- Investing in the Building Envelope
How to Build Green At No Added Cost
Avoiding cost premiums on green projects is not only possible: it’s a good idea, focusing design teams on simple, effective designs that can deliver savings for years to come.
By Tristan Roberts
Reduced operational costs, improved occupant health and productivity, and buildings with small ecological footprints: these are the ways we make the case for green buildings.
What about first cost?
Perhaps to the detriment of green building adoption, we’ve been letting cool premium products and innovative demonstration projects paint a picture of higher first costs. It doesn’t have to be that way, say architects, engineers, and developers that EBN spoke with. Using constraints to feed creativity, plenty of projects are not only choosing no-brainer, no-added-cost measures to go green but are also using their dollar budgets as a signaling mechanism to find cheaper, simpler, and more effective designs.
What Should a Green Building Cost?
Before reviewing strategies—largely focused on the building enclosure and mechanical systems—for reducing first costs, is the first cost of green something we should be even putting under the microscope?
A surprising answer comes from Greg Kats, a green venture capital advisor and president of Capital E. He told EBN that asking green buildings to cost less is the wrong approach. “We don’t want a healthy, efficient building to cost the same as an unhealthy, inefficient building,” he complained, arguing, “It’s a premium product, and it should cost more.” Pointing to 2% first-cost premiums as a frequently cited number for green buildings, Kats asks rhetorically what other industry offers its “premium” product with such a low cost differential. Premium cars, clothes, and restaurant meals, to name a few things, are easily 50% more expensive—or higher.
Green means quality, says Kats, and not only should we expect that to cost more, but we should also do our part and pay up. “If it doesn’t cost more, you are buying high-volume products, which means you’re not buying low-volume products”—in other words, not helping develop the market for innovative materials with reduced environmental impacts. “Green building is an engine to accelerate and reward innovation,” he says. In Kats’s view, green building is like the national space program or a premium automotive line: costly innovations that it introduces gradually become more common, while the premium models raise their sights.
Clark Brockman, AIA, of SERA Architects, says that whatever project teams charge for green buildings, they need to focus on the needs of the market and making a case for green. “We’ve gotten a lot better at making green buildings, but we haven’t gotten a lot better at making the value proposition for them for the market,” he says. “I genuinely believe it’s a better product, and it’s incumbent on us to present the better product to the market in the way that market says, ‘Wow, that’s a better product—I want to buy it.’” On first costs, Brockman says that, in his experience with price-sensitive developers, the case can be made for relatively incremental add-ons, especially in the building envelope, to deliver a higher-performing product.
According to Peter Morris, director with AECOM, the market is transitioning. A coauthor of two previous reports on the cost of green buildings (see “”), Morris says that an updated version of that report will show that work by early adopters is driving performance up and cost down for larger projects. “There was a first wave of very high-performance buildings that tended to be relatively small and relatively very expensive,” he says, and in many cases, they were intended as demonstration projects for green approaches. “More recently, we are seeing a following wave of buildings that are much larger, slightly less complex, maybe a little less high-performing, and their costs are coming more into line with the general population.”
In the future, the price of a green building will represent the market norm, with lower-performing buildings falling behind, predicts Brad Molotsky, executive vice president for Brandywine Realty Trust in Pennsylvania. “If people value this,” he says, “then they may not be willing to pay more for it; they just won’t be interested in buildings that don’t have these features.”
If Molotsky is right, green buildings will overtake the market and thus define market rate. In the present tense, though, project teams are finding creative ways to provide premium quality at market rates or convince clients that some things are worth paying more for—usually some of both.
Shrinking the Building
There is no better strategy for building cheaper than to build less. Faced with lean economics, many projects are scrutinizing their programs for savings, and with telecommuting on the rise, moving toward space-conserving open offices and multifunctional spaces.
For a new library on the Sacred Heart Lower and Middle School in Atherton, California, Pauline Souza, AIA, of WRNS Studio, says that “every space mattered” in designing the net-zero-energy, Living Building Challenge project “on a shoestring.” She notes, “There are office spaces that double as small classrooms for kids, meeting rooms that can turn into office spaces,” and large assembly spaces that can be turned into classrooms. The architecture is simple, with outdoor circulation, and the building is naturally ventilated.
“Finding elements of the building that are doing more than one thing for you” is a proven green strategy and a major cost saver, agrees Bungane Mehlomakulu, P.E., principal with Integral Group, who emphasizes that the mechanical engineer can help the architect. If your building envelope can be efficient enough to meet cooling loads with active chilled beams, says Mehlomakulu, then you can reduce the amount of ductwork—a major cost savings in labor and materials. “What that also means is that you don’t need as much plenum height to run your systems,” allowing reductions in floor-to-floor height of 6 to 12 inches, as he was able to do on a four-story structure in a seismic zone. That size reduction in turn reduced the amount of building enclosure, reduced the structural requirements, and even paid off architecturally: “the building didn’t look so heavy from a massing standpoint,” he says.
The same strategy works on tall buildings, according to Luke Leung, P.E., sustainable engineering studio director at Skidmore, Owings, & Merrill. Leung has proposed using dedicated outdoor air systems (DOAS) with fan coils and radiant ceilings in selected office buildings. The reduction in ductwork, replaced by piping, saves eight inches per floor compared with conventional variable-air-volume (VAV) systems while saving energy, and he says it’s about 9% cheaper in first cost. In a tall building, he says, you can add four stories while keeping the same ceiling and building heights.
Why isn’t DOAS more common? According to Leung, the obstacle is the greater amount of water piping that it relies on to deliver heating and cooling, and that in turn means greater risk of leaks and condensation. Rather than treat that as an obstacle, however, Leung says that greater attention to detail in sealing and insulating the envelope as well as pressure-testing piping can stave off problems—and also saves energy that might have been lost to air leakage without this extra care. “With a ducted system, you may be paying a high premium for the leakage but not know about it,” he says, while you’ll know about a leaking water pipe right away.
Investing in the Building Envelope
Investing in a higher-performing building envelope in order to reduce the size of the mechanical system is the oldest trick in the book for reducing green building costs, but it remains as relevant as ever, argue many engineers.
Pay it forward
EBN spoke with Kim Shinn, P.E., principal with TLC Engineering for Architecture, who draws a hypothetical contrast. One building has 100 tons of cooling load and a sophisticated cooling system that draws a maximum of 50 kilowatts. In a second building, envelope investments and other cooling load avoidance strategies have netted a 30% savings, dropping the peak cooling load to 70 tons. In that building, Shinn might put in a somewhat less efficient, less sophisticated, but simpler and less costly cooling system, also with a peak power demand of 50 kilowatts. Which building would you prefer?
While a lot of engineers—and architects—no doubt prefer the higher-tech approach (combined with a sleek but poorly insulated all-glass curtainwall), green engineers EBN spoke with for this article tend to prefer the lower-cooling-load, less-sophisticated route. But in order to achieve that, they need to be there when the load gets decided—early in the design process.
In the past, Galen Staengl, P.E., principal with Staengl Engineering, says that engineers have pushed to use very complex, very efficient (and very expensive) HVAC systems on green building projects, but “in the last couple years, I’ve been questioning that approach and whether it’s best for the whole project. Some of that cost can be shifted to the envelope, which is more durable and less prone to failure,” he points out.
“Designs can get too far down the road before you can get some of these load-reduction strategies in place, and it makes [them] a lot harder to implement,” Shinn says, arguing that good decisions early in the design process will always put projects ahead. Adding design time with a larger team early on can increase certain costs—but, Shinn says, in addition to lower-cost designs that cost less to operate, those designs can get built sooner because doing the work early streamlines later design processes.
Mehlomakulu says that as an engineer, he’s happy to free up investments in the mechanical system for use in the architecture. “We want to take money out of our HVAC budget and put it into passive approaches which are architecture-driven,” he says. Examples include overhangs that reduce cooling loads and serve an architectural function, adjusting the building orientation to bring in indirect daylight, or adding exterior shading to a heavily glazed lobby.
Windows coming down in cost
Windows have typically been one of those areas where a higher-performing project can expect a higher investment, hopefully balanced out by a smaller mechanical system as well as improved comfort and lower operating costs. Although the cost premium for higher-performing windows isn’t likely to go away, reports suggest that projects have been able to push for better windows while keeping costs in check.
According to Staengl, on a multifamily project in Virginia, the team was able to find a line of triple-glazed windows that were cost-competitive with the double-glazed system they might have typically used. The product isn’t Passivhaus certified, but its performance metrics were close. Staengl says that windows have been a big driver of cost premiums for Passive House, but that premium “has really been going down quickly over the last couple years.” And as with other factors, cost premium is always relative to something: on a campus project, Staengl says the team was already planning to use custom high-end windows, so going to triple glazing wasn’t an added cost.
According to Peter Rumsey, P.E., a consulting engineer, codes in California following the 2000 energy crisis there mandated double glazing for commercial buildings, which had previously not been widespread. Virtually overnight, he says, double glazing went from being a special-order product with double the installed cost of single glazing to having only a 10% to 15% premium. In reality, double glazing should have a relatively small cost premium of 10%, says Rumsey, but “when it was a specialty item, it was overpriced,” and there was little incentive for the market to correct that.
Brockman says that improvements in glazing have been an easy sell, even to very cost-sensitive developers of multifamily properties that he has worked with. He has substituted a higher-performing glazing for standard on otherwise mid-market windows, and although there is some added cost, the payback is so significant that the developers feel that the value of the project and ease of sales are immediately enhanced.
, in which windows can be tinted on demand or in response to sunlight, reducing solar heat gain, is definitely more expensive than conventional glazing, but it can pay off, says Mehlomakulu, who is looking at it currently for a small office building. He expects that it could shave peak cooling loads enough to reduce HVAC equipment costs, and it could also obviate the need for shading in a building with a major western exposure and potential glare issues. Mehlomakulu sees cost savings in removing shades, especially if they are mechanically operated, because electrical installation adds costs. (See our review of .)
Letting preferred materials compete for business
Much of the cost of the building envelope is in labor, so while less-toxic alternatives to products such as insulation can cost more, they may not drive the overall envelope cost as much as one might think. Emphasizing that point is Adam Cohen, an architect with Structures Design/Build in Virginia, who says, “If you make a design decision too early and lock it in, you give up the opportunity for savings down the road.” A lot of the cost, Cohen says, can come down to how “one contractor does or doesn’t like that kind of work.” Rather than assuming that a conventional product like extruded polystyrene (XPS) is going to cost less, and then locking it in prematurely with drawings that become too costly to change later, Cohen will leave two or three options open to contractor pricing, as he did on a dormitory project where mineral wool ended up outcompeting XPS.
Mechanical systems matter in the context of building envelope and massing decisions, but engineers are also doing a lot to bring in green buildings at low first costs just with a focus on their designs and load calculations.
“Right-sizing [mechanical systems] is a really important part of making a green building affordable,” says Rumsey. “I hear story after story that systems are running at 5% or 10% of their loads,” and projects have to put in a small supplemental “pony” boiler so that the main boiler isn’t constantly cycling on and off. In order to right-size systems, Rumsey says that teams should look at what the actual number of occupants will be in the building, not sum the maximum capacity of every conference room and office.
Keeping a close eye on the specification and procurement process is also key, he says. In a hypothetical example, the average load of a building might be 50 to 100 tons of cooling, but to account for peak loads might call for a 200-ton chiller. Adding a 20% safety margin on top of that gets a 240-ton chiller, but the closest the manufacturer offers to that size is 275 tons—but “then the guy selling the equipment says we actually have a 300-ton unit that’s ready to go; let’s sell them that.” Pretty soon, the project has bought three times the chiller it needs for its typical load.
Galen Staengl gave an example of a strategy he has used to optimize for both first and operating costs. On the Malcolm Rosenberg Hillel student center and sanctuary in Blacksburg, Virginia, the base load conditioning was provided by an energy-recovery ventilator (ERV) with a passive ground loop for preconditioning and dehumidification, and solar hot water for heating. That’s a high-performance, higher-cost system, but he saved money by not sizing it to meet the needs of a higher-occupancy sanctuary space that was occupied only for a couple of hours a week. That load is met by a more conventional, less efficient, split air-source heat pump.
Laura Lesniewski, AIA, principal at BNIM, says that projects can get trapped into over-sizing electrical, mechanical, and lighting systems due to “rules of thumb” that may not match the project. She suggests checking out a client’s existing space for lighting and plug loads, for example, to “demonstrate what the actual loads are in different areas.” By measuring the actual equipment, “you can gradually become more comfortable with being more aggressive” in sizing electrical services and cooling equipment.
As Amory Lovins has famously pointed out, a huge fraction of energy used worldwide is spent simply overcoming friction. Citing this, Rumsey makes a point of designing piping and ductwork systems that have reduced resistance to flow, by laying them out with fewer sharp turns and quick transitions—as well as using lower pressure-drop coils, air handlers, and chillers. That design work can translate to larger-diameter pipes and ducts, adding costs, but Rumsey says it saves on downsized pumps, ultimately reducing first and operational costs.
Letting the process lead the way
Adam Cohen puts an especially heavy emphasis on integrated process as key to delivering Passive House-certified buildings at no added first cost: his firm built a dental clinic for $155 per square foot, in the context of a regional average for the building type of $150–$200.
“We leave things as open as we can,” Cohen says about the design-build process, allowing insights about the building program and pricing to influence decisions. On a new dormitory project where the owner wanted to provide room-by-room comfort control, the project team first looked at mini-split heat pumps but found that even the smallest “heads” on these systems were oversized for the dorm rooms. Traditional fan-coil units were too expensive, with lots of piping and extra pump energy. Looking at what the project had to work with, recirculating hot water came up as an opportunity because that is standard in hot-water supply systems for many residential projects. The team found a company making a fan-coil unit that can run off potable water piping. After incorporating that, “the only thing we had to do was add a return line on the cold water and put that extra pump energy on the chilled water,” says Cohen. “All of a sudden, we could do it affordably because it was just another plumbing fixture.”
On the dental office, Cohen took advantage of another sunk cost—an onsite water detention pit that had to be dug on the project. At the same time, he was looking for a way to address the most common comfort complaint in dental exam rooms: patients are cold while the dentist and dental hygienist get hot. For little more than the cost of piping and a few small pumps and switches, Cohen’s team ran some PEX tubing through the detention pond and then around each dental exam chair, providing some radiant cooling for the staff without affecting the air temperature and cooling patients too much.
Lighting and Electrical Systems
David Nelson, AIA, of the lighting design firm David Nelson & Associates in Colorado, says that while lighting is likely to cost more on a green building, there are steps that can be taken to offset that.
Nelson cites the current market transition from fluorescent to more-expensive solid-state lighting, also known as LEDs (see “”), which avoid mercury, last longer, and deliver better light quality.
Green buildings often feature reduced overall lighting power density (LPD), with lower levels of ambient lighting made up for by task lighting at workstations. Reduced LPD also means reduced cooling load, which can reduce the size of the mechanical system.
However, Nelson points out that high-performing, energy-saving lighting designs often come with more sophisticated controls, and those controls are hard to commission. That, in turn, Nelson blames on a rapidly evolving field rife with consolidation and lacking standards and protocols. As an example, he says, “Let’s say you ask for a spreadsheet that shows what’s controlled on what zone and on what time;” you might get radically different forms from different manufacturers. You might specify a control system from a single company, but because of acquisitions by that company, its panels, stations, and switches might look as different from each other as the Three Stooges. You might specify a control system that you know works well, but it gets substituted with one that doesn’t perform as well. Or your Basis of Design written two years ago when a project began might not match up well with the controls being sold today for construction. Then, more complex systems require more training, adding initial costs paid to the supplier and for the operations staff. “Until we start standardizing, we are going to have challenges cost-wise,” says Nelson.
Nelson recommends several steps for delivering high-performing, reliable lighting systems at the most reasonable cost:
• Provide simple, manual-on/auto-off controls to as many spaces as possible.
• Get the remainder of the lighting on the simplest possible control system.
• Push to spend adequate time in design. Project timelines are getting squeezed, Nelson says, reducing design costs up front but causing cost overruns due to lack of coordination.
Nelson has found that surface reflectance can be a big issue in green projects that use lower-reflectance natural materials. “Psychology plays a huge role” in a successful lighting design, he says, noting that designs for gloomy days are worth paying attention to. That can make it challenging to reduce lighting power density.
Balancing good lighting and low energy consumption is a key focus, says Rumsey, who looks to use fewer luminaires to begin with by providing low ambient light levels supplemented by task lighting. “Suddenly it makes it much easier to pay for a daylight dimming system on the perimeter.”
Materials: No Added Cost for Green
Amanda Kaminsky, sustainable construction manager at The Durst Organization, a commercial owner and developer in New York City, says that Durst has made a priority of product performance, environmental performance, minimized health impact, and cost in its product selection, and in general does not pay a premium for materials that meet its requirements—although she acknowledges that the organization has a lot of buying power. If a manufacturer can’t meet one of its requirements, it will shop it around to other manufacturers and often get what it’s looking for.
The increasingly global supply chain for building materials has helped reduce costs, but it presents its own challenges, says Kaminsky. “Typically we try to source as locally as possible,” but with supplies of things like casework and wood flooring coming from all over the world, “we are still trying to understand and get a good handle on whether we can get a product that is of the same quality and same environmental performance from some of these other locations.”
Durst is willing to pay a bit more when there is a clear environmental benefit, says Kaminsky. For example, Forest Stewardship Council (FSC) certified wood comes with a cost premium for them, she says. The group is also paying a small premium for concrete masonry units with recycled-glass content that reduces portland cement—offering a real reduction in embodied energy.
On the other hand, she says that most other green products, such as low-VOC-emitting products, don’t carry a premium. That’s even the case with products that have a Health Product Declaration (HPD), which Durst has been asking its manufacturers for. “If any manufacturer tells us they cannot give us an HPD, we go to another manufacturer—and we don’t have to do that much,” she says.
Molotsky, of Brandywine Realty Trust, agrees that green products are available with no premium, but there may be some homework required. “Almost anything you’d want in the building—wallboard, cleaning chemicals, paper products, fixtures—is a no-cost add for higher-performance content,” he says. But, he notes, you have to ask for it. “The sales folks tend to believe that if people aren’t asking for sustainable products, they’re not interested.” That’s not to say that it’s a cinch for those on the specifying and purchasing side. “You or I can’t afford to spend a week looking at a 100 different paints to determine which have no VOCs [and] are of the same quality and have the same color palette.”
Teamwork and Goal-Setting
“A precursor to all this is the leadership and vision of the owner,” argues BNIM’s Lesniewski. “If they’re at the table saying this is a goal and priority of ours, it’s going to keep the team moving forward.”
To that end, having a shared goal is key. Simply put, Lesniewski says, it helps to determine the energy and water budgets for the project, and “the goal of the project is to make all of those work within the cost budget.” When that table is set and the team is on board, “really it comes down to the team just working through things and attacking the highest order first, and refining.”
Getting the contractor involved early is a key point, says Lesniewski. Like others with whom EBN spoke, she extolled the virtues of the integrated project delivery (IPD) model, in which the general contractor, architect, and owner form a legal relationship early in the design process, where there is shared risk and shared reward (see “”). A key benefit of that, says Lesniewski, is getting reliable cost information early in design. “Getting good conceptual design cost estimates is pretty tricky,” she says, but it’s “crucial” to making early design decisions that affect construction cost. Early involvement of a builder, or of a cost estimator who is on board with the project objectives, has a big impact.
Getting fair pricing
That same point is emphasized by Rumsey, who says that engineering a cost-saving system doesn’t always translate to savings in the construction budget—at least, not without some tenacity.
On a lab building in Lake Tahoe, California, Rumsey created a design with chilled beams and was able to eliminate a chiller—instead using chilled-water cooling tanks. “The cost estimate came back with a chiller even though there was no chiller in our design,” he told EBN. “I said to the contractor, ‘We don’t need the chiller,’ and he said, ‘No, you can’t do a lab building without a chiller.’” The chiller eventually came out, Rumsey says, but “the next time around, in the construction documents phase, we got a cost estimate, and there’s that chiller again!” He says the team “argued about it again,” eventually removing it for good.
On the same project, Rumsey says he looked carefully at the estimate for ductwork. Because of the chilled beams, the amount of ductwork on the project was about half of the normal amount. The cost estimate included a round number for ductwork that set off alarm bells for Rumsey. Asking the contractor about it, Rumsey says he was told, “That’s the number we’ve always used.”
Rumsey says it’s a pattern on green projects: cost estimates for green design come back high, sometimes due to inaccuracy, sometimes because the cost estimator isn’t familiar with the system. There’s also the phenomenon of a number being repeated enough times that it becomes true: Rumsey says he has seen excessively high numbers for more innovative systems like chilled beams, where the same number gets quoted enough times that it seems to become accepted as accurate. There’s also the factor of the contractor covering their risk and tending to price higher with unfamiliar systems. Again, the IPD model shines here in sharing risk and reward and in incentivizing project team members to make each other successful.
The contractor as a key link
“Educating contractors on what we’re trying to do and how to do it is an important part of a good green building,” says Rumsey. On a project where Rumsey designed larger-diameter water piping to reduce friction, he says the pipe fitters at first didn’t get the point. But, he says, once they understood that the pipe should be installed similar to a wastewater pipe, “they built it beautifully, and it was affordable.” Absent that discussion, Rumsey guesses the pipe fitters might not have followed the design.
Costs of LEED
The cost of pursuing LEED is a focal point in conversations about the cost of green, but many of those discussions get off on the wrong foot, conflating “soft” costs of LEED documentation with other design and construction costs.
“The cost of LEED is the money you send to USGBC and the LEED consultant who is doing the paperwork,” says Brockman. “Everything else you have to do is best practice, and you should do it whether you’re doing LEED or not,” he argues. Indeed, costs like commissioning and energy modeling are increasingly accepted as requisite to delivering a project that beats code and performs as designed, and those costs aren’t being pinned on LEED.
Brockman says that more of SERA’s projects pursue LEED when clients understand that only a fraction of the costs are fees to the U.S. Green Building Council. He says, however, that documentation costs for LEED projects are fairly static and that those fees become harder to justify on smaller projects, which Brockman defines as 70,000 ft2 and down.
“I don’t think we had a lot of complaints in terms of anything costing more because of LEED,” says Hernando Miranda of Soltierra, who works to deliver LEED Gold and Platinum certifications with no or minimal cost premium over LEED Silver.
Miranda pinpoints process and teamwork as the keys to delivering LEED with minimal added costs:
• Write tight specifications for key low-cost strategies like construction waste management and construction IAQ management.
• Monitor contractors and make sure you’re getting good data as you go.
• Work with a team motivated to beat the LEED target.
In the end, according to consultants like Miranda, the reality is that LEED documentation doesn’t get done for free. If it’s not being billed separately, designers are eating the costs or building them into their fees. For some projects, those costs are leading them to go for “LEED certifiable,” without the documentation, but that approach can easily lead to lower-quality results (see “”).
Getting Paid—And Having Fun
“Energy efficiency does not have to be expensive or hard; it just takes intelligent, creative solutions,” says Adam Cohen, paraphrasing Wolfgang Feist, the Passivhaus Institut founder.
Approaching each building with a fresh eye is key, agrees Mehlomakulu. Rather than relying on cookie-cutter systems that reduce design time and perceived risk, “It takes more time, skill and understanding to develop a design adapted to a specific building.” Successful firms have the experience to get to integrated solutions more quickly, but the added work still translates to a higher design fee. “Even though that can be more than offset by lower construction costs,” Mehlomakulu says that “the challenge that comes in is communicating the added value to owners and designers.”
“More and more, we negotiate fees based on the level of effort required, not as a percentage of construction cost,” says Shinn, referring to the conventional way of calculating fees. “We often make the point that ‘investment’ in higher design fees can result in lower construction and operational costs.”
Delivering high-performing projects on a budget is a good challenge, says Souza, who adds, “We were getting tired of hearing that green costs too much.” On the net-zero library project, she says, “It was fun” to work with the owner and builder. “You can do it,” Souza says, “but you have to be thoughtful about all the decisions.”