PhiusCon Pre-Conference: Building Science Rocks in Tarrytown!

There will be something for everyone at PhiusCon 2021 Pre-Conference, a great way to warm up for the PhiusCon Core Conference–all in Tarrytown, New York.

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Prudence Ferreira

Pre-conference starts on Tuesday, Oct. 12, with a trio of diverse sessions. One of our most highly anticipated sessions is “Phius Critical Path for Large-Scale Buildings” presented by BR+A Consulting Engineers Senior Associate and Phius Board Member Prudence Ferreira. With more than a decade of passive house experience to work from, Ferreira will share her approach and tools for approaching the more complex, large-scale Phius projects.

She has outlined the following learning objectives for the workshop:

  1. Define Phius critical path items and process
  2. Explore strategies and tools for managing complexity
  3. Examine energy modeling approaches for large-scale projects
  4. Analyze Phius protocols unique to large-scale projects
John Loercher

John Loercher

Running concurrently is “WUFI Passive for Beginners” featuring Rensselaer Polytechnic Institute Building Science Program Director and Phius Certification Staff Member John Loercher. This session is meant both for those learning the WUFI Passive modeling tool for the first time as well as those who were exposed to it during CPHC® training, but have yet to use it on a project.

Katrin Klingenberg

Katrin Klingenberg

For those looking for a broader, more introductory workshop, there is “Passive Building 101” presented by Phius Co-Founder and Executive Director Katrin Klingenberg. This session offers a high-level overview of passive building, covering topics such as: passive house history, rationale for passive building standards, five core principles of passive building, certification processes, benefits of certification, and more!

Things won’t slow down on Oct. 13, as the sessions listed below make for a full day of passive building education and discussion.

  • Prescription for Better Buildings: Phius 2021 Prescriptive
  • Climate and Social Equity Workshop
  • Developer’s Multifamily Buildings of Excellence Case Studies
  • What’s My Size: Using the Newly Revised Manuals for VCHP Sizing

The “Climate and Social Equity Workshop” is free to attend, but registration is requested. It will be hosted by Clean Energy Works Managing Director Tamara Jones, HLW International Designer Satpal Kaur and Topsight Advisors LLC Principal Bomee Jung. The workshop will ask attendees to think critically about the topic of climate justice, which is the principle that actions to mitigate or adapt to climate change should equitably distribute their benefits, redress existing inequities, and dismantle institutional racism.

Mitsubishi Electric Trane US Sr. Product Manager Kimberly Llewellyn’s “What’s My Size: Using the Newly Revised Manuals for VCHP Sizing” workshop promises to be another highlight of the second day of Pre-Conference. She is one of the top mechanical systems experts in the country, and her presentation will focus on the management of humidity loads in high-performance buildings. Questions answered during the session are to include: When is an ERV enough to maintain acceptable interior conditions? What is the interplay of efficiency metrics for dehumidifiers vs heat pumps and where do rating metrics need to go in order to support development of HVAC equipment that can operate optimally in low SHF conditions?

We also don’t want you to forget about the New York City Passive Projects Tour, which is slated for Oct. 12 as well. Attendees will explore some of the largest, most innovative projects in the country. 

If you can’t get enough of Phius and passive house, you belong at PhiusCon 2021 Pre-Conference. Pre-Conference and Tour tickets are sold separately, so be sure to buy yours today!

 

Chicago Regulation Change Provides Opportunity for Phius Professionals

Al Mitchell

Al Mitchell

Phius Technical Staff Member Al Mitchell wrote this week’s blog post, which discusses the recent change in regulations related to coach houses in Chicago, and how designing these new buildings to Phius standards is a win-win for all parties.

The City of Chicago has lifted a nearly half-century ban on accessory dwelling units (ADUs), opening up a door for some people to build additional units on their property. The pilot program for ADU construction pertains to rentable units, occupiable by relatives, tenants, or even to be used as additional space from the primary home. There are two types of ADUs acknowledged by this regulation: a detached dwelling unit, such as a coach house or apartment on top of the garage, or a conversion unit, such as a built-out attic or basement.

However, there are a handful of caveats to consider. First, the allowances for ADUs, whether coach houses or conversion units, are limited to select pilot zones. There are five pilot zones: North, Northwest, West, South, and Southeast. These zones cover portions of 25 of the 77 Chicago community areas. Each area has a few special requirements for different types of ADU. For example, the North and Northwest zones can have a coach house built on the property before a primary house is built, while the other three zones require a primary house to be built on the lot before a coach house can be built. In the West, South, and Southwest zones, buildings must be owner-occupied in order to add a conversion unit. All ADUs in Chicago are to be rented for a minimum period of 1 month, and there is a requirement for a certain number of affordable units on larger properties where more units can be added.

 

Blog Pic 1This offers a great opportunity for people to add value to their property, create flexible living spaces (especially to take advantage of the benefits of multi-generational housing) or build a unit that can provide additional income for the owner while providing right-sized, cost-effective housing for another person. Approximately 70% of the lots in Chicago are 25 feet wide and face broadside south, making the applicability of this format broad. The aim of this blog is to make the case for building these newly allowed accessory dwelling units following the Phius passive building standards to create comfortable spaces, save energy and operational costs, and provide spaces that can weather inclement weather conditions, especially during a failure of space conditioning.

Analysis

Conversion units like the ones proposed in Chicago, would likely require a complete building retrofit to achieve the maximum cost and energy saving potential. This study is going to focus on detached coach houses, of maximum permitted dimensions. This comes at an apt time for Phius, as 2021 has marked the release of a user-friendly and streamlined prescriptive compliance path, as well as the performance target curves have been reworked to include allowances for small living spaces (in response to the tiny home craze).

Looking at coach house potentials, four cases were selected for evaluation. Three of the cases represent a single-story unit, one in the place of the garage, one pushed forward with open parking on the alley, and one built on top of the garage. The fourth case is a two-story coach house with no garage. The smaller units are studios, with no bedroom considered, one occupant, and the two-story coach house has one bedroom and two occupants. The standard kit of appliances is a dishwasher, refrigerator, and an induction range. Electric resistance water heaters are used in the base cases and a split heat pump system provides space conditioning.

The base cases follow code minimum constructions and windows per IECC 2018.  An envelope airtightness of 0.31 CFM50/sqft was used to match typical construction. The Phius CORE Prescriptive Path follows the prescriptive requirements per Chicago – Midway airport, and uses the default airtightness of 0.04 CFM50/sqft. The prescriptive path windows are whole window U-Values, and are set based on the required prescriptive comfort standards. Per the water heater efficiency requirements, the water heater was upgraded to a small heat pump water heater. The performance path uses 0.06 CFM50/sqft as the required airtightness metric, and follows the same window set as the prescriptive path. A heat pump water heater was used.  The other opaque assemblies were backed off from the conservative prescriptive path to meet the required calculated targets. Please reference the table below for the envelope performance specs in the study.

 

Case Wall R Roof R Slab R Window-U Airtightness CFM50/sf
IECC 2018 18.4 44.0 10.6 0.3 0.31
Phius 2021 CORE Prescriptive 40.0 71.0 21.6 0.16 0.04
Phius 2021 CORE 26.8 52.0 17.2 0.16 0.06
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Conclusion

The cases designed to Phius standards prove to reduce the space conditioning loads significantly, as shown in the Space Conditioning Results Chart. These outputs are specific per area, making it easy to compare different building sizes. Per the Source Energy Chart, the Prescriptive and Performance averages save 35% and 30% respectively. These source energy savings directly reflect the anticipated savings on an electrical power bill for the tenant of these coach houses.

Coach houses built to these passive building guidelines project significant energy savings that will directly benefit the occupants of these buildings, on top of the other comfort and passive survivability (what happens during a power failure – stay tuned for a part two blog). The required upgrades to meet the performance path is principally based around better windows and airtightness, saving on other insulation requirements per the prescriptive path. 

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It’s Here! The Phius Certification Guidebook v3.0

SONY DSCIn this week’s blog, Phius Associate Director Lisa White introduces the Phius Certification Guidebook v3.0 and explains how to get the most out of the newest guidebook iteration.

The Phius Certification Guidebook is the one-stop-shop for all things related to the Phius project certification program.

The guidebook contains information ranging from Tips for Designing a Low Cost Passive Building to Energy Modeling Protocols and What to Avoid. It continues to evolve alongside Phius’ growing certification program and standard updates. 

Guidebook CoverOne great reason to certify a project is to share knowledge with the passive building community, which accelerates growth. This guidebook is the keeper of that knowledge as well as lessons learned from the expanding base of certified projects. The Phius Certification team receives a myriad of questions from project teams related to unique circumstances and first-time design decisions that often require developing new guidelines and protocols to be applied on future projects — and those end up in the Guidebook. On top of that, the detailed review of projects throughout design and construction illuminates opportunities for the certification team to improve the guidance we provide to our constituents.

Version 1.0, released five years ago to support PHIUS+ 2015, clocked in at 87 pages. Version 2 followed to support PHIUS+ 2018 at 157 pages, and the most recent update, Version 3, supports Phius 2021, with 190 pages. The guidebook is a key resource for Phius professionals — but we’re often told it’s too long! I’m certain it can feel much shorter, and be incredibly useful, if you know how to navigate it. Anyone can get around a big city with the right map!

View this Table of Contents: Updates Summary which outlines what is new and updated in v3.0.

The document is split into 8 main sections followed by appendices.

The Sections

  • Sections 1 & 2 contain high-level information that is invaluable to first-time project teams and building owners/clients.
  • Section 3 is arguably the most important section, outlining all the certification requirements. Under Phius 2021, there are substantial updates to this section, most notably outlining the requirements of the performance and prescriptive paths side by side, as well as comparing and contrasting how each path handles items such as passive and active conservation strategies.
  • Sections 4 & 5 are key for setting expectations and understanding the workflows and fees associated with the certification process. There is a great high-level graphic showing three phases of certification steps at the beginning of section 4.
  • Section 6 is chock full of detailed energy modeling protocol. This section is laid out in order of the WUFI® Passive tree structure, guiding modelers top down with information ranging from early design defaults to detailed inputs for unique situations.
  • Sections 7 & 8 outline monitoring building performance as well as additional certification badges available. 

The Appendices

    • Appendix A is a consolidated resource about renewable energy. It explains how it can be used in the calculation of source energy use, and guidelines for procuring off site renewable energy.
    • Appendix B is likely the most often overlooked section, while also the appendix most referenced in project certification reviews. This appendix outlines the prescriptive approach to achieving moisture control in opaque assemblies. This most recent update splits this appendix into four types of guidelines: general, for walls, for roofs, and for floors. Do yourself a favor and vet the assemblies used on your next project (certifying or not!) against the guidelines listed here.
    • Appendices C & D are carried over from the previous version, outlining how to assess when a cooling system is recommended (App C) and internal load equipment tables for non-residential buildings (App D).
    • Appendices E, F, & G are great resources for the Phius Certified Rater or Verifier.  Appendix E is the Phius Certified Rater/Verifier manual. It outlines detailed technical inspection and field requirements, post-construction requirements, as well as how to maintain or renew the professional credential. Appendix F describes the procedure to prepare the building for airtightness testing, while Appendix G provides the onsite testing requirements for multifamily buildings.
    • Appendix H describes the Phius 2021 target setting updates, similar to what was found in the previously released “Standard Setting Documentation”
    • Appendix I is new to this version, and holds important information — most notably tips for passive building design about keeping costs low, assembly & window selection, and ventilation systems.
    • Appendix J talks about Co-Generation on-site, and how it affects the source energy factor for natural gas or grid electricity used on-site (depending on how the co-gen is prioritized). This is carried over from a previous version.
    • Appendix K is brand new, outlining definitions and requirements for electric vehicle charging infrastructure to supplement the requirement outlined in Section 3. EV capability is required in some fashion for all residential Phius 2021 projects.
    • Appendix L is also brand new and only applies to Phius CORE projects, as it describes electrification readiness requirements for combustion equipment. As a reminder, fossil-fuel combustion on-site is only permitted for Phius CORE projects, and not allowed for projects pursuing Phius ZERO or Phius CORE Prescriptive.
    • Appendix N closes out the document with normative information. Most notably, N-7 describes many of the underlying formulae for the Phius CORE Prescriptive path which is brand new to Phius 2021. It also contains the formulas and calculation methods used for lighting and miscellaneous electric load calculations, for example.

General Tips

  1. Utilize the Table of Contents and click to the section you need.
  2. Use the ‘find’ function (Ctrl+F) when in doubt of where to look to search for keywords. If taking this route, take note of what section your results are in – for example, is it a requirement or just informative?
  3. Bookmark the Guidebook link! (And follow Phius’ newsletters to be sure you’re aware when new versions are released).
  4. If you are the…
    1. Building Owner/Client — read Sections 1.1-1.4 and Appendix I-1 and review the graphic on the first page of Section 4.
    2. Project Team Member — read through Section 3 one time in its entirety if Phius Certification is a goal of the project. It’s only 18 pages, there are tables and pictures, and you can make it an excuse to have a beer.
    3. Project Submitter — read through Section 4 one time to set expectations, you will be happy you did. Also note Section 2.2, “Yellow Flag” items.
    4. CPHC / Energy Modeler — bookmark Section 6 for reference as you work through the WUFI Passive model.
    5. Phius Certified Rater/Verifier — bookmark Appendix E & F.
    6. One who loves the nitty gritty of passive building — print it, read it cover to cover.

Each iteration of the Guidebook reflects the aggregate knowledge gained by your efforts. Thank you! Feel free to use the comments section below for suggestions and questions.

On International Climate-Specific Passive Projects

Andres-vert3Phius Certification Team Member Andres Pinzon, PhD, explores the process of passive projects being built outside of the United States.

“Qué es una casa pasiva?” reads the cover of the drawing set of the Merlot House, a project submitted by CPHC Ignacio López pursuing PHIUS+ 2018 certification in Baja California-Mexico. This project — the first in this country — adds to the growing interest of Phius certification across latitudes.

During a regular week at Phius, we move between reviews on different climate zones, building functions and building types, assessing data from residential and non-residential, new construction, or retrofit. 

At first sight, the path toward certification may look intimidating, and we at Phius know that. Our team offers guidance and support for project submitters, especially when working on their first projects (overseas or not). The reviewers go above and beyond in helping project teams meet the specific, wide-ranged, and performance-driven goals of their buildings. This process offers achievable steps for certification within the context of each project.

How does Phius do it? The process includes: rounds of review, real-time feedback, conference calls, online open resources, etc. Phius tailors this process by providing solutions in compliance with certification, looking for red flags, and pointing out paths to avoid. This allows us to work with clients, architects, engineers, building scientists, etc. on the critical aspects of certifying a project in a particular part of the world.

Here are some remarks from our experience working with projects submitted to Phius outside of the mainstream of US and Canada.

The first step is generally custom climate data, followed by calculating the project-specific performance targets. Using the appropriate climate data and performance targets are essential to accurately modeling and reducing energy loads. Phius generates custom climate datasets for project teams that accurately represent their current project’s location. For most locations, we have not had trouble finding a TMY3 station within a (80-km) 50-mile range.  

In addition to climate data, marginal costs of electricity ($/kWh) at the regional/national level are needed to calculate the custom space conditioning targets they will use for certification. With this, teams can begin to work on comprehensive design and energy modeling; aware of the demands and loads that are expected for their buildings. 

Phius has projects in places such as Japan, Colombia, Nigeria and Mexico, where Phius certification represents a third-party verification on a desired performance for energy use and high-quality housing (see post on Housing Equity). The accumulated experience of different situations helps Phius come up with new solutions for diverse challenges and pass that knowledge to teams in subsequent projects.  

For example, approaches on cooling and dehumidification seen in Phius projects in southern states can guide us on how to tackle larger demands and peak loads in projects in tropical areas of South America or Africa. We see this potential in aspects such as: the enclosure’s insulation and airtightness, shading dimensioning and optimization to avoid overheating, and the proper selection and sizing of mechanical devices.  

Energy and carbon saving targets in buildings and operational budgets are a global concern. However, some information might be lost in translation when moving between countries, languages, cultures, or systems of measurement. In this sense, Phius is working on expanding the limits on a technical language that might hinder the domain of Phius projects.

Phius’ CPHC training is also offered and taught in SI units. In this way, professionals abroad who are interested in earning this credential can have access to material on building science principles, design exercises, and software tutorials prepared in the metric system. Furthermore, WUFI® Passive, the energy modeling software used for Phius certification, allows users to easily toggle between SI and IP units any time during the process.

More actions are in development within the idea of expanding the Phius community abroad. It is exciting to see creative and innovative approaches, integrating different sorts of information to make a high-performance building, such as the “bilingual” drawing set from the Merlot house. I cannot wait to attend the breakout session on international climate-specific passive projects at PhiusCon 2021 to continue the conversation.

EPA Indoor airPLUS and Radon Resistant Construction

0Today’s guest blogger is Tony Lisanti, PHIUS+ QA/QC manager. 

One of the prerequisite programs required for PHIUS+ Certification is the EPA’s Indoor airPLUS Program.  Born out of a need to minimize indoor air pollutants, the EPA dove-tailed this program with the ENERGY STAR Labeled Homes Program, which is also a prerequisite for the home or dwelling unit to earn both Indoor airPLUS and PHIUS+.  This serves to ensure that the dwelling unit is relatively tight, insulation is properly installed, the HVAC systems are properly sized, and bulk moisture throughout the building assembly is properly controlled.

Indoor airPLUS then takes indoor air quality to the next level. Integrating the Construction Specifications and Checklist requirements into the design, homes/dwelling units can then be verified to ensure greater precautions are taken for moisture control and dehumidification, air intakes are protected from birds and rodents, HVAC systems are kept clean, better filter media is used, and potential sources of moisture and contaminants are vented to the outdoors. Additionally, HVAC systems and ducts are prohibited in garages, pollutants from combustion equipment are minimized, and low VOC products are used.

One of the unique and important aspects of Indoor airPLUS is the requirement for radon-resistant construction measures in EPA Radon Zone 1. If you are not familiar with the Radon Zone map, it can be found here:  https://www.epa.gov/radon/epa-map-radon-zones.

Radon is a naturally occurring radioactive gas that can cause lung cancer. In fact, the EPA estimates that 21,000 deaths each year in the U.S. are attributable to radon exposure. The EPA has very good resources to read up on the health risks of radon. Their site can be found here: https://www.epa.gov/radon/health-risk-radon#head.

So why should PHIUS stakeholders be concerned with this? As mentioned above, PHIUS relies heavily on prerequisite programs such as ENERGY STAR and Indoor airPLUS. Since the airtightness standards for PHIUS Certified projects are up to 10 times more stringent than a typical code-built home, dilution of the indoor air cannot occur as readily. PHIUS ventilation requirements go well beyond those of systems found in typical Code built or even Energy Star Labeled homes. Good ventilation design, whether for code or for PHIUS starts with source control, i.e. minimizing the source of contaminants along with proper ventilation.

An example of a passive radon system.

An example of a passive radon system.

In high risk areas such as Radon Zone 1, EPA Indoor airPLUS requires installation of a passive radon system, at minimum. EPA also recommends utilizing active radon systems to further reduce radon concentrations in the home, although this is not yet an Indoor airPLUS requirement. The most modern radon standards are developed through an ANSI-accredited consensus process by the AARST Consortium (American Association of Radon Scientists and Technologists). EPA recommends following the ANSI/AARST CCAH Standard for 1-2 family dwellings and townhouses (max. total foundation area of 2500 sq. ft.) or the ANSI/AARST CC-1000 Standard for larger foundations, which often apply in multifamily buildings. However, the key components of a passive radon system for the purposes of Indoor airPLUS verification are succinctly outlined in Item 2.1 of their Construction Specifications.

ANSI/AARST will soon publish updated standards to provide guidance for the design and installation of two radon system options in new low-rise residential buildings. These systems, passive and powered, are designed to reduce elevated indoor radon levels by inducing a negative pressure in the soil below the building. The practice provides design and installation methods through soil depressurization systems that can be installed in in any geographic area.

Each of the two options consists of soil gas collection and a pipe distribution system to exhaust these gases. The first standard is for the design of passive radon reduction systems, sometimes referred to as a “radon rough-in” (ANSI/AARST RRNC). The second newly updated standard (anticipated in early 2020) includes details for a fan-powered radon reduction system, as well as radon testing (ANSI/AARST CCAH). Passive systems can result in reduced radon levels of up to 50%. These standards suggest that when radon test results for a building with a passive system are not acceptable, the system be converted to fan-powered operation. Typically, the action level is 4 pCi/L (Picocuries per liter). If the tested radon level exceeds 4pCI/L, then a fan is added to further depressurize the soil and positively vent the gas to the outside.

Recently, the EPA Indoor airPLUS team sent out this Technical Bulletin. The Technical Bulletin provides simple guidance on the installation of passive and active radon systems. Please pay particular attention to the drawings in the Bulletin, and note that the active system depicted has the fan located in a vented attic. This is outside the pressure/thermal boundary of the home. This has special significance with homes/buildings constructed to PHIUS Standards, because often, the attic space is WITHIN the pressure/thermal boundary of the home. Therefore, the fan cannot be located in the attic and must be outside the pressure/thermal boundary. The reason for this is, should there be a failure on the discharge or pressurized side of the fan, the building can actually be filled with radon gas.

Some other precautions that include a tight seal at the slab and vapor barrier to the vertical riser. Additionally, ensuring the riser is clearly labeled as “RADON” to minimize the chance that a plumbing waste line will be accidentally connected to it in the future is also important.

Tony Lisanti CEM, CPHC
PHIUS+ QA/QC Manager

With thanks to Nicholas Hurst from the EPA Indoor airPLUS Team