Photo: Chip Allen Photography

Innovations in technology, manufacturing, and automation enable architects to meet the new expectations of homebuyers in the multifamily market.

Innovations in the multifamily sector of building design and construction include a generation of proven fenestration systems serving novel envelope systems and facade designs that combine energy efficiency and long-term performance with the market-pleasing trend toward more indoor-outdoor experiences. This course closely looks at performance-boosting building approaches developed and put into practice recently with an emphasis on fenestration techniques that focus on thermally broken aluminum windows, doors, and sliding and multi-slide openings.

BUILDING FOR MULTIFAMILY USE – A CHANGING LANDSCAPE

Multifamily building has gone through several significant changes in the past few years. As more occupants turn to work-from-home options, the demands of individual living spaces have moved from larger communal areas to more personal spaces. Expectations for increased comfort, healthy living spaces, clean air, access to natural light, and operable windows have also increased as occupants are spending more time indoors. Building technology has advanced and some become automated, creating more consistent, resilient, and repeatable delivery of building components. Windows, doors, and wall systems can now be manufactured with efficient streamlined production, delivery, and installation.

Leading the long list of new innovations in multifamily construction is building performance, which has progressed significantly in terms of innovation, especially in the design and construction of the shell or building envelope. Improved fenestration options, glazing, rain screen technology, thermal breaks, and water management strategies now can work in harmony to create multifamily homes that are durable, healthy, energy-efficient, and aesthetically creative.

Photo courtesy of All Weather Architectural Aluminum

Low-rise multifamily projects are increasingly focused on affordability for occupants, which includes reducing energy costs through performance improvements.

A BOOST IN PERFORMANCE

Of all the latest advancements in low-rise multifamily construction, the design and integration of performance-improving building components is strikingly significant. With an increased awareness of electrical generation and the link to mitigating climate change in terms of carbon emissions, reducing the amount of energy used to heat, cool, and light residential spaces is becoming a focal point across the board. However, it is important to remember that while promoting a cleaner and more sustainable environment outside the home is critical, for many homeowners and renters poorly insulated or shabbily designed homes have a much more immediate impact.

While some architects have the opportunity to consider and design high-end projects such as those catering to luxury townhome developers, most multifamily projects in the next 10 years will consist of low-rise buildings in an effort to address the current housing crisis. These buildings will likely be targeted at working-class families, and this makes sense considering the growth of affordable housing projects in the U.S., as well. Building performance directly impacts the health and well-being of occupants through poor indoor air quality, water intrusion, and overall comfort. A poorly designed and constructed home also carries the consequence of a monthly pain point of high energy costs for the homeowner.

According to recent figures from the National Association of Home Builders (NAHB), over 43 million Americans live in multifamily housing or approximately 31 percent of the total housing stock in the United States.¹ Given increasing urbanization, inflation, financial challenges for first-time home buyers, and high interest rates cooling the single-family home market, this number is expected to rise over the next few years. Most occupants are renters and a disproportionate number are poor, minority, single parents with children.

When looking at the existing housing stock, a study by the American Council for an Energy-Efficient Economy (ACEEE) found that improvements in energy efficiency could reduce multifamily building energy use by around 15-30%, especially through targeted interventions such as upgrading HVAC systems, improving insulation, and enhancing window performance. This level of reduction in energy use is significant, especially for low-income multifamily, non-white, and Hispanic households who disproportionally experience high energy burdens, and use a large share of their income to pay for energy bills. Nearly half of low-income multifamily households experience an energy burden greater than 6% as compared to 2% for non-low-income households. Research by ACEEE uncovered that electric end uses, for example, space heaters or mobile air conditioning units, are proving to be the leading cause of high energy consumption for low-income, non-white, and Hispanic multifamily households.

For new multifamily construction and retrofit projects, a focus on building performance can impact both occupants and building owners. NAHB has also noted that today’s potential homeowners are environmentally aware and have an increased interest in homes that promote sustainable design through carbon reduction and overall lowered energy use. The return on investment for upgrading the performance of buildings through improved materials and design can be relatively rapid as these units often can be offered at a premium to an eager market.

Photo by Brian Gassel; courtesy of Niles Bolton Associates

The natural properties of aluminum allow the metal to be used in a variety of high-performance and aesthetically interesting fenestration options.

High Expectations for Fenestration

Fenestration has proven to be a critical element in modern multifamily construction with many expectations for performance, operability, and aesthetics. Balancing the design and performance goals of a project can be a challenge but also rewarding. Modern low-rise, or buildings under five stories tall, increasingly seem to require the best of all worlds: expansive views, natural light, interesting exteriors, and energy efficiency─all on a conservative construction budget.

For the architect, the specification of the material type of frames can have a significant impact on the project in terms of both cost and performance.

Today’s choices for fenestration include aluminum, vinyl, wood, fiberglass, and composite material. Of these, aluminum, vinyl, and wood capture most of the market share. The pros and cons of each material type need to be weighed against the overall goals of the project, budget, and how well each type integrates with the building envelope.

Aluminum frames are widely used in fenestration for multifamily housing due to their durability, lightweight material, and strength. One of the primary advantages of aluminum is its ability to support larger glass panes while maintaining a slim profile that allows for improved line-of-sight and maximized natural light. Aluminum is resistant to corrosion, can be extruded into custom shapes and lengths, can be painted or anodized to match any color, and is very low maintenance. However, aluminum has high thermal conductivity, meaning it easily transfers heat and cold, making it less energy-efficient compared to other materials. To address this, aluminum frames often include thermal breaks—plastic sections within the frame that help reduce the flow of heat.