Often, the embodied energy and carbon footprint of the building materials takes a backseat to the energy profile during the operations phase. “Architects are improving the energy-efficient performance of our buildings across the spectrum,” says Gita Nandan, R.A., an architect and founder of the firm thread collective, New York City. “The DOE has concluded that nonresidential buildings in the United States account for almost three-quarters of domestic electricity use and more than a third of natural gas demand, totaling about 9 percent of greenhouse gas production globally.”

With that in mind, says Nandan, many architects are using certification to PHIUS 2015: Passive Building Standard – North America, supported through a DOE grant and overseen by the Passive House Institute US (PHIUS), which focuses on achieving low-energy-use buildings. This new focus means that materials like polyiso CI insulation and non-metallic window frames are in greater demand. Passive House requires thermal-bridge-free designs and highly insulated enclosures, says Nandan. In addition, many Passive House designs utilize VRF air-conditioning systems, thanks to their high efficiencies and the ability to provide local or personal comfort control. (See ViewHaus case study, below.)

In a typical VRF system, conditioned refrigerant is supplied from an outdoor unit to indoor units, sometimes called air-handling units or AHUs. The space-conditioning requirements dictate how much refrigerant the outdoor unit delivers to the indoor units—explaining the name, variable refrigerant flow—varying the compressor speed to match the cooling or heating requirements. That means comfort controlled locally within the zone, which contributes to the high efficiency levels of ductless and VRF systems. “Using a two-pipe simultaneous cooling and heating system provides an enhanced personalized comfort experience for occupants,” adds Mitsubishi Electric’s Miskewicz. “This also delivers an energy-efficient operating experience to the building owner.”

Recent advances in the technology have made VRF even more adaptable and efficient, adds Miskewicz. VRF systems can be applied to mixed-use, multifamily and office buildings, for example, including ducted and ductless indoor units which can be mounted on the wall, floor, or ceiling. They can integrate heat-pump and heat-recovery systems with air and water sources, too. The ACHR News hailed these large systems as user-friendly and compact, opening up options for space-restricted locations and “giving the ductless a crossover application in the commercial world as well.”

Miskewicz considers this a game-changer because, he says, architects “can design around their vision rather than the constraints of traditional or conventional HVAC systems.” Architects like JZA D’s Zinder agree, saying, “We now use split systems in lots of buildings, where the VRF technology gave those projects added flexibility—increasing usable space in walls and ceilings, for example—and the benefit of controlling HVAC levels in certain spaces of the buildings that were not in use.” The architect adds that these benefits are valuable for Passive House certifications, which are increasingly a goal for his firm and many others.

In fact, as emerging trends addressed by these innovations influence construction-market dynamics, architects see more use of these products to build green. To demonstrate that the approaches work, many are using performance verification techniques to provide transparency on environmental impact. Project case studies also help underscore the benefits of innovations in wood, vinyl, polyiso, and more.

CASE STUDY: A SOUND SOLUTION FOR NEW FLOORING

In a damp and humid locale like waterfront Florida, green building takes on additional dimensions. A product can’t be truly sustainable in this type of environment if it’s susceptible to mold, decay, and cracking, say architects with expertise in multifamily developments. For these reasons, longevity and air quality were prime concerns for developers Donald Trump and Dezer Properties in their work on the Trump International Sonesta Beach Resort in Sunny Isles, Florida. When it came time to prepare the floor assemblies, their architectural team had to find a way to address these issues as well as noise abatement—this is a 355-room luxury resort, after all.

Photo courtesy of MP Global Products, LLC

In the end, the specifiers identified their best choice: a recycled-fiber acoustic underlayment. A unique subfloor option, the roll material would help absorb sound impact, suppress the effect of subfloor cracking, and deliver a LEED-compliant solution certified by SCS Global Services to contain 100 percent post-industrial fibers. The relatively thin pad also provided some flexibility: It could be used with hardwood or engineered wood floors as well as with ceramic flooring materials needed in some areas.

For the purposes of the Trump International Sonesta, this type of underlayment fit the bill, according to Angel Acosta, the construction project manager with Trump Grande Ocean Resort and Residences. Acosta notes that the underlayment was easy to install, cost effective, and met all the code requirements of the jurisdiction. In addition, the underlayment is manufactured in a high-temperature process that kills bacteria and fungus before installation; an antimicrobial additive inhibits subsequent mold growth, helping ensure that the final construction would reduce microbial levels in the subtropic location. The recycled-fiber acoustic underlayments also exceed the most rigorous product emissions and VOC tests, contributing to improved project indoor environmental quality (IEQ).

Of equal importance to the Trump Sonesta’s developers, the recycled-fiber underlayment enhances the visitor experience. Constructed of randomly air-laid filaments that create a capillary effect, the thin pads can wick subfloor or incidental perimeter moisture and disperse it through the pad. Moderate amounts of moisture eventually dissipate over time by perimeter or subfloor evaporation—provided the source of water or leak is stopped, of course. This capability helps inhibit mold and mildew, helping improve local IEQ while effectively cushioning the floor and providing enough elasticity to resist the transfer of concrete subfloor cracks and other imperfections in level. As an added benefit, this cushioning also absorbs impact sound, facilitating the noise abatement required of a high-end resort structure.