Navigating Green Design
Over the last 30 years there has been a growing public awareness of climate change and standards created to manage it. Buildings in their design, construction, and occupancy, contribute to the problem, depending on location. For example, currently, buildings account for 71% of New York City’s greenhouse gas emissions. So, when architects design buildings and spaces there are several established standards to follow. How would you choose one or several, why, and for which project types? We will look at four of the dominant standards.
The Design Standards: LEED, Living Building Challenge, Passive House, WELL (LEED, LBC, PH, and WELL)
There are similarities and differences. Both LEED and PH have criteria that involve user health and comfort. LEED covers materials and fixture selection while PH focuses on providing filtered fresh ventilation to every space. Also, meeting the PH thermal comfort criteria are fundamental aspects of certification. Both WELL and LEED involve healthy, sustainable construction practices and ongoing building operations after a building is turned over. WELL certification focuses on people's health and wellness, while LEED is a certification that focuses on environmental impact and sustainability. Where LEED goals could be summarized as “Do less harm,” the Living Building Challenge tagline might be “Fix the damage.”
All organizations are focused on how buildings can be more efficient and less reliant on fossil fuels, and focus on conserving other finite and at-risk environmental resources. All have missions influenced by global climate change and are holistic voluntary third-party green building certifications. Each provides measurable strategies and tactics to improve the design, construction, maintenance, and operation of the built environment.
In summary, these certifications focus on:
LEED – Currently the most widely used, optimizes energy performance, reducing carbon footprints, preventing pollution and including sustainable water management practices, among many other sustainable standards.
LBC -- Goes beyond just sustainability, low energy, and healthy, to focus on doing more good than less bad for the environment and people, net energy positive, geared to eliminate toxins used in building products.
PH – A rigorous energy reduction strategy within a quantifiable human comfort range, net-zero ready, filtered fresh air to every space, points transferrable to LEED.
WELL – The minimum standard to achieve a healthy building in addition to a comfortable one (see PH), significantly decreases the size of the mechanical loads and will reduce your energy bill thus a mechanical system with an ROI.
LEED - Leadership in Energy and Environmental Design
LBC - Living Building Challenge
PH - Passive House
WELL - International Well Building Council
How to Choose?
A closer look reveals some of the possible reasons for choosing one standard over another or in addition to another. The LEED certification program is currently the most widely used green building rating system globally. LBC certification is the most comprehensive and forces stakeholders to evaluate all aspects of green building design. PH has strict performance standards, either you achieve the standard, or you don’t. The high-performance building enclosure goal for PH features robust insulation and thermal bridge mitigation to decrease, or in some cases, eliminate dependency on mechanical heating and cooling systems. WELL is administered by the same organization that administers LEED, the International Well Building Council, which helps projects more easily achieve dual certification.
Cost
The biggest challenge to adopting any of the above green design strategies tends to be the first cost associated with selecting materials and building systems that meet the rating system criteria. This is usually offset by the energy savings or increased human productivity. However, many clients want to see short payback periods as low as five years, which may not be easy to achieve or calculate under some of the programs.
To offset first cost premiums, some municipalities are developing codes or other legislation that require green strategies to be undertaken. In many cases, the municipalities develop energy performance criteria, but do not require specific rating systems to be used. In other cases, they do require certain codes or rating systems to be used.
In the case of PH, the energy savings can be significant enough year-over-year to have a relatively short payback. For a single-family home, this might bring the cost in line with the average cost of a new built-to-code house.
Clear Choice for a Single-Family Home
In the end, selecting a certification program or programs depends on your user functions and/or project type, location, and your client’s goals. To achieve a Healthy Green Home the choice is Passive House combined with WELL for the most energy efficient and quantifiably healthier indoor environment. (Please see the Den Road Residence.)