Environments for Aging - Spring 2020 - 21

COMMUNITY

Aiming for net zero

Building and landscape design strategies can reduce energy usage and emissions and create
resilient communities By Alexis Denton and Stet Sanborn

enior living buildings contribute a
significant amount of carbon to the
environment during their construction
and ongoing operations. With currently more
than 2.9 million existing residential units (not
including skilled nursing) in more than 22,000
communities, plus thousands of new units
being added every year, this large real estate
footprint translates to an equally significant
carbon footprint.

emissions with the goal of creating resilient
and healthy communities. With all of this
in mind, it's possible to see a future where
senior living communities might produce as
much energy as they consume-reaching
what's termed "net zero," where the energy
consumed by a building is roughly equal to
the amount of renewable energy created on
the building site. To achieve this, there are
existing products and strategies available

of generating heat, they only move it from
one place to another by pulling heat from the
exterior air or ground and pushing it through
refrigerant into interior spaces to warm rooms
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 provide the remaining amount

Based on metrics developed by the state
of Washington for multifamily housing, senior
living's estimated emissions over the life of
buildings may be 3.8 billion metric tons of carbon dioxide or higher. This is equivalent to 25
coal-fired power plants running for 40 years.
It's likely that the actual numbers are higher
because senior living is more energy intensive
than typical multifamily housing. In addition
to the emissions of existing housing stock,
thousands of new units are added every year,
further increasing the industry's impact.
Conversely, this reality also creates an
opportunity for the senior living sector to substantially reduce carbon emissions, all while
potentially spending less money over the life
cycle of buildings and reducing financial risk.
For example, design strategies that are less
energy dependent and more resilient, such
as more robust insulation at exterior walls and
high-quality glazing, 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.
For example, California building codes were
recently 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. The idea behind such
efforts is that when disaster preparedness is
designed into the building from the beginning,
recovery costs less.
Through strategic approaches to building and landscape design, the senior living
industry can reduce energy usage and

now that can be used in the design of buildings and their surrounding landscapes.

of energy required. 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 rapidly decreasing in cost and
increasing in efficiency. For a typical senior
living community, payback on solar panels
ranges from five to 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 is using wind turbines 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, start at a cost
of $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

Building strategies
Utilizing efficient building systems and a highperforming exterior envelope can reduce the
amount of energy and resources a building
uses and allow a community to more easily
offset its remaining energy loads with on-site
renewable sources. 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

Spring 2020 * EFAmagazine.com

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Environments for Aging - Spring 2020

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