Using a lighting construction budget to select fixtures and understand color quality, part 2
Tony Staub discusses how a lighting construction budget requires careful selection of fixtures and understanding of color quality, while carefully navigating changing costs per square foot
- Understand the owner’s project requirements (OPR) for lighting. Understand how to design lighting systems to meet the OPR.
- Lighting construction budget can be challenging to determine, as it is often presented as a dollars per square foot figure, making it difficult to understand the actual project needs and implications of different budget levels.
- When working with a limited lighting budget, it is important to be conscious of the fixtures specified and consider more economical options like flat panels instead of high-quality downlights, while still ensuring a high-quality solution that aligns with the design goals.
- Effective communication and education about lighting choices, including fixture selection, color quality and color rendering index, can help ensure that the client, contractor and project team are aligned.
Managing a lighting construction budget can be challenging due to the variability of costs per square foot, requiring experience and careful specification of lighting fixtures to fit within the budget, while considering aspects such as functionality, aesthetics and color quality, which includes understanding factors like color rendering index (CRI) and color temperature.
Tony Staub, PE, LC, lighting design lead/electrical project engineer at Specialized Engineering Solutions discusses building a lighting construction budget and the different variables that go into it in the Consulting-Specifying Engineer webcast “Lighting and Lighting Controls.” Read about part 1 here.
The following has been edited for clarity.
Tony Staub: Lighting construction budget is one of those things that can really be difficult to pin down, especially early in the project, you’re typically going to get a budget that is presented in a dollars per square foot number and that can be difficult to relate to what the actual project needs are. What does $5 per square foot for lighting versus $10 per square foot for lighting mean? And that’s something that, in my opinion, starts to come as a factor of experience. From experience, I would know if I see a $5 a square foot lighting budget, I know that’s going to be pretty tight, hard to hit, but I know that my standard products can be more economical product.
I’m going to be looking for, maybe more flat panels instead of high quality down lights. But always looking for ways, especially in those fixtures where you’re using the hundreds of fixtures, your “type As” that you are conscious of the budget so that you’re not specifying a high-end product when the budget. It can be very beneficial to try to get the budget broken out when you have higher finished spaces within a project, but maybe the lighting budget is $5 per square foot throughout the building. However, then there are a few spaces where the owner wants the higher finish level and they’re willing to carry a separate decorative lighting budget and that can pay for things like sconces and coves and feature pendants and any number of other things going on there.
It can be difficult. You want to communicate early and often and you also want to communicate the value of why you’ve selected the fixtures you are and why you’ve done the design that you’re doing. That’s because lighting tends to be a very easy target once value engineering starts on a project. Sure, everyone’s been in one of those meetings where the contractor will raise their hand and say, “I can reduce the lighting budget by 25% if you let me select the fixtures.”
But from a lighting engineering standpoint, there are a lot of key important things and we’re going to get into a couple more of those. I want to make sure that my client is still getting a high-quality solution that I can stand behind, regardless of where that budget sits.
Be conscious of what you’re specifying because if you’re specifying for a budget, you could end up in a situation where you’ve spent too much money and now you’re going to have to value engineer to something that isn’t meeting the design that you wanted. That can also help if you get the contractor in a little bit early. If your contractor understands what you’re doing and this is especially true on the control side, your budget might end up looking better as you move through the project. The reason I say that’s especially true for lighting controls is we still have the network lighting controls — the digital addressable lighting control systems — are still new enough that contractors may struggle with the installation of those. If they’re not familiar with how the installation’s going to work, then you typically see much higher installation costs than what’s truly necessary.
Educating both your client, your contractor and really the whole project team, as to what you’re doing and why can help you ensure that you keep the design that you want. I throw an example up, one thing that I do to try to lock it in early is as soon as I can get even the preliminary floor plan and a budget, I start to go through and just color code plans. This is high level and you’re not making final selections, locations, quantities or anything like that. But what you’re doing is starting to relay that information of high level, what is my plan in each space type?
You can help yourself decide that by learning a little bit more about what the client’s needs and wants are. Fixture selection is going to be a big one. There are thousands of different fixtures that you could put into your project. There’s going to be aesthetic choices, there’s going to be budget choices and there’s going to be functional choices. These fixtures are performing differently too. All of those things start to add up and are part of your fixture of selection process. Like I said, I usually try to get this started at schematic design and then ideally you can get that locked in at the design development level with a fixture package that you can deliver to the team so that everyone’s on the same page and understanding what the fixtures throughout the space are going to look like. A couple other things that I think that you should keep in mind that can really be critical are color quality and CRI.
I would advise you to think about the spaces you’re in. CRI 80-plus is very typical. That’s what you’re most often getting from lighting manufacturers. CRI 90-plus tends to be a minimal cost edition and is relatively easy to get, even when it doesn’t necessarily say that it is. There are a lot of benefits that you can get by moving to a higher CRI. I mentioned earlier I’m in health care and do a lot of health care engineering. I don’t put any light in health care space that is not 90 CRI.
Just the benefits of being able to get the really true-to-life color rendering so that a physician can look at your skin tone or your eyes or whatever thing they’re looking at, even discrimination between two different pill types. Maybe you have a pink pill and a maroon pill and they’re the same. You need to be able to tell the difference so that you don’t misapply those things. Health care is one example. You have art in space that could be another example. Interior design studios love to have higher CRIs so that they can really see what those materials look like in the true lighting that they should have.
Another thing that your client might care a lot about, even if they don’t understand that they care a lot about, would be the color temperature. We see that color temperature tends to be preferred in regions in different ways. Here in the Midwest, 3,500 Kelvins still by far the most common. I know there are places where even 5,000 Kelvin can start to be more interesting or is more preferred depending on the space.
I have just a little box that has different colored LEDs ranging from 2,700 Kelvin to 5,000 Kelvin. Most of the time when you approach a client and you start to talk about color temperature, they understand different color temperatures. Everyone has seen warm and cool and understands what that means, but they don’t know what does that actually mean for their building. What am I going to get? What am I going to see?
They’re relatively easy to get, talk to a rep and see if one of them has a tool for you. If you can just show them 3000, 3,500, 4,000 Kelvin being some of the most common ones that really helps them to understand what decision they’re making. A lot of times the answer you’re going to get is just match what we have. This is a brand-new building with a brand-new client. You might have to go through that educational process.
Understanding lighting control systems
What about the lighting control system? In my experience, the energy code mandates what you’re going to get. You should definitely be having these in-depth conversations with your owners or with your clients. The reasons for that is a lot of times and especially as we’ve moved to this new era where we’re getting more of these digital interconnected controls, clients are starting to have more interest in how they interact with those controls. At the end of the day, with most of our projects, we’re trying to meet those energy code minimums that we have to do. ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings is very popular there. In Nebraska we use mostly the International Energy Conservation Code (IECC) and that’s largely because of the receptacle requirement. We don’t have that exception. And very, very few people want to turn off their receptacles.
So IECC is common here, but really what we’re looking at is what is the code making us do? We can look at other layers to save more energy, be easier to use, whatever you want to do, whatever the client wants to do. But ultimately, we must know what are the things that we must do. One of those that has really changed a lot as newer codes have been picked up. I believe this started in IECC 2012 and I think just the previous ASHRAE for that, but one of the biggest changes that has happened over the last number of years was the, once you’ve met those energy or once you’re at that enforced energy code, you can no longer have an occupancy sensor turn your lights on to a hundred percent. A lot of these new codes are no greater than 50% and there are exceptions as well. That was such a common design for so many years that now you start to have to think about how we’re going to do that a little bit differently.
What about building on from that? I talked about the code requirements and what really tells us what we must do. If your owner gets a little bit deeper and wants to dive in, you can start to have really, really in-depth conversations about your controls. Part of this is driven from the fact that the industry hasn’t really standardized on much once we’ve gotten to this new level of controls. A traditional slide dimmer with a switch has many other alternate devices that do the same thing that that dimsmer does. All three of them look totally different. You’re going to interact with them in a totally different way, but at the end of the day, they do the exact same thing as that slide dimmer. Your owner might have a preference. I know I do when I’m selecting switches and I’m selecting those types of things. %hat’s just at the most basic manual control level. Our systems now are so complex where we can do things like load shedding, things like schedules and things like that.
If they want a floor planned view to be able to pick up anything and everything and know exactly what the lighting status of a light in the storage room is while they’re on vacation in Mexico that’s fine. We can do that. We can get that set up. It’s all about a conversation with your client about how deep do you want to go. Are we only trying to meet code minimums? Or do we want to take advantage of some of these extra pieces that we can do? What does the end user have to interact with? Are they familiar with the buttons? Do they know they can dim? I can’t tell you how many times I’ve been at a post occupancy walkthrough and people complain about a room being too bright and I’ll dim it and they look at me like I’m some sort of magical wizard. Like, “Oh, you’ve just changed my life here.” A lot of conversation can help you with that lighting control system, if you have a client that’s willing to engage with that conversation.
I wanted to take a moment to talk directly about daylight harvesting because it can be a really tricky and it’s probably one of those fun code lighting things that can be tough for you. Both IECC and ASHRAE have defined daylight zones now. ASHRAE 90.1 does have secondary daylight zones. I did just investigate 2021 and IECC does add secondary side lit zones as well. Daylight harvesting is only becoming more required as codes get newer and newer. There are more and more spaces we’re having to do daylight harvesting and really save all that extra energy. Definitely something that if you’re not familiar with and start studying now because it’s coming. There are two common methods used in the industry now and that is open loop and closed loop, which is essentially just saying, are the photo sensors looking at the space? Are they looking at the desk that I’m sitting at, judging the light there and adjusting accordingly?
Or are they looking at outside? That includes if it’s looking at a window or if the photocells actually located outside of your building. Both can be effective in different circumstances. Generally, we are doing the close loop or generally for me, we’re doing the close loop designs that are so within a space, but especially when you get higher ceiling heights, is a big one. If you have a lot of indirect light and the picture on the bottom left there of the daylight, even that one would make me a little bit uncomfortable. There’s a lot of up light that’s hitting that sensor. Depending on your site conditions or your room conditions, one may be more appropriate than the other.
I want to walk through the steps that are needed to start. Every project can be a little bit different, but how do you start from step one and get to designing a lighting system that meets the owner’s project requirements that we just talked about? Projects start anywhere. Sometimes you are thrown in at step three here and you say, “Well, here’s a project and it’s due next week and start laying out lights.” That happens, right? But if we have our way, you want to take that a little bit slower and a little bit more methodically. Ideally you can start by identifying the needs of your space.
This is the one that can be really difficult for us as electrical engineers. This is working with your architect, your interior design and the rest of the team and this is where you have to think about using a different language than you might use as an electrical engineer. You want to be able to speak to the feeling of the space and the goal of how that space is supposed to be perceived. At this time, you really shouldn’t be talking about fixtures at all. I don’t want to talk about a downlight or a cove or this or that.
I want to talk about where light should be. And a lot of times this is where sketching can be incredibly valuable because you’re not trying to get fine details. You’re trying to convey what spaces need to be painted with light and what parts of the canvas is most important to us from a lighting design standpoint. Then you can start to select the pieces and the parts that you need to get there. If you don’t know what the feeling’s supposed to look like, what the design’s supposed to end up as, then how do you get to that design? You’re just guessing if you don’t really have that feeling in your head ahead of time. That’s when you move on to the engineering of this. You already know what foot candle requirements you have in the space. I know-how it’s supposed to feel, which has helped me decide which fixtures I’m going to end up using.
And now, how many of them do I need? Where should they go? That’s where you start to get specific, perform your calculations, do your layouts and work from there. Then you make the cleanest plans that you can. We all don’t want to have to answer requests for information. If you can make a very clear, concise way of delivering that information that’s obviously going to be best. Detailed lighting can get really difficult. I’m a big fan of using a published sequence of operations on your plans to really let everybody know, at least what the lighting control system’s going to do or intended to do. That’s ultimately where you need to end up because somebody’s got to build it.