Energy Efficiency and Building Science News

ICC Confirms Validity of 2021 IECC Online Voting

Wed, 2020-03-18 11:45
Energy EfficiencyBuilding Science

The 2021 International Codes are currently going through our established validation process, conducted in accordance with Council Policy 28.

Click to enlarge (PDF).

As reported last month, the Validation Committee reviewed the third-party independent audit of the Group B online governmental consensus vote and confirmed that:

  1. Only eligible voters were given voting privileges via the online system.
  2. The vote tallies were accurate.
  3. The electronic system was secure and experienced no breaches.
  4. The voting was confidential and properly administered.
  5. The ballot period was opened and closed on time and within established procedures.

Over the past few weeks, International Code Council staff have taken a close look at the governmental voters, the process for validating voters, and potential voting irregularities, as requested by the Validation Committee.

Later this week the Validation Committee is meeting to review the results of this audit. Once that committee makes a determination, their recommendations will go before the Code Council Board of Directors, who will issue a final ruling on the Group B code changes. The Code Council will then issue a public report on the proceedings.

The Code Council remains committed to an open, transparent and balanced code development process, and we thank all our members and partners for their participation in this essential function. Please stay tuned for updates and visit our website to learn more.


'If Walls Could Talk' Explores Energy Code Trade-offs

Tue, 2020-03-17 17:36
Energy EfficiencyBuilding Science

At the recent 2020 RESNET Building Performance Conference, Jay Crandell (ARES Consulting) and Amy Schmidt (DuPont) gave a presentation titled “If Walls Could Talk…” The well-attended presentation explored why walls should be a priority and the impact of ignoring energy efficiency, durability, comfort, and serviceability.

In addition, this presentation explored various unintended consequences of energy code trade-offs allowed in the IECC and lack of coordination with water and vapor control provisions of the building code (IBC and IRC).  It also featured solutions based on newer energy code provisions forthcoming (2021 IECC) and updated water vapor control provisions coming in the 2021 IRC and IBC.

The audience was highly engaged with many insightful questions and observations. The overall response to the presentation was very positive, with one participant indicating “this was the best session at the conference.”

To view or download the slides from the presentation, please visit


Common Multifamily Building Envelope Design Mistakes

Tue, 2020-03-17 13:44
Housing & Construction

Although I'm an architect by training, I've worked for nine years as a sustainability consultant on low-rise multifamily projects. My designers and builders usually seek green building certification for their projects, whether ENERGY STAR or LEED for Homes. They want to be known for delivering high quality, high performance buildings.

Good intentions notwithstanding, I see the same mistakes again and again. This article covers the top four, all of which concern envelope detailing. Few projects have all these errors, but every project I see suffers from at least one of them.

These mistakes begin during design, which is why most of the live trainings I give on this topic are geared to architects. However, I also know that the most effective preventative measure is for educated architects and builders to help each other do good work. That benefits everyone.

The four top design mistakes are as follows:

1. Overcomplicated Geometry

Architects love to draw buildings with complex shapes. Maybe it's their training, or maybe it's because design competitions reward people who do something unique.

Either way, the belief that jogs, bump-outs, and cantilevers make a building more attractive is subjective, and tastes could change by this time next year. What's not subjective or temporary is nature: rain, wind, heat, sun, and gravity. These factors have way more impact on a building's durability and profitability than aesthetics, but people don't seem to spend enough time thinking about them.

A complex shape has more surface area than a simple cube. To build it you will need more materials and labor, and a longer construction schedule. Those jogs and bump-outs make it difficult to correctly install air and water barriers, which makes drafts and leaks more likely. They also complicate the insulation details needed to prevent thermal bridging. And with all that extra surface area, the mechanical system has to work harder to keep the building comfortable.

My point is not that you shouldn't incorporate interesting shapes into your design. However, you really need to be realistic about the costs of doing them right and the long-term risks to the building.

Figure 1

Figure 2

Although some architects love complexity, simple buildings have fewer problems and, as seen in the photo of these Brooklyn townhomes, can be quite attractive.

With that in mind, I want to make the case that simple buildings can be quite attractive if they're intelligently detailed. Just compare Figures 1 and 2, which show a complex apartment project and a row of condos in the Brooklyn's Park Slope neighborhood. The latter are simple, rectangular boxes but there's something very pleasant about the trim proportions and the regular window spacing.

2. Design Irregularities

This category includes a wide range of different errors. The big one is designing units in a wide variety of sizes and shapes, which unnecessarily makes life difficult for the rest of the project team, from the engineers and energy raters to the builders and their subs. All of this extra effort doesn’t come cheap, and it increases the chances for failure. Instead, consider offering a couple of floor plans and replicating them in a consistent fashion. Construction will be more predictable and it will be easier to correctly detail individual units.

Other problems include offering too many options in everything from light fixtures to mechanical systems. Keep it simple. Instead of spending time designing a good water barrier connection between three different types of cladding, just stick with one. Pick plumbing fixtures that are efficient, accessible, affordable and attractive, and use them as often as possible.

Of course, some architects can't help themselves and feel like they want to try a different design approach on every project. But the fact is that consistency is efficient and effective, and it can also make your designs more recognizable (and marketable).

To avoid unnecessary problems, costs and energy penalties, limit your offerings to a toolbox of proven design and construction details. If you want to show off your creativity, you can explore different ways of combining those details­—as long as you don't overcomplicate the building in the process.

3. Inadequate Air Barriers

This is more likely in complex buildings, but I also see it in the most simple of projects. Air barrier detailing is often left to the builder, but builders generally build the plan, so if the air barrier is not clearly defined there's a good chance it won't be done correctly.

You have to draw and detail the air barrier on the plans, and also include a performance requirement in the specs.

Figure 3

Click to enlarge.

Plans for a multifamily building should show the air barrier surrounding the individual apartments as well as the building as a whole. This is a classic belt-and-suspenders approach.

Some people ask whether the air barrier should enclose the building perimeter or individual units. My answer is that you need to do both. That means the plans will show a bunch of little bubbles surrounded by a big bubble, as in Figure 3.

Why seal each unit individually? For one thing, it's required by most green building programs. For another, airborne annoyances like sound and cooking smells travel more readily through leaks than through solid assemblies. Finally, compartmentalizing the building like this supplements the structural firestopping.

It's a classic "belt and suspenders" approach. The individually sealed apartments reduce air pressures on the building air barrier, which in turn reduces air leakage to the outside. The tighter the little bubbles, the less hard the big bubble has to work.

My company has written an air sealing guide that you can insert into your drawings or specs, but the best approach is to incorporate our details into your details. First, identify the location of the air barrier (for example, is it at the ceiling drywall or at the subfloor of the unit above?). Then zoom in on every connection, transition and penetration to anticipate how to stop air movement.

To ensure good results, some builders complete a few units ahead of time and have a consultant like myself run a blower door test on them. What if the don't meet the air leakage goal? "Oops," I tell them, "Remember all that stuff I told you do to? You're obviously not doing it." That can lead to some interesting conversations between the building owner or contractor and subs, but the problems usually end up getting fixed.

4. Thermal Bridging

Figure 4

This common slab-on-grade detail is a major thermal bridge. A better approach would be to put the insulation on the outside. Click to enlarge.

In case you haven’t heard it before, thermal bridging is where energy moves more quickly through the solid parts of an assembly. Basically it’s the path of least resistance between where energy is to where energy isn’t (inside to outside, or vice versa).

Preventing this means eliminating those paths, and the best approach is installing rigid foam on the outside of a roof, wall, floor or foundation. While this is simple in theory, not all thermal bridges are obvious, so in practice a lot of architects and builders miss them. These hidden bridges are more numerous on buildings with complex geometry, which is another reason to keep things simple wherever possible. (If you detect a theme here, you're right.)

However I also see a lot of thermal bridging on simple assemblies like slabs on grade, as you can see in Figure 4. The part of the assembly with the most heat transfer has the least insulation!

There are way too many potential thermal bridges to point out in a short article. The point is that you have to think through the insulation details on the plans and predict how heat might move through or around them. If you see any short circuits, then you need to add details to eliminate them.

The above errors aren't the only ones I see in multifamily projects. Other common ones include a lack of lighting controls, improperly sized HVAC, antiquated ventilation and oversized domestic hot water distribution. I cover these in my live trainings (including one at the 2019 EEBA Summit), but you can also find more information here.

One last point: Preventing these issues doesn’t just happen on paper; it requires collaboration and communication. In fact, I find that good communication—between the architect, consultants, builder, subs and the building owner—to be the major difference between a successful project and a failure. If everybody is on the same page and willing to learn from each other, your chance of creating a high quality and cost effective building increases exponentially. Who wouldn’t want that?


Could Bipartisan Energy Efficiency Bill Save Consumers $51B?

Tue, 2020-03-10 16:14
Energy EfficiencyBuilding Science

Credit: Creative Commons

  • Bipartisan, bicameral legislation to boost the energy efficiency of homes and commercial, industrial and federal buildings, could save $51 billion on energy bills through 2050 according to new analysis from the American Council for an Energy-Efficient Economy (ACEEE). 
  • Critics of the bill, however, told a U.S. House subcommittee on Wednesday that more aggressive building codes for energy efficiency could harm housing affordability through "costly and aggressive" requirements on homebuilders. The committee chair also pressed a Department of Energy official on appliance standards that have yet to be updated.
  • The most significant portions of the Energy Savings and Industrial Competitiveness Act would modify national building codes to make new homes and commercial buildings more energy efficient, provide retrofitting assistance for schools, and create a program to account for efficiency in the mortgage appraisal and underwriting process for federally-backed mortgages.

The energy subcommittee of the House Committee on Energy and Commerce heard discussion on six bipartisan efficiency and energy storage bills, but the most contentious moment focused on appliance standards.

Rep. Frank Pallone, D-N.J., chairman of the full committee, repeatedly pressed Under Secretary of Energy Mark Menezes on what the U.S. Department of Energy is doing to update energy standards for appliances — and never appeared satisfied by the responses.

"The question is, are you actually doing anything to promote energy efficiency? You're just talking to me about process," Pallone charged.

Energy efficiency advocates say DOE under President Donald Trump has missed 18 deadlines to review standards. Menezes assured lawmakers "we have full intention of following all of our legal obligations," and said seven standards have been finalized under Trump. But he also said the problem had been "inherited." 

By statute, DOE must review each appliance standards once every six years to determine if an update is warranted. If it finds that an update is warranted, it must publish that update within an additional two years, according to Andrew deLaski, executive director at the Appliance Standards Awareness Project.

"When this administration took office, DOE had missed 3 deadlines. That number has now grown to 21," deLaski told Utility Dive in an email.

"It's not a simple thing," Menezes said, defending the administration's work. "There's testing and evaluation and quite a stakeholder process involved. ... You can compare our record to any prior administration in getting these out."

The rest of the hearing was less charged, though Menezes did hint at potential disagreement with some of the legislation being proposed. In particular, discussion focused on the bill to change the national building code.

"This is a very comprehensive bill and quite creative," Menezes said. "The art will be in the drafting."

In the Senate, the bill was sponsored by Sens. Jeanne Shaheen, D-N.H., and Rob Portman, R-Ohio. The House companion was sponsored by Reps. Peter Welch, D-Vt., and David McKinley, R-W.Va.

Along with building codes, the legislation would encourage efficiency technology and processes for industrial applications, expand DOE's Industrial Assessment Centers, and incentivize the use of more energy-efficient electric motors and transformers. 

"We don't do everything that is in the bill," Menezes said. "The rebates would be new. It is significantly broad, that we are continuing to look at the bill ... From personal experience, it is the kind of bill that would fit in well with a comprehensive view."

Menezes, earlier in the hearing, told lawmakers that Sens. Lisa Murkowski, R-Alaska and Joe Manchin, D-W.Va., have indicated to him they may be introducing a comprehensive energy bill later this month in the U.S. Senate Energy and Natural Resources (ENR) Committee. He also said the Trump administration has not taken a formal position on the any of the bills, though it has provided some technical assistance in drafting.

A spokesperson for the ENR committee Grace Jang confirmed that comprehensive energy legislation could be coming later this month.


2021 I-Codes: Stucco WRB Enhancements Mitigate Inward Vapor Drives

Fri, 2020-03-06 16:58
Energy EfficiencyBuilding Science

As mentioned in a prior January 2020 EEBS article (2021 I-Codes Adopt Major Energy Efficiency & Building Science Advancements), many advancements forthcoming in the 2021 ICC family of codes (energy and building codes) were overviewed with the intent to address these advancements individually in future articles.  Well, here’s the first installment and it addresses some very useful improvements and clarifications made to the Portland Cement stucco water-resistive barrier (WRB) provisions.

Reservoir claddings, like Portland cement (conventional) stucco, adhered masonry veneers, and anchored brick masonry veneers to name a few, can absorb and store significant amounts of rainwater. When solar-driven drying occurs after a rain event, the inward vapor drives can readily exceed the magnitude of outward vapor drives experienced during the winter (see Figure 1). This can result in elevated exterior sheathing moisture contents, and for buildings that are air-conditioned in the summer, condensation on the interior vapor retarder or high moisture contents in interior finishes.  Consequently, some enhanced practices are necessary to protect the moisture-sensitive portions of the wall assembly from wetting due to inward vapor drives.

The 2021 editions of International Building Code (IBC) and International Residential Code (IRC) have effectively responded. 

Figure 1. Inward Moisture Movement Due to Reservoir Cladding and Solar Radiation. Click to enlarge. For additional information, visit Continuous Insulation's Water Vapor Control web page.

In a traditional successful approach, the reservoir cladding is back-ventilated to help remove the water vapor being driven inward as the cladding attempts to dry both inward and outward (see Figure 1).  This is the long-standing practice employed with anchored brick masonry veneer by use of a 1-inch air gap and vent or weep holes in the veneer.  In another successful approach commonly used with stucco, inwardly-driven water vapor can be blocked by placing an “intervening layer” of low vapor permeance “non-water absorbing” material between the reservoir cladding and the remainder of the wall assembly. 

Foam sheathing continuous insulation is commonly used for this purpose and, in colder climates, it must be used in the appropriate amount together with an interior vapor retarder to effectively control wintertime outward vapor drives (more on this to come in a future article which will discuss coordinated advancements in the 2021 IBC and IRC water vapor retarder provisions; in the interim please refer to the wall calculatorsResearch Report 1410-03 Assessment of Water Vapor Control Methods for Modern Insulated Light-Frame Wall Assemblies and Research Report 1701-01 Model Moisture Control Guidelines for Light-Frame Walls: A Building Code Supplement for Builders, Designers, and Building Officials).

Finally, in rainy climates, it is important to provide at least a small drainage gap and pathway to efficiently remove bulk water from rain intrusion through the reservoir cladding which would otherwise add to the inwardly-driven water vapor load. This gap also allows for what is known as “hygric re-distribution” (for more information please refer to see BSC article: “Drain the Rain, On the Plane. The Drainage Plane.”

The 2021 IBC and IRC code improvements to address the above principles are shown in Figure 2 below (only the IBC text is shown; the IRC text is identical).  The requirements also vary according to “dry” or “moist” and “marine” climate zones shown in Figure 3.

2510.6 Water-resistive barriers. Water-resistive barriers shall be installed as required in Section 1403.2 and, where applied over wood-based sheathing, shall comply with Section 2510.6.1 or Section 2510.6.2.

2510.6.1 Dry climates. One of the following shall apply for dry (B) climate zones:

  1. The water-resistive barrier shall be two layers of 10-minute Grade D paper or have a water resistance equal to or greater than two layers of water-resistive barrier complying with ASTM E2556, Type I. The individual layers shall be installed independently such that each layer provides a separate continuous plane and any flashing, installed in accordance with Section 1404.4 and intended to drain to the water-resistive barrier, is directed between the layers.
  2. The water-resistive barrier shall be 60-minute Grade D paper or have a water resistance equal to or greater than one layer of water-resistive barrier complying with ASTM E2556, Type II. The water-resistive barrier shall be separated from the stucco by a layer of foam plastic insulating sheathing or other non-water absorbing layer.

2510.6.2 Moist or marine climates. In moist (A) or marine (C) climate zones, water-resistive barrier shall comply with of one of the following:

  1. In addition to complying with Item 1 or 2 of Section 2510.6.1, a minimum 3/16 inch (4.8 mm) space shall be added to the exterior side of the water-resistive barrier.
  2. In addition to complying with Item 2 of Section 2510.6.1, a space with a minimum drainage efficiency of 90% as measured in accordance with ASTM E2273 or Annex A2 of ASTM E2925 is added to the exterior side of the water-resistive barrier.

Figure 2. 2021 IBC Stucco WRB Provisions

Figure 3. U.S. Climate Zone Map (also to be updated for the 2021 I-Codes) Click to enlarge. For additional information, visit Continuous Insulation's Water Vapor Control web page.

These improved provisions do two very important things consistent with the above-described principles.  First, they allow traditional practices to be continued where they have been successful in the “dry” climate zones (see Section 2510.6.1 in Figure 2 and Figure 3 for the “dry” climate region). It also clarifies that the nebulous intervening “non-water absorbing layer” placed between the stucco and the WRB layer has always been intended to apply to materials like foam plastic insulating sheathing (see Section 2510.6.1 option #2 in Figure 2).  In addition, the traditional WRB requirement in option #2 (i.e., 60-min Grade D paper) is clarified to allow alternative WRB materials with at least equivalent water resistance of ASTM E2556 Type II, such as various building wrap materials. But, this also provides flexibility to use other materials like some foam sheathing products to serve as the WRB layer where approved for that purpose and also having a water-resistance equivalent to ASTM E2556 Type II.  However, in this latter case, a separate bond-break or non-water absorbing layer must be applied over the foam sheathing WRB as shown in Figure 4 (i.e., the foam sheathing is used as the WRB, not as the intervening non-water absorbing layer). In both cases, as a WRB layer or as an intervening “non-water absorbing” layer, the foam sheathing also serves as a “block” or retarder to inward water vapor movement from the stucco.

Figure 4. Example of a stucco application variation with foam sheathing WRB layer and a separate non-water absorbing (bond break) layer over the foam sheathing (NOTE:  In “moist” and “marine” climates, a means of positive drainage is additionally required for all stucco applications per Section 2510.6.2 of Figure 3).

Second, the new code language provides additional enhancements that are required for use of stucco in the “moist” and “marine” climate zones (see Section 2510.6.2 in Figure 2 and Figure 3).  There are two options for compliance: (1) use of a prescribed minimum 3/16-inch-thick drainage space to the exterior side of the water resistive barrier (behind the stucco) or (2) a space with a minimum drainage efficiency of 90% as measured in accordance with two commonly used ASTM standards. 

This provides a simple prescriptive solution and also performance-based solutions allowing use of proprietary drainage materials and methods such as grooved foam sheathing, drainage mats, or building wraps that provide adequate drainage space or drainage performance.  This practice will help to mitigate moisture issues that have occurred behind stucco and adhered veneers (e.g., reservoir claddings) in moist regions of the U.S.

It should be noted, however, that the above provisions only apply where wood-based sheathing is used on the exterior side of a wall supporting the stucco (consistent with prior editions of the IBC and IRC).  Thus, for all other sheathing materials (regardless of their moisture sensitivity) the only thing the code continues to require is a WRB behind the stucco (without a drainage space) in any climate and irrespective of the amount rain or moisture hazard.  For other types of sheathing that are sensitive to moisture, it is recommended that the provisions aimed at wood-based sheathing be used, even though not required by the code.


Why Cavity & Continuous Insulation Definitions Matter!

Fri, 2020-03-06 16:32
Energy EfficiencyBuilding Science

Language can be a tricky thing. Some words mean one thing to one person and something very different to another. In the realm of code-compliance and enforcement, this can result in confusion or even misapplication of the building code or energy code. Without clear definitions the code may be subject to varying interpretations that may depart from the intent. Definitions are important and they have significant technical implications. This even applies to the basic application of insulation components on a building envelope, such as continuous insulation and cavity insulation.

Continuous insulation has been defined in the International Energy Conservation Code (IECC), International Building Code (IBC), and International Residential code (IRC) for several editions. A cavity insulation definition also has been added to the 2021 edition of the IECC, having previously been introduced only in the 2018 IECC commercial provisions. 

Cavity Insulation. Insulating material located between framing members.

Continuous Insulation (ci). Insulating material that is continuous across all structural members without thermal bridges other than fasteners and service openings. It is installed on the interior or exterior or is integral to any opaque surface of the building envelope. 

Why are these definitions important? The application and location of insulation materials (regardless of material type) matters. There are many types of cavity insulation and also continuous insulation. But, the effectiveness of those materials depends heavily on their location in the envelope assembly. Cavity insulation materials are located between framing members and, consequently, are thermally bridged by framing members like wood or steel framing (see Figures below). Continuous insulation materials are, as the definition indicates, continuous. They are not to be bridged by major structural elements like framing or floor edges (see Figures below). 

All of this seems obvious, but the significance of these definitions are often over-looked in complying with the energy code’s thermal insulation requirements and this can have a significant effect on the thermal and moisture performance and code-compliance of the building envelope. In some cases, the rated R-values of these two insulation components are wrongly added together as a means of energy code R-value compliance which disregards the difference in their effectiveness based on location on or in the envelope assembly (See prior article Energy Code Math Lesson: Why an R-25 Wall is Not Equal to a R-20+5ci). Similarly, the distinction is important for proper use of the vapor retarder provisions in the building code where the amount of continuous insulation relative to cavity insulation (e.g., insulation ratio) is used together with water vapor retarder specification to control water vapor and keep walls dry and warm in the winter (refer to wall calculators, Research Report 1410-03 Assessment of Water Vapor Control Methods for Modern Insulated Light-Frame Wall Assemblies and Research Report 1701-01 Model Moisture Control Guidelines for Light-Frame Walls: A Building Code Supplement for Builders, Designers, and Building Officials for more information).

We will be building on these definitions and applying them with a focus on the continuity of building envelope “control layers” (e.g., thermal, water, vapor, air) in a series of future articles. Stay tuned.


Video: Builder Uses Latest Building Science for Foundation

Fri, 2020-03-06 15:33
Energy EfficiencyBuilding Science

The 2016 Fine Homebuilding (FHB) House is energy-smart, connected, healthy, and durable. It’s small and sensible. Most of all, it’s a valuable model home, meant to educate designers and builders who aspire to create high-performance houses that are exceptional in their quality, comfort, and style.

FHB House builder Mike Guertin and designer Michael Maines conceived of the project’s foundation with buildability, water management, and thermal performance in mind. In this video, Guertin explains his approach to the construction of the foundation from forming the footings to installing the final drainage membrane. Using a combination of insulated concrete forms, rigid foam, and a host of waterproofing products, the team was able to construct a foundation with above-average performance attributes that can be replicated easily by any builder.

Find more details about the construction of the FHB House foundation:


How the 2021 IECC Will Impact HERS Raters and Builders

Fri, 2020-03-06 15:29
Energy Efficiency

The 2021 International Energy Conservation Code (IECC) was finalized at the end of 2019 through an online vote of the governmental members of the International Code Council (ICC). RESNET participated in the process in support of RESNET standards and the Energy Rating Index (ERI) compliance path. This post will outline the key results that will impact HERS Raters and the builders they work with.

Click to enlarge.

Standards 301 and 380 Updated.

The committee decision to approve Standards 301 and 380 in Albuquerque was upheld through the public comment hearing process and both standard references will be updated to their current 2019 versions.   The updated version of Standard 301 includes the house size adjustment factor, improved calculations for domestic hot water, recognizes advances in solid state lighting and improved and expanded consideration of multifamily dwelling units. The most significant change in the updated version of Standard 380 is the inclusion of criteria for testing of attached dwelling and sleeping units in buildings of all heights.

Another committee decision that was upheld through the public comment hearings was to approve the reference to Standard 380 for conducting duct leakage testing. Although this standard was referenced for envelope leakage testing in the 2018 IECC, it was not referenced for duct leakage testing in that code. Another duct testing proposal, that was adopted in the 2021 IECC eliminates the exception that allows HVAC equipment located entirely in conditioned space to not be tested. Under the 2021 IECC all ducts will be required to be tested, regardless of location.

What happened to the ERI?

A number of changes to the ERI, Section R406 are detrimental to the viability of this compliance path. In the 2018 IECC, the ERI is considered the most stringent compliance path, and in the 2021 code the lopsided compliance paths get even worse. First, proposal RE192 makes the ERI target scores more stringent in each climate zone. This proposal was disapproved by the committee by a 10-1 vote, but later approved in online voting and revises ERI target scores from a 51 to 55 depending on climate zones.

The approval of proposal RE184 further hamstrings the ERI by limiting renewable energy production to reduce no more than 5% of total energy use. Proposal RE209, which applies additional efficiency improvements to all compliance paths, will require anyone using the ERI to further reduce their target score by 5%. This means actual mandatory ERI target scores will range from 48 to 52, depending on climate zone.

However, the changes to the ERI path don’t stop there! 

You may recall that the 2018 IECC revised the ventilation requirements for the reference home, which led to an increase of 2 to 8 points in ERI scores. A proposal submitted by Joe Lstiburek that would have fixed this issue (RE186) was approved by the assembly during the Las Vegas Public Comment Hearings with no testimony in opposition but was subsequently overturned during online voting.

All these changes mean a builder would need to achieve a HERS Index score of between 40 and 50 to hit the revised ERI targets and can only claim a 5% reduction in energy use for renewable energy.

If you’re curious about the differences between an ERI score and a HERS Index score, click here.

What does this mean for ERI?

Unfortunately, the changes made to the ERI for the 2021 IECC mean this path, that saw little use in the 2018 code, will no longer be a viable compliance option. As HERS Raters increasingly become the go-to resource for energy code compliance, they will choose the best compliance option for their builder clients. If recent trends continue, the energy code compliance path of choice for HERS Raters will be the Performance Path. Since compliance with both the ERI and Performance paths is demonstrated using RESNET-accredited software it is easy for HERS Raters to use the path that is most cost effective for their builder clients.

Other notable changes.

In the commercial section of the IECC, there was an important proposal, CE96, that will allow the testing of dwelling and sleeping unit enclosures to be done in accordance with Standard 380 and tested to a metric of cfm/ft2 instead of ACH50. The proposal allows for an air leakage limit not to exceed 0.30 cfm/ft2 of enclosure area.

Finally, proposal RE223 approved a new appendix for achieving net-zero energy homes. As an appendix, it means it is optional and a jurisdiction would need to adopt it before it can be used. Since the proposal directly references ANSI/RESNET/ICC 301, it bypasses the ventilation issue in the R406, ERI path. The appendix would require a target score between 43 and 47 without accounting for renewable energy and a score of zero when renewable energy is included. RESNET supports the push toward net-zero energy and believes this type of appendix is a great option for jurisdictions ready to make the move.

What’s next?

With multiple compliance paths in the IECC, it is important to provide balance in stringency among them. Unfortunately, the ERI path in the 2021 IECC has target scores that effectively hit the same level of stringency as the net-zero appendix, without renewable energy. This is a stringency level far beyond the prescriptive and performance paths which means HERS Raters are likely to choose the easier compliance paths for most of their builder clients. The 2021 codes should be published later this year, but most likely will not see any widespread adoption for several years to come.


NAHB Testifies Against Energy Efficiency Measure in House Bill

Mon, 2020-02-17 16:12
Press ReleasesEnergy Efficiency

The National Association of Home Builders (NAHB) on Feb. 12 urged the House to oppose to H.R. 3962, the Energy Savings and Industrial Competitiveness Act of 2019, warning that the legislation would exacerbate the nation’s housing affordability woes.

Testifying on behalf of NAHB before the House Energy and Commerce Subcommittee on Energy, Arn McIntyre, a green builder from Grand Rapids, Mich., said that several provisions in H.R. 3962 would needlessly raise home construction costs while doing little to boost energy efficiency in the housing sector.

“This legislation would harm housing affordability as a result of its mandates for overly costly and aggressive energy efficiency requirements to be included in model building energy codes,” said McIntyre. “NAHB is also concerned that the bill will expand the federal government’s authority over state and local governments’ prerogatives to adopt cost-effective and location-appropriate building codes.”

With the nation in the midst of a housing affordability crisis, McIntyre added that H.R. 3962 would worsen the problem by:

  • Focusing on initiatives that will increase costs for new housing and buildings while ignoring the existing older structures, which constitute more than 80 percent of the U.S. building stock and are responsible for an even greater portion of greenhouse gas emissions and energy consumption;
  • Failing to establish reasonable criteria for technology readiness or meet the economic payback period expected by the consumer (less than 10 years) for any minimum code requirement or proposal supported or initiated by the Department of Energy (DOE);
  • Empowering the DOE to advocate for overly prescriptive, not fully vetted, and costly energy targets for new residential buildings; and
  • Authorizing the DOE to impinge on the states’ abilities to customize model codes to meet their specific jurisdictional goals to improve building performance.

“NAHB wants to work as a partner with all levels of government to encourage energy efficiency,” said McIntyre. “However, we must all work together to ensure housing affordability is not jeopardized in the process. Therefore, NAHB urges Congress to focus on solutions that are market driven, such as above code voluntary programs and other incentives, and to focus on increasing the energy efficiency of the existing housing stock.”


Homebuilders Cry Foul After 2021 IECC Online Voting

Mon, 2020-02-17 16:08
Energy EfficiencyBuilding Codes

For most of 2019, the International Code Council’s 2021 building codes cycle was moving along as expected. But a last-minute wave of newly-registered voters appears to have derailed the online vote in what appears to be a concerted effort to impact the code development process.

NAHB was heavily involved at all stages in the current code development cycle, which includes changes to the International Energy Conservation Code (IECC) and the all-important International Residential Code (IRC) for the 2021 edition of the I-Codes. NAHB members and staff had a significant presence at both the ICC Committee Action Hearings in Albuquerque last May and the Public Comment Hearings in Las Vegas in October.

Through the deliberative and transparent hearing process established by the ICC, NAHB — along with a host of other advocates and stakeholders along all ideological lines — publicly influenced many proposals with testimony backed by data and relevant research.

When the vote results came in from the ICC’s Online Governmental Consensus Vote, held Nov. 19 through Dec. 6, 2019, it was as expected, with a success rate of around 84% on non-energy code proposals that NAHB either supported or opposed, in line with results from previous years. But when the preliminary results on the IECC were reported, there were some surprising discrepancies.

Many aggressive energy efficiency proposals that had been defeated at both the committee hearings and the public comment hearings had been approved by the online vote (preliminary results). When proposals are defeated at hearings, they must get a two-thirds majority to overturn past results. It’s a bar so high, no previous proposal had ever met the threshold. But in this code cycle, 20 IECC “zombie” proposals cleared the hurdle and came back to life. And some will negatively impact housing affordability for home builders and buyers.

The more egregious changes include:

  • Gas water heaters, stoves and dryers need to be “electric ready,” with appropriate receptacles installed nearby if a home owner decides to switch to all-electric appliances
  • An electric vehicle charging receptacle (40A 220V) needs to be installed in all single-family homes with a parking space
  • Wall insulation was increased to R-20+5 in climate zones 4 and 5
  • Ceiling insulation was increased to R-60 in climate zones 4 through 8
  • Ceiling insulation was increased to R-49 in climate zones 2 and 3

A preliminary NAHB analysis of the changes pegs the cost impact to be a low-end estimate of $2,400-$7,200 in climate zone 1, to a high-end estimate of $5,000-$14,000 in climate zones 4 and 5, for each new single-family home of average size.

With such inconsistent results, NAHB suspected that something was amiss with the voting. After reviewing the approved governmental voters, it was discovered that hundreds of new government employees from towns all over the country were validated to vote — and they voted in droves.

There was a concerted effort on the part of efficiency and environmental groups to engage like-minded governmental members who work in environmental, sustainability and resilience departments. These new voters appear to have worked off the same voting guide and simply voted their party line.

NAHB will be very actively pushing back on these zombie proposals. First, staff is appealing at least two of the results that they believe are related to proposals that are out of scope for the energy code. Also, NAHB will be challenging the voting credentials of a number of new members.

NAHB also intends to work with ICC to tighten up voting eligibility and modify the process to limit or eliminate proposals from getting approved that lose the first two hearings.

For now, read the results and know that NAHB is doing all it can to stand up for reasonable building codes that help build safe housing that is affordable.

For more information on the vote or the codes development process, contact Craig Drumheller.


Leading Builders Ask ICC to Review Group B IECC Results

Mon, 2020-02-17 16:01
Energy EfficiencyBuilding Science

The code development process for the 2021 International Codes is in its final stages. The code hearings are complete, and last month the International Code Council released the preliminary results from the Group B Online Governmental Consensus Vote (OGCV).

Click to enlarge.

The Validation Committee is in the process of validating the results. This committee is appointed by the Code Council Board of Directors and is comprised of experienced participants in the code development process. They have already confirmed that the information technology infrastructure worked correctly and was secure and free from malicious errors.

Code Council staff are working with the Validation Committee to examine issues raised in two letters – one from Thomas Zaremba, Partner at Roetzel & Andress, and the other from Leading Builders of America. These letters ask for further clarification about the voting results with respect to energy efficiency code changes and the voter validation process.

We are conducting an audit and review as is a normal part of our code development process to assure accuracy. Our consensus-based process is designed to be transparent, open and balanced, and we are handling these requests quickly and thoroughly.

This cycle had more participants than any previous cycle. Our members considered 388 code changes at the Public Comment Hearings (PCH) and OGCV. Over 240,000 votes were cast at the combined PCH and OGCV.

We will continue to provide regular updates as these requests are resolved. 

Visit our website to learn more about the code development process. Council Policy 28 for more information about the process. Click here for information concerning the Validation Committee.


Today’s Webinar: Evaluating the Impact of the 2021 IECC

Mon, 2020-02-17 15:50
Energy EfficiencyBuilding Codes

Title: The 2021 IECC: How Local and State Officials Just Took a Giant Leap Toward Net Zero Buildings in America

When: Wednesday, February 19, 2020, 2:00 p.m. (Eastern)

Who: Bill Fay, Energy Efficient Codes Coalition (EECC)

Late last year, local and state officials voted in droves to boost building efficiency in the 2021 update to America’s Model Energy Code – the International Energy Conservation Code (IECC) – by 12-17%.  Their collective two-year get-out-the-vote campaign was dedicated to writing a new IECC that will help them meet their energy and climate policy goals. 

Among those leading the effort were governmental officials from the U.S. Conference of Mayors, National League of Cities, the National Association of State Energy Officials, and the Urban Sustainability Directors Network. This webinar is your chance to hear how the new 2021 IECC tackles the nation’s largest source of energy consumption and carbon – our buildings –slashing energy bills, stabilizing grids, and meeting Paris Accord targets!

EECC’s Bill Fay will lead a discussion with some of those Governmental Member Voting Representatives on the challenges ahead for the 2021 IECC:  defining, promoting, defending and, ultimately adopting it across the nation.

Fill out this form to register.


Insulation Industry National Policy Conference May 19-20

Fri, 2020-02-14 15:48
Press Releases

Registration is now open for the 2020 Insulation Industry National Policy Conference. This year’s event will take place May 19-20, 2020 at the Capital Hilton in Washington, DC.

The conference is an opportunity to network with members from the insulation industry, meet with legislators to discuss our industry’s policy priorities, and learn from experts on a variety of topics. More information on topics and speakers will be shared throughout the spring.

Click here to register for the conference.


State Building Code Updates for FL, MD, and WA

Fri, 2020-02-14 15:46
Energy EfficiencyBuilding Codes

Below are brief summaries of legislative actions being taken that would impact building codes:

Legislation has been introduced in the Florida House and Senate that would require manufacturers to provide code officials with product test reports upon request. HB 511 and SB 732 are intended to hold manufacturers accountable for testing residential insulation products in accordance with ASTM standards.

A Maryland bill (HB 153) introduced this week extends the time from 18 months to 36 months within which the Maryland Department of Labor is required to adopt each subsequent version of the Maryland Building Performance Standard, their statewide building code. This change may significantly alter the timeline for adoption of newer versions of the IECC and/or provisions therein favorable to the foam insulation industry.

HB 2667 would require the Washington State Building Code Council to delay implementation of the 2018 state residential energy code and would prohibit the Code Council from increasing energy efficiency requirements in the code.


Improving the Envelope with the New C3 Engineered Wall System

Fri, 2020-02-14 15:36
Energy EfficiencyBuilding Science

Insulating layers keep the rain out without compromising air circulation. Below is a new product on the market for residential construction.

C3 Engineered Wall System
MgO Systems

Combining fireboard with structurally insulated panels, this barrier solution provides thermal and acoustic insulation. In addition to being resilient to fires, the prefabricated system reduces installation time and construction waste.

Are Net-Zero Passive Houses the Industry’s End Game?

Fri, 2020-02-14 15:31
Energy EfficiencyBuilding Science

The energy savings from net zero passive houses can reduce heating costs by 75% to 90%, and these new dwellings have a much longer life span, writes Passive Design Solutions’ Natalie Leonard. She says ensuring that all new structures achieve significant and permanent energy reductions will require financial incentives to facilitate the replacement of existing homes.

The building sector accounts for 50% of all energy used in North America but has not achieved significant improvements in energy efficiency and carbon emissions like that of the transportation and durable goods sectors.

One part of the building sector deserving attention is detached single-family housing. In 2018 the U.S. had about 83 million detached houses and Canada had about 7.67 million. From January to September 2019 there were 653,300 single‐unit housing completions in the United States, and 45,086 single-family house completions in Canada.

Retrofitting existing houses is expensive and may, at best, only result in energy savings of 30% compared to other dwellings in the same location that have not been retrofitted. On the other hand, the energy savings of new construction can reduce heating costs by 75% to 90%. Moreover, new buildings have a much longer life span over which to amortize and enjoy the additional energy and cost savings.

Photographer: Daniel Acker/Bloomberg

Simply renovating existing houses to improve their energy efficiency, although important, does not give optimal results. Nor is it the most cost-effective approach in every instance. The gold standard for optimizing the energy efficiency of an existing house is its replacement. At first, this may seem excessive. However, there is a rationale for this approach, and it has to do with the rather slow rate at which older, less energy efficient housing is replaced with new, more energy efficient housing.

Given the large inventory of new and existing detached houses, it is clear that any public policy intending to make meaningful reductions to national building energy use must address this housing sector. A net zero passive house replacement can provide significant energy savings, with a design that is durable and low maintenance.

Net Zero Passive Houses

Net zero is defined in a number of ways. A useful definition says that a net zero building is one with zero net energy consumption, meaning the total amount of energy used by the building on an annual basis is equal to the amount of renewable energy created on the site.

Passive house is a voluntary standard for energy efficiency in a building, which reduces the building’s ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling.

Net zero houses are not necessarily passive designs, and passive houses are not necessarily net zero. But augmenting passive house design with modest on-site, grid-tied electrical power generation provides a simple path to net zero that can be implemented for a modest premium: 5% to 15% over code-built alternatives. And they achieve a 75%-90% reduction in heating costs, with annual heating bills as low as $150.00.

Canada’s National Energy Code for Buildings (NECB) 2017 says the “most cost-effective time to incorporate energy efficiency measures into a building is during the initial design and construction phase. It is much more expensive to retrofit later. This is particularly true for the building envelope”, which is the single most important element of an energy efficient dwelling.

The Environmental Change Institute at Oxford University has argued that between 2005 and 2050, 3.2 million dwellings must be demolished and replaced for the U.K. to reach its national energy reduction targets for housing.

The Oxford research recognizes that some dwellings require prohibitively expensive repairs before energy reduction measures can be implemented, and even then, the results are unimpressive.

In the same vein, Low-Income Energy Efficiency Program (LIEEP) contractors in Maryland found significant pre-existing health and safety deficiencies in houses identified for efficiency improvements. The improvements could not proceed until repairs were completed.

Many Attractive Benefits

A net zero passive house is not a “new-age” compromise. Instead, it is a versatile housing solution that provides a number of attractive benefits:

  • Significant reduction in heating costs over code-built houses;
  • Reduced carbon footprint;
  • Superior indoor comfort—the bright, draft-free and consistently warm spaces are what owners most love about their passive house;
  • Exceptionally quiet spaces that are isolated from outside noise, even during storms;
  • Less complex operational and maintenance requirements due to simpler mechanical systems;
  • Comfortable, conditioned fresh air in the living spaces through the use of high-quality ventilation equipment;
  • Increased safety and security during storms: even when power is out for weeks, a passive house will maintain temperatures above 50F (10C).
Financial Incentives Needed for Adoption

Providing financial incentives for the adoption of net zero passive house technologies will hasten acceptance by the marketplace and its adoption into the building code, and in our uncertain climate future, this is good public policy.

A net zero passive house is slightly more expensive to build, but excels in the total cost of ownership, a fact not always well understood. Hence, without some inducement, the higher up-front cost of net zero passive houses can present a disincentive to their adoption. Financial incentives can help to overcome this reluctance.

Research in North America shows that financial incentives are particularly effective in overcoming the public’s reluctance to switch to energy-efficient technologies such as the net zero passive house; Research in Europe showed similar findings—“financial incentives and energy performance standards play an important role in promoting energy efficiency improvements.”

It seems likely that increasing the energy efficiency of new and existing North American detached homes will require public intervention. A good first step is changing building codes to emphasize net zero passive house level energy efficiency. Such code changes will ensure that all new structures achieve significant and permanent energy reductions. These code changes should be accompanied by financial incentives to facilitate the transition.


Video: ‘Breathable’ Façade Makes Buildings More Energy Efficient?

Fri, 2020-02-14 15:19
Energy EfficiencyBuilding Science

Click to enlarge.

Barcelona’s Institute for Advanced Architecture of Catalonia (IAAC) has undertaken a project examining the benefits of hydroceramic façades as a means of cooling down buildings in hot countries. Known as “breathing” buildings, the technology uses an insoluble polymer called “hydrogel,” fabric as a water channel, and ceramics.

The hydrogel, it is claimed, can expand its volume up to 400 times when absorbing water. This, in turn, enables the panels to absorb humidity and allows it to evaporate—hence the likeness to breathing.

The IAAC claims the technology could help buildings slash their energy bills by a third.

Watch a video from IAAC’s Digital Matter Studio below.


Huber Settles ZIP Patent Dispute with RoyOMartin

Fri, 2020-02-14 15:10
Press Releases

Building products manufacturer Huber Engineered Woods achieved a negotiated settlement with RoyOMartin and Corrigan OSB in its patent infringement lawsuit against the companies. HEW’s lawsuit, filed in December 2018 in the United States District Court for the Eastern District of Texas (Huber Engineered Woods LLC v. Martco, L.L.C. and Corrigan OSB, L.L.C., Civil Action No. 2:18-cv-530), alleged the RoyOMartin Eclipse Weather Resistant Barrier product infringed on at least seven of HEW’s ZIP System sheathing and tape patents.

Adobe Stock

As part of the settlement, RoyOMartin has agreed to suspend sales of its Eclipse Weather Resistant Barrier products. The lawsuit will be dismissed as a result of the settlement, according to a news release from HEW.

“Our company has a long-standing history of providing innovative products, premium solutions and quality support to our customers and will continue to invest in upholding those standards,” HEW President Brian Carlson said in a news release.

The ZIP System sheathing and tape, introduced in 2006, is a structural panel with a built-in exterior weather-resistive barrier (WRB) that provides moisture protection and air sealing. The all-in-one system is designed to offer the same structural bracing as traditional sheathing combined with a WRB, saving buildings time and money on the job site.

“We are pleased to resolve the issue with RoyOMartin, and we will continue to defend and protect our brands and intellectual property portfolio as evidenced by our previously announced patent infringement lawsuit against Louisiana-Pacific Corporation,” added Carlson.

HEW filed a patent-infringement lawsuit against LP Building Solutions in February, claiming LP’s WeatherLogic Air & Water Barrier products infringed on at least eight of HEW’s ZIP System sheathing and tape patents. HEW filed the LP lawsuit in the United States District Court for the District of Delaware (Huber Engineered Woods LLC v. Louisiana-Pacific Corporation).