Today, “High-Performance” generally refers to: Maximum Energy Efficiency; Physical and Emotional Comfort; Healthy IAQ; Resilience; and ultimately, Zero Net Energy; Zero Net Carbon. The Passive House Planning Package (PHPP) and the recently introduced PH Ribbon (integrates embodied carbon) make it possible to deliver the owner’s targets for high-performance. The three-legged stool of Early planning, Envelope first, and Aspirational goals are critical to achieving desired performance on time and on budget with minimal surprises.
Early planning — You may remember the MacLeamy Curve from an earlier EpiPHany. Effort Curve When you select your team and invest in planning, modeling, and budgeting early, you enable maximum functional capabilities with minimal cost.
- Owners/developers identify and involve the integrated team of professionals: Architect/designer, major consultants & subs, builder/contractor. All team members should be performance advocates with the necessary skills and experience.
- The owner/developer and the integrated team participate in creating a comprehensive and detailed Owners Project Requirements (OPR) that sets performance goals for all relevant aspects of the project. Agreement on these specific goals ensures team alignment and efficient collaboration.
Envelope first — The airtightness, climate specific strategic insulation, and detailed thermal bridge analysis associated with Passive House are foundational to achieving high-performance buildings. Making decisions and developing specifications for the envelope first provides significant benefits for the project.
- A high-performance envelope dramatically reduces unplanned infiltration of airborne allergens and pollutants (including smoke from wildfires) and provides control of continuous fresh air, indoor air quality, moisture content and other factors, as well as enabling the use of smaller mechanical systems.
- Comprehensive design and specifications for the envelope provides information that will simplify and clarify the work of consulting engineers, sub-contractors, suppliers, and laborers. This clarity and alignment reduce problems/conflicts and avoid the associated premiums.
- Resilience to extreme heat or cold, fire, smoke/air pollutants, and power outages has become recognized as more critical in recent years due to climate change. A high-performance envelope is the top priority for achieving resiliency. See previous EpiPHany on Enclosure/Resilience.
Aspirational goals: When contemplating performance goals for a new building/project, or for a renovation or retrofit, we often limit our thinking to a list of performance related tactics or the expected budget. It is far more effective to approach from a big picture perspective and consider what is potentially possible.
- Creating an aspirational OPR, as described above in “Early planning”, provides a much better understanding of the goals you expect to achieve — and the highest probability of achieving them. Because it is early, design modifications will be possible with minimal increased investment.
- If the realities of time and budget require modifications and/or the reduction of some goals, the project will still achieve a systematic level of performance that is much closer to the original targets. The alternative, a tactic-by-tactic approach to performance (add solar, and/or better windows, and or more insulation, and/or etc.) is not likely to deliver a comparable level of balanced performance.
These three tips will help you identify and achieve the high-performance goals appropriate for your project. They will also reduce false starts and surprises, increase collaboration, and minimize additional investment required to reach desired levels of performance. Achievable high-performance is the logically appropriate baseline.
Author: Jay Gentry