Senior living buildings contribute a significant amount of carbon during their construction and as they operate. With currently more than 2.9 million existing units (not including skilled nursing) in more than 22,000 communities—and thousands of new units being added every year—this large real estate footprint translates to an equally significant carbon footprint.
Using metrics from the multifamily housing industry that examines emissions over the life of buildings, the senior living industry is responsible for approximately 3.8 billion metric tons of carbon dioxide emissions—the equivalent of 25 coal-fired power plants running for 40 years. Buildings’ operations and the embodied carbon in building materials, which is the amount of carbon released in the production of the material and its transport to the site, further impact climate change and account for 40 percent of the world’s carbon emissions.
This creates an opportunity for the senior living sector to make a large contribution to reduce carbon emissions, while spending less money over the lifecycle of buildings and reducing financial risk. Design strategies, such as more robust insulation at exterior walls and high-quality glazing, that are less energy dependent and more resilient may require an upfront cost but will save money over the course of a building’s life cycle.
Additionally, regulatory changes are demanding better performing buildings and more robust disaster preparedness plans. When disaster preparedness is designed into the building from the beginning, recovery costs less. Recently, California building codes were changed to require all new multifamily housing under three stories, including senior living units classified as housing under the building code, to be powered by renewable energy such as solar.
Through strategic approaches to building and landscape design, the senior living industry can reduce energy usage and emissions with the goal of creating resilient and healthy communities that produce as much energy as they consume.
Building strategies
Utilizing efficient building systems and a high performing exterior envelope can reduce the amount of energy and resources a building uses and allow it to more easily offset the remaining energy loads with on-site renewable sources. In a net zero energy building, the energy consumed by a building is roughly equal to the amount of renewable energy created on the building site.
The performance of the roof and exterior skin of the building, including glazing and solid wall areas, has a direct effect on energy usage and the comfort of residents. A poorly performing skin can cause interior temperature fluctuations and uncomfortable high or low temperatures depending on the exterior temperature and the building’s solar orientation. Measures to increase performance, many code-required, include highly insulative materials, windows, and walls and robust continuous air barriers to reduce air leakage and improve envelope vapor control.
Heating and cooling demands are typically higher in senior living than in other types of housing because residents have less tolerance for temperature fluctuations. Radiant cooling is likely to be a more effective and efficient solution for buildings in many climate types but brings with it some additional complexity for interior humidity control. These systems actively cool the floor slab or ceiling panels to provide comfort cooling within the space and are often combined with dedicated outdoor air systems, which provide required ventilation air and humidity control.
Heat pumps are a good solution for both building heating and hot water heating because they are extremely efficient. Instead of generating heat, they only move it from one place to another by
pulling heat from exterior air or ground and pushing it through refrigerant into interior spaces for heat or into tanks to heat water. They can also be used in reverse to cool a space.
Once a community’s energy demands are reduced, renewable energy sources such as solar panels and wind turbines can be included on-site to produce the remaining amount of energy demand. Appliances and building systems such as heating and cooling can be electrified so that natural gas is eliminated to reduce cost, risk, and carbon footprint. Solar panels are decreasing rapidly in cost and increasing in efficiency. For a typical senior living community, payback on solar panels ranges from 5-10 years, depending on incentives and tax write-offs.
As a partner to solar panels, battery storage offers the ability to store excess electricity generated by solar panels, providing a constant, reliable electricity source during non-sunny hours. Battery backup also lessens the chance of interrupted power during a climate event when the main electrical grid goes down. Batteries are typically attached to walls and located in garage or basement spaces or in other back-of-house building support spaces.
Another option, wind turbines, may be used as a supplemental energy system because wind speed and duration are variable. While large turbines are more appropriate in an onshore or offshore wind farm or when a community is sited on a large parcel, smaller-scale ones are quickly coming to market for residential uses. These models, which use a vertical axis turbine (one that has blades oriented vertically instead of horizontal to the turbine structure) and can be roof-mounted, cost as low as $5,000 and generate as much as 2,000 kilowatt hours of energy a year, or 25 percent of the energy requirements of a single-family home.
A secondary goal within the building is to reduce the amount of embodied carbon inherent in building materials during new construction and renovation. Considerations should include where a material is sourced, the amount of energy and resources it takes to make the product, and how the product is transported to the site. Materials that have high embodied carbon, such as steel and concrete, should be avoided when possible.
For example, the production of cement, the main ingredient in concrete, accounts for 8 percent of the world’s carbon emissions. Wood structures, when sourced from Forest Stewardship Council certified forests, are a low carbon option for the building structure. Heavy timber construction is now being tested as a low-carbon option for high-rise buildings.
Landscape design
The site’s landscape design can be a powerful tool to reduce the effects of increasing global temperatures while also increasing resident well-being. Strategies such as using drought-tolerant plantings, harvesting rainwater and greywater, and adding mulch to reduce irrigation demands in the hottest months can save considerable water costs.
Rainwater capture systems can be easily added onsite as part of a minor renovation by rerouting gutters to water containment devices, which can then be used for irrigation. Greywater systems are simplest to achieve when connected to residential washing machines at initial construction but can also be done as part of a moderate renovation. In these systems, diverters are connected to the waste lines of the washing machine and gravity or pumps pull the water to storage cisterns, which are then connected to the irrigation system.
With a looming increase in the frequency and duration of heat waves and a resident population especially susceptible to high temperatures, it’s important to strategically place greenspace and trees to reduce perceived temperature. Hardscapes accumulate and store heat during the day, radiating that heat out as the ambient air cools. Adding trees for shade and replacing hardscape with planting, especially on the west side of buildings can mitigate stored heat in buildings. Green roofs can also help to reduce temperatures and capture rainwater.
Healthier future
The additional cost for these strategies ranges from a 5-15 percent premium in upfront costs compared to standard approaches, dependent on complexity of the system, location, and size. Tax incentives may help reduce this additional cost. However, it’s important to note that given these upfront costs, the cost of the building over the entire life cycle is typically much lower than conventional approaches, and monthly utility costs are a fraction of conventional approaches.
When factoring in the number of potential extreme climate events, the total cost of owning and operating senior living communities that are net zero will be exponentially lower because these approaches create a more resilient building and positively impact risk avoidance for responding to climate events. For example, if a community has better building envelope performance, the temperature in the building changes at a slower rate during a power outage or an extreme heat wave. This not only puts less environmental stress on residents and staff, it also lessens the stress on the building’s systems to maintain occupant comfort.
Resilient design strategies can help owners save money over the life of the building, make for a more marketable community, and create a healthier environment that’s more able to adapt to a changing climate. Many of these strategies are already being implemented in other housing types, including multifamily and affordable housing. Ultimately, the senior living industry has a moral responsibility to provide not only residents with a healthy, resilient environment, but also our children, grandchildren, and all future generations.
Alexis Denton, an architect and gerontologist, is a senior living strategist at SmithGroup (San Francisco). She can be reached at [email protected]. Stet Sanborn is a mechanical engineer at SmithGroup (San Francisco). He can be reached at [email protected].
