to do is hook up the houses to a meter, make them turn on every system and appliance, and the house with the lowest wattage would be the winner. Well, that would be easy – but it would be dumb. So why, then, do we talk about lighting performance this way?!

So there I was on Saturday in one of the houses and a charming student tells us that all their lighting uses only 200 watts. Sigh. And then later that afternoon, in another house a student tells us how their LED fixtures use just 3 watts each. Arrgghh. So OK, we’ve done a bad job educating our students about how to measure lighting energy efficiency, but this also brings up another timely issue: lighting quality. What if you only use 200 watts but lighting quality is poor?

Finelite's LED task lights provide great bedtime reading lights for Team Boston.

And then, as expected, the LEDs were everywhere along with the hype. Several houses proclaimed that all their lighting was LED, as if just saying that indicates some special level of energy efficiency. And of course, as we were told at one house, “LEDs are seven times more efficient than an incandescent light”, when realistically they are maybe half that. Where do they get this stuff? And it’s not just efficiency misinformation, but the lighting quality issue too. Far too often, the LED sources that I observed were glary and had a ghoulish cool color. If the Solar Decathlon is a predictor of trends in residential lighting, then we might conclude that we have a lot of glare in our future.

Another comment I overheard that I thought was telling went something like this, from a gentleman standing below one of those glary LED accent lights: “Gee, if we could only get LEDs that were good for ambient lighting”. I almost went up to him and said, “You have a much better source already – linear fluorescent – twice as efficacious as LED, and much less expensive.” But I kept my mouth shut and wandered out into the rain and mud thinking that we Lighting Designers have to do a much better job educating students and the world about how to achieve true lighting energy efficiency and lighting quality.

Some serious lighting bling from Team Germany.

Photos Credit: Glenn Heinmiller / Lam Partners Inc

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)

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?

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.

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)