Low-emissivity (Low-E) coatings are applied to one or more glass surfaces, further improving the unit’s thermal performance by reflecting infrared energy (heat) while allowing visible light to pass through. Coating types, colors, and characteristics can be “tuned” or customized by the architect to achieve specific goals. These goals may be site-specific and based on the physical orientation of the building. For instance, in cooler climate zones, south-facing windows may call for a specific higher SHGC rating to increase heat gain during the winter months. Visible Transmittance (VT) may also be adjusted with low-E coatings. VT measures the amount of visible light transmitted, impacting daylighting and occupant comfort. Higher VT values indicate better natural lighting within the building. Depending on the type of building and needs of occupants, specifying VT can provide a creative option to satisfy occupant requirements. When needed, lower VT ratings are better suited to reduce natural lighting to avoid glare, provide privacy, or create a specific aesthetic for the interior.

Multifamily homes often face noise challenges, particularly in urban environments or areas near transportation hubs. IGUs can be designed to offer improved sound insulation by varying the thickness of the glass panes or using laminated glass in conjunction with the IGU. This provides enhanced acoustic control, improving occupant comfort and privacy, which is particularly important in densely populated housing developments.

IGUs are commonly used in curtain wall systems for multifamily projects. These systems allow for large expanses of glass that maximize natural light while maintaining high energy efficiency. Curtain walls with IGUs can be used in a rainscreen configuration to provide additional moisture protection for the building envelope. The rainscreen design helps keep water out by using a ventilated air cavity behind the facade material, preventing moisture penetration into the insulation layer and offering another way to help reduce the risk of mold or structural damage.

Value Engineering as a Path to Success

For some projects, architects may decide to employ the concept of value engineering and introduce multiple material types for windows to balance energy performance, budget, and aesthetic expectations. Value engineering is a common and successful approach to design when there are limitations on the project that must be observed. For instance, when the front facade of a multifamily project requires a more creative and contemporary design with large fenestration, narrow frames, and metallic finish, aluminum framed windows are likely the best and only solution. These public-facing choices may be cost-prohibitive to specify for the entire project, so more affordable vinyl windows may be used for discreet areas, such as the back of the building. While both materials can deliver relatively strong energy efficiency, durability, and performance attributes, vinyl frames are not structurally capable of supporting the weight of larger glass systems, which is not an issue for extruded aluminum frames, even with thermal breaks.

The value engineering approach is an important tool when trying to meet overall building performance goals, for instance in California’s Title 24 requirements, where “trade-offs” are allowed between building components.

Photo courtesy of All Weather Architectural Aluminum

Trends indicated buyers and renters are looking for increased square footage inside private spaces to allow for work-from-home and entertaining.

A SHIFT IN DESIGN

Design innovations in multifamily housing are evolving both inside and out. Modern buyers and renters are becoming more aware of how their living space impacts their health, wellness, emotional balance, and social interactions. To this end, buyers are starting to seek out properties with alternate floor space plans, biophilic accents, and a different focus on the type and style of amenities. For the architect, these changes in attitude about the dwelling space are driving design and material specifications in the multifamily market.

The Work-From-Home Occupant

Modern trends point to a desire for more space within the home, and the efforts include finding better ways to use spaces in the structure. Even before the Covid-19 pandemic, the home office was becoming an oft-required staple for renters and buyers. Since the pandemic, many companies have found an increase in productivity from employees who work from home, and an opportunity to scale back on office space by offering either fully remote or hybrid working environments. A recent survey by the Bureau of Labor Statistics found that around 27% of the U.S. workforce was working remotely at least part-time, and information from the Pew Research Center highlights that about a third of workers with jobs that can be done remotely are working from home all of the time, up from only 7% before the pandemic.

Multifamily units are the ideal solution for a work-from-home generation hoping to downsize, skip the commute, and simplify their lifestyle. The challenge resides in trying to accommodate this new lifestyle, as buyers are prioritizing new and different aspects of interest in a multifamily home.

First, a dedicated workspace or ideally a separate home office is a must for many. Teleconference calls from the kitchen table are a thing of the past. Productivity and privacy are fundamental for work-from-home occupants, yet to incorporate this into a standard design can be a creative challenge for the architect. Home offices must meet the same egress requirements as bedrooms per the International Residential Code (IRC), however, work areas without a door may provide a design solution. A flexible home environment may include movable partitions, curtained areas, or line-of-sight changes that can provide privacy but also allow easy access to the rest of the living space.

Another option to increase per-unit square footage is to simply reduce the overall number of units in a project. Although counterintuitive to the idea that more units equals higher returns, building owners have found that reducing the number of units can be a windfall financially. Larger floorplans can demand a higher premium per square foot, meaning the overall average price of units will rise. Fewer units can increase the total amount of square footage per project. Fewer units also put less demand on parking, heating and cooling systems, and amenities.

To increase square footage per unit, a final option is to forgo some of the traditional communal spaces and amenities offered. This approach follows recent trends in multifamily building that suggest occupants are less interested in sharing spaces outside with their neighbors, and that people tend to socialize more in private individual units. While a dedicated gym or workout area is still a popular attribute for buyers, spaces like conference rooms, lounges, games rooms, and communal kitchens tend to be underused. A more common solution is to create a separate center for these amenities, though. A stand-alone amenities center can prove ideal to maximize unit capacity and help manage noise and activity levels within the multifamily complex. This approach can facilitate more popular trends for occupants that include pet-friendly features like pet washing stations or fenced off-leash areas.

Selecting alternative amenities can also be a way to reduce overall energy use and maintenance for the building. Instead of installing a rooftop swimming pool or barbecue area, for example, switch to a living green roof offering residents a community garden. Creative alternatives can drastically reduce energy and water use, minimize maintenance, and attract occupants who are looking for a more non-traditional approach to renting or homeownership.

Photo courtesy of All Weather Architectural Aluminum

In the multifamily environment one of the key methods of incorporating a more biophilic design is to invite more natural daylight into the living spaces.

Photography by Robert Tsai; courtesy of HKS

Access to the outside of the building through large operable fenestration or multi-panel sliding doors enables occupants to connect better with fresh air and daylight.

Designing for Daylight

Whether as a response to the work-from-home trend or simply as a desire to incorporate nature and light into the home, biophilic design is becoming more prevalent in multifamily projects. Biophilic design is the incorporation of nature or natural elements into the built environment. The result is a better connection between people and the planet, which has been shown to improve mood, concentration, health, productivity, and even sleep cycles.

In the multifamily environment, one of the key methods of incorporating a more biophilic design is to invite more natural daylight into the living spaces. Thomas Ehret, Regional Sales Representative for All Weather Architectural Windows and Doors, has noted this shift in the priorities of buyers and renters when it comes to multifamily dwellings and nature or the outdoors. “The trend is really going towards larger windows, bigger views, and more light coming into the home,” says Ehret. “Everybody wants thin sight lines and more openings for glass. From the inside, it means better views and lots of light, from the outside it can work to express more of an architectural design for a project.”

Requesting larger windows and more light is not a simple design alteration, and comes with consequences, especially when trying to improve building energy performance. “Larger windows offer better buyer appeal and rental appeal for the end user who’s going to be living in that particular apartment or townhouse, but the challenge is to attain the same energy performance capabilities of smaller fenestration units,” Ehret says.

Expansive views require thinner frames to allow for more glass. Extruded aluminum frames are ideal for this application. Aluminum is strong enough to incorporate multi-pane windows or IGUs with minimal framing requirements. With the advancements in thermal breaks and warm-edge spacers, modern metal framed windows can easily satisfy U-rating requirements.

Access to fresh air and the outdoors is also trending in multifamily design, especially for units with a patio, balcony or terrace. According to Ehret, French doors and sliding doors with multiple panels remain of strong interest to potential buyers. “Multi-slide doors systems are really popular right now. Buyers are starting to gravitate to the ability to open the whole wall and bring the outside in, especially on the ground floor if there is a courtyard with greenery. It’s very soothing and I think it reminds them of a Hawai’i trip,” Ehret says.