Sustainable Design Thinking and Acoustics: Where Are We Now?

Throughout my career journey from architecture to acoustics consulting, I have been dedicated to understanding the environmental impacts of building construction. It has been long known that the AEC industry is a big contributor, responsible for a whopping 40% of global CO2 emissions annually (source: https://architecture2030.org/).

In addition to the AEC industry targets to reduce our impact (such as the Architecture 2030 Challenge and AIA 2030 Commitment Program), there are also externally driven legislative pressures and incentives that are driving these targeted goals. Many states in the U.S. are rapidly adopting more stringent energy efficiency requirements into code, with some targeting a reduction in greenhouse gas emissions by 50% by 2030 and net-zero by 2050. The Inflation Reduction Act provides several financial incentives for electrification, renewable energy, and energy efficiency measures.  

With these big challenges, where does the practice of acoustics fit in? Well, the full picture of sustainability includes not only environmental health, but occupant health and wellness. Spaces with thoughtful acoustic design across multiple project types are proven to help increase sleep quality and the ability to concentrate while also reducing stress (and other benefits!). This is why you see acoustic language in several green building rating systems – such as LEED, WELL, Passive House (International), Fitwel, and Green Globes. Ultimately, this supports environmental goals as well, because buildings that perform well for their occupants are more likely to be maintained and updated for future generations rather than demolished and replaced.

The best way to make sure that a building is both environmentally responsible and supportive of occupant health is to incorporate these needs early in the design process. Below are some broad ideas into how good acoustics can affect other sustainable building strategies, and what things you should be thinking about in your next projects:

Operational Energy – This is the energy that is required to power and condition buildings. This accounts for 27% of a building’s emissions. The current strategies to address this involve making the new and existing building stock as energy efficient as possible, and eliminating fossil fuel usage in favor of renewable energy which can be implemented through electrification of building systems.   

• To improve the energy efficiency of buildings, they will need to be well-insulated and airtight. In general, the less air transfer happens through a building envelope, the better it will also be at blocking sound. Many types of insulation – but not all – also provide acoustic benefit.
• Heat pumps are currently a large part of the strategy for sustainable building conditioning. While these systems can be quiet, they still introduce noise-making components (such as fan noise and compressor noise) into the interior and exterior of buildings, and should be carefully evaluated from a noise-perspective. Ground-source heat pumps are typically quieter than air-source heat pumps, since they typically have fewer noise-making components.
• Switching from fossil fuel to renewable sources is of critical importance, but we need to think about the noise impact of these sources. Wind turbine noise is a classic example, and there must be a comprehensive study of the noise when planning these projects. Did you know that even solar energy generation can produce noise?

Embodied Energy – This is the energy that is required to construct or renovate a building, including the energy for the extraction/fabrication/transportation of building materials, energy consumed by the construction process, and energy required to dismantle and dispose of a building at its end of life. This accounts for 13% of buildings’ emissions. The current strategies to address this include the selection of more environmentally responsible materials, improving manufacturing processes, and reducing transport distances.

• In general, a material’s ability to block unwanted sound is related to its mass. Concrete, one of the dirtiest materials from an emissions standpoint, can be important for acoustic reasons. Sometimes acousticians need to ask for more concrete than originally planned, for sound isolation purposes, which very clearly made me think about my own impact in environmental responsibility. The need for concrete can even show up in mass timber projects. To address this, we are staying abreast of improvements to concrete formulation, and can help optimize the amount of material needed to balance acoustic and material needs.
• Similar to above, in cavity construction, an acoustician may need to require extra layers of material on walls/floor ceiling assemblies than originally planned, for sound isolation reasons. Industry-wide, we are still unsure of the acoustic effectiveness of lighter-weight wallboard products, but are paying close attention to this as new information becomes available.
• In addition to the material required to block sound, we often require significant amounts of material dedicated to sound absorption. This obviously goes beyond the amount of material needed to put up a building, but, because these materials make a huge contribution to occupant comfort and satisfaction, they should not be considered as extraneous. Thankfully, there are lots of products available that are conscious of environmental impact and human health needs.

This overview demonstrates the complexity of needs that a project should consider from an acoustical perspective, and our responsibility as acousticians to keep up with the progress of developments in sustainable materials and construction. We are experts at helping our clients balance a variety of project needs, and tackling the climate crisis is something that we are in on together.