All Existing Homes
In July of 2015, EnergyLogic began informing you about upcoming software changes. As a reminder, the Residential Energy Services Network (RESNET) began to align the energy rating reference home to the 2006 IECC almost two years ago. The reference home, which currently reflects the 2004 IECC supplemental code, is what your home is compared to in order to create the HERS Index score. RESNET has gone through a process of taking the rule set for how to develop the HERS Index score through the ANSI process in order to create the ANSI/RESNET/ICC 301-2014 Standard for the Calculation and Labeling of the Energy Performance of Low-Rise Residential Buildings using an Energy Rating Index. The main impetus for this ANSI Standard arose from the desire to use the Index Score for code compliance and the adoption of the Energy Rating Index (ERI), a HERS path, as a compliance matrix for the 2015 IECC.
The alignment with the 2006 IECC has three primary effects on the HERS reference home.
- First, the updated 2006 IECC reference home infiltration rate became tighter to better reflect the improved tightness levels of newly constructed homes.
- Second, the updated 2006 IECC reference home window solar heat gain coefficient (SHGC) went from 0.55 in climate zones 4 through 8 to a SHGC of 0.40 in those climate zones. This updated value reflects the market penetration of improvements in basic window technology and is in alignment with the 2006 IECC.
- Lastly, revised mechanical ventilation requirements are used in the HERS reference home which are now aligned with the ASHRAE 62.2-2013 ventilation standard.
Scores to Increase by 2 to 6 Points
Philip Fairey, Deputy Director of the Florida Solar Energy Center and a consultant for RESNET, performed research on the impact of these changes on the HERS Index values of rated homes in all eight climate zones. His research has demonstrated that the HERS Index values will increase across all climate zones by a range of 2 to 6 points due to the reference home alignment with the 2006 IECC that occurred through the creation of the ANSI/RESNET 301-2014 Standard. EnergyLogic has been working with the newly released software, and we are seeing results that are consistently on the high end of the range (3-8 HERS Index points) when comparing homes that were rated with software developed prior to the ANSI standard adoption. RESNET is mandating that HERS providers begin using the new software on January 1, 2017. EnergyLogic has worked with RESNET to find ways to reduce the impact of the implementation of the ANSI standard software. A few things are, or have been, changed but the impact of the score increase will remain significant, affecting every home across the country.
Incorporating Water Heating
The development of the ANSI standard has also given RESNET the opportunity to include additional features related to water heating. This is specific to energy use related to hot water distribution and does not take into account water conservation. RESNET is working on a Water Index score that will address water conservation. The ANSI standard addendum allows the HERS Index score to quantify the efficiency or loss of energy through; pipe runs from the water heater to the farthest fixture, hot water pipes that are insulated, on-demand recirculation systems, high-efficiency low flow fixtures, and drain water heat recovery systems. If all of these systems are deployed in a home, the technologies can provide builders approximately 1-3 point reduction in the HERS Index.
It is important to also understand that if a builder is currently utilizing a water delivery system that is not delivering the hot water efficiently then the HERS Index would be penalized. For example, if you are currently using a timer or continuous recirculation loop to deliver hot water, your home’s HERS Index will be penalized. This will result in a higher score than the normal transition to the ANSI approved software. So, in this example, if the transitioning to the ANSI approved software took a HERS Index from 60 to 65, the inefficient hot water circulation system could add another 5-10 points, taking the score to 70 or 75. It is important to evaluate your current specifications and choose the most efficient water distribution systems, such as an on-demand hot water recirculation system, or stop installing them all together.
Summary: All Homes will Be Affected
These changes will affect every home that is rated but should have minimal impact on the use of the Index score for demonstrating compliance with programs such as EnergyStar, as the program’s energy Index target will fluctuate in unison with the home that is being rated. In the same way, these changes should have minimal effects on code compliance when utilizing the Simulated Performance path as the code reference home is separate from the HERS reference home. For those few builders utilizing the 2015 IECC Energy Rating Index path (ERI), these changes will be significant. Lastly, builders utilizing the Index score in their marketing efforts will need to update HERS related marketing collaterals.
Principal / Director of Builder Relations
The Q3 Field Fusion event delved into air-sealing and sound transmission challenges in multi-family units through a guided discussion that included perspectives from Code Officials, Insulators, and Raters. Read more here.
There are many complexities that accompany building townhomes and duplexes. For example, townhomes and duplexes built with common fire separation walls (party walls) are twice as leaky as single family houses that are twice their size.
The shaft wall, which we see most often in Colorado, is open directly to the outside through the designed gap between the shaft liner and the framing, thus creating a leaky assembly. An additional complexity arises when the reduction of unit-to-unit sound transmission is taken into account, which requires correctly installed insulation.
EnergyLogic’s August 31st Field Fusion delved into the details of these assemblies through a guided discussion that included perspectives from Code Officials, Insulators, and Raters.
We must first define what part of the shaft wall assembly is fire-rated, as the entire assembly is not. This is an important distinction that allows for more air sealing options once understood.
In chapter 3 of the IRC, Section R302 “Fire Resistant Construction” and Section R302.2 “Townhouses” states, “The common wall shared by two townhouses shall be constructed without plumbing or mechanical equipment, ducts or vents in the cavity of the common wall. The wall shall be rated for fire exposure from both sides and shall extend to and be tight against exterior walls and the underside of the roof sheathing.”
This statement in the IRC is our first indication that the two layers of sheetrock in the shaft liner wall are the fire-rated two-hour wall, designed to slow the spread of fire from unit to unit. Thus, the two layers of 1” drywall cannot be penetrated with ducts.
The framing (which is held off the fire-rated assembly by a clip) often has ducts or plumbing in it and is specifically designed to burn and separate from the two-hour assembly when the clip melts. This allows one unit to burn and fall before fire is able to pass through to the adjacent unit. The UL (Underwriters Laboratory) listing for many of these assemblies’ references section 705 of the International Building Code (IBC) which states in Section 705.2 “Structural Stability”, “Fire walls shall have sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall for the duration of time indicated by the required fire-resistance rating.” This is another indication that UL listings and the code are in agreement that the fire assembly is the two layers of 1” drywall and not the framing adjacent to the drywall.
It is important to point this out because throughout Colorado there is not a common understanding of what constitutes a shaft liner fire-rated party wall assembly. Some jurisdictions still hold that the assembly is the drywall, air gap, clip, framing and interior drywall while others hold that it is as explained above. What is consistent is the understanding that the assembly must be built continuously from the foundation to the roof deck.
EnergyLogic suggests having a discussion with jurisdictions, in an effort to:
- Ensure a common understanding of this assembly
- Determine how the assembly will be air sealed to control airflow to meet the air leakage requirements of the energy code.
One thing to note: jurisdictions throughout the state require that the two layers of sheetrock run continuously from the foundation to the roof deck, but not the entirety of the rest of the assembly. The most conspicuous example is the interior drywall, which is always missing on the ventilated attic side of the party wall.
Challenge: How to Achieve 3 ACH50?
Now that a common understanding of the assembly has been achieved, it is time to determine how the assembly can be air sealed in order to meet the air leakage target of 3 ACH50 for the 2012 and 2015 IECC. Most jurisdictions have not amended the requirement to meet this airtightness level, so pre-planning is crucial in order to be successful.
The clip that holds the framing off the two-hour party wall assembly creates a 1” gap that is connected directly to the outside at the front and back of the unit, as well as to the attic. This is where the UL listing of the assembly comes into play. UL is an American safety consulting and certification company that provides the one or two-hour rating for fire-rated assemblies by testing them in a laboratory environment. The UL listing for these assemblies is often mixed up with code’s definition of the assembly, which creates confusion regarding what materials are allowed to be used to seal them.
UL often refers to fire-blocking materials. Fire blocking materials are usually defined within the UL assembly and can be any one of the following:
- 2” nominal lumber
- Two thicknesses of 1” nominal lumber with broken lap joints
- One thickness of 0.719” wood structural panel with joints backed by 0.719” wood structural panel
- One thickness of 0.75” particleboard with joints backed by 0.75” particleboard
- Gypsum board, including 1” DensGlass Ultra® Shaftliner and 5/8” DensArmor Plus drywall
- Batts or blankets of mineral wool or fiberglass
- Other approved materials installed in such a manner as to be securely retained in place shall be permitted as an acceptable fire block (Section 717.2.1, 2006 IBC).
As some fire blocking materials are air barriers and some are not it important to choose a material that can stop the flow of air. EnergyLogic has seen the most success when builders tackle fire blocking on each individual floor.
Application: The Picture Frame Method
When looking at the party wall assembly, envision a picture frame around the perimeter of the wall. All four sides need to be fire blocked. The material of choice right now is the same 1” gypsum board used in the 2-hour rated assembly. Install the 1” gypsum board in the 1” gap between the interior of the unit and the outside at the front and back of the units, between floors, and to the attic. Again, picture framing the party wall.
Depending on your foundation type, if you are standing on the first floor you will need to air-seal the two layers of gypsum and the bottom plate to the slab in the shaft wall, or address the rim joist connection in the basement or crawl space to the shaft wall. At the rim joist be sure sill seal has been installed between foundation and sill plate as it is your primary capillary break, then seal the sill plate to foundation, seal rim board to the sill plate, and seal the rim board to sub floor. Pay special attention to any knockouts for foundation bolts.
Once the large 1” gap has been fire blocked with an air-impermeable material such as gypsum, seal the smaller gaps between the fire block and the shaft wall and the fire block and the framing. A fire-rated caulk or expanding foam works for this. Following these steps, with careful attention to detail, should enable you to successfully achieve 3 ACH50.
A few words of caution:
- Ensure that the drywall lid is air-tight: duct boots and other penetrations need to be sealed. In addition, as required by ENERGY STAR, the drywall to top-plate should be sealed. (This is a requirement of code that is generally not enforced.)
- Mechanicals can derail all good air-sealing intentions. Undampered ducts run to the exterior for combustion or ventilation air as well as atmospherically vented appliances. These combustion air ducts can ruin one’s ability to build a tight home that gains control and predictability of the airflow in the building.
Don’t Forget: Sound Reduction
Lastly, these assemblies should reduce sound transmission from dwelling unit to dwelling unit. The party wall is assumed to be an adiabatic wall, i.e. there is no heat loss or gain through the wall between two conditioned spaces as the temperature is the same on each side. Therefore, the insulation is primarily installed to lower sound transmission. The principles of sound reduction and heat flow are the same, so proper installation of the insulation in the framed cavity of the party wall is imperative.
NAIMA, the North American Insulation Manufacture Association, states that the installation of insulation in a party wall application should “comply with the manufacturers’ instructions including filling the entire stud cavity and cut to fit around outlets, junction boxes, and other irregularities in the cavity.” In other words, the insulation in a common party wall should be installed to a RESNET, Grade 1.
To learn more please see EnergyLogic’s Tech Bulletin on “Fire-rated Party Walls” which includes an article by Building Science Corporation.
Have a technical question? Contact Robby Schwarz.
Our next event will take place on November 16th. It is focused on Selling High-Performance Homes. Our guest speaker, Todd Gamboa, President of Building Trust LLC., has a wealth of experience and perspectives to share. Please see details here.
If you have suggestions for topic you would like to see discussed in depth, please let us know. We will be releasing our Q1 2017 event topic and date soon.
Principal / Director of Builder Relations
Get in the Game by Selling High Performance
3:00 – 5:00 PM
Presenter: Todd Gamboa, President of Building Trust LLC
5:00 – 7:00 PM
EnergyLogic’s Mixer and networking
Drinks & hors d’oeuvres provided!
Todd Gamboa, President of Building Trust LLC, has been in the building industry for over 30 years, managing private and public companies. As a homebuilder, he has been responsible for the creation of thousands of homes. As a building science consultant, public speaker, and host of “New Home Solutions Radio”, he educates homebuilders, contractors, architects, appraisers, and realtors all over the country about the value and benefits of buying new construction. Mr Gamboa has launched and managed several, energy efficiency and “market transformation” programs for utility providers; home builder and realtor associations; and state and federal government agencies throughout the U.S. His fast-paced, fun, and informative sales training have been described as “Info-tainment” by attendees.
This Field Fusion event is generously supported by Tyvek.
EnergyLogic is proud to announce some exciting changes to our team! Get to know our new Field Services Manager & Software Technical Liaison, Steve Eagleburger.
Q&A: Learn more about Steve, his comprehensive background, and credentials!
What was your first job in the residential construction industry?
I’ve been involved in construction most of my life. I started as a painter/faux finisher around 30 years ago. I moved on to handyman work and eventually became a General Contractor around 2003.
How and when did you first become interested in high-performance homes and energy efficiency?
I’ve always been interested in environmental construction and design. I built the one and only Compressed Earth Block home in Denver and currently live there. It’s imperative that the construction industry realizes the impact it has on this planet and its inhabitants and take steps to move toward more efficient, cleaner and safer homes.
What insights did you gain in your time working as a general contractor?
Contractors can change the way we build homes and by making that change we can create longer- lasting, more comfortable, better performing homes. We often are focused on the bottom line when we should step back and look at the big picture. Success comes when we meet a triple bottom line -Economic Value, Environmental Sustainability and Social Responsibility. This is what drove me as a G.C. and eventually what lead me to work at Energylogic.
You’ve been with EnergyLogic since 2010 and have worked at a number of different roles. What are some things you can share about your background in residential energy consulting?
You don’t know what you don’t know until you know it and as soon as you know it you need to share it. This is a constantly evolving industry and as raters and builders, we have to stay informed. Codes and programs evolve over time. It’s our responsibility as energy consultants to keep our clients informed and be as pre-emptive as possible when change is coming. Nobody likes surprises!
What are some of the common design mistakes or misconceptions builders should watch out for?
Demand a detailed set of drawings from your architect and engineer before you start to build and make sure those drawing specify local codes and builder program details! Refresh your plan set to include updated codes or details that were missed originally so you don’t keep repeating the same mistakes. So many failures and re-inspections can be avoided by having a knee wall framing detail somewhere in your plan set, or air barrier detail drawn for double framed walls, or by making sure there’s room between the stairs and foundation wall to add insulation, etc. These details allow everyone to do their job better, from estimators to installers.
Little things do matter. Even though we don’t like to delay construction schedules over minor issues, small improvements on a national scale can make an impact. We call these things out to help you build a better product, not to be obstructive. The building code and national programs such as Energy Star and DOE Zero Energy Ready Homes exist to help you build a better product and get to that triple bottom line. Embrace it and accept the future of construction!
What do you like to do in your free time?
When I’m not working you’ll find me hiking or camping with my wife and dog, but nothing too extreme. We like the quiet places. Or maybe I’m down at the local brewery for a pint of cask-conditioned English ale. Once a week you’ll find me at Zenko Kyudojo in Boulder, practicing Japanese archery.
EnergyLogic Academy’s Referral Program Rewards – Tell ALL Your Friends!
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Let’s keep building this industry – together!
RESNET HERS® Rater Training Combo Package (Phase 1 & 2)
Phase 1 of the EnergyLogic Academy HERS Rater training is designed to allow participants to navigate through the knowledge base needed for a HERS Rater at the users own pace. The course prepares students for the extensive knowledge needed in building science, building materials, integrated construction processes, HVAC equipment, and diagnostic testing equipment and processes.
The HERS Rater Training online course covers the core knowledge for the HERS Rater certification. By enrolling in our self-paced, open enrollment course, you will have 90 days to complete the training. You can complete the training at your own pace, and you do not need to use the whole enrollment period if it is not needed. There are 24 modules in the course – each module will take a minimum of two hours to complete, with some taking over four hours.
Phase 2 is four days of field training designed to introduce the HERS Rater inspection processes and diagnostic testing. During the field training, we will complete two practice ratings according to the RESNET training standard. Practice ratings will be performed on an existing home and a new home.
This is an instructor-facilitated course. Students will have one-on-one instruction with the testing equipment. Much of the field work will be done in a group setting, where peer-to-peer interaction is used to complete the practice ratings.
RESNET® Instructor, Green Rater, Auditor
Field Services Manager & Software Technical Liaison
After completing the course, Rater candidates have two steps remaining before earning certification:
The candidate must pass three exams. The exam fees are not included in the price of tuition. These fees are paid directly to RESNET. For more information click on the RESNET Exams tab.
The candidate must join a provider and complete the probationary phase of certification. The provider ultimately issues the certification once the candidate completes the probationary phase.
A package you just can’t turn down!
Use coupon code december2016 for $500 off of the HERS Rater Training Como
I’ll admit, when I first began auditing I performed the obligatory utility info analysis on a home as a required part of the audit without reading into it. I printed the graphs, handed the sheets to the homeowner, explained a couple things and moved on to testing and measuring insulation. Looking back I realize how naive that was. Right before me was a great tool not being utilized, the utility bill! The one day, I handed over the keys and let the utility info take the wheel of my audit instead of the other way around.
The first step was realizing how useful it could be. I had a day, an audit, an example, that opened my eyes. I walked into the homeowner interview and asked, “Why the audit?” They responded with “Increased utility bills over the past 18 months and a warm house in the summer.” I assumed I’d be looking for the usual suspects. Then I entered the utility room, knelt down in front of the water heater and observed a recirculating pump. I’ve seen this before so I asked the homeowner when it was installed. The answer was less than two years ago. His plumber told him that the recirculating pump would help to make the house more efficient. I suppose this may have reduced water run time while waiting for warm water to reach the shower, but this wasn’t evident on the utility bills.
While putting together the report it hit me like a bug splatting on the windshield. It was right there in front of me before I even knocked on the front door. I saw an increase in water heating energy use following the install of the new water heater. The increased water heating load added another small monthly amount to bills. Then I pulled out my infrared camera and began pointing it at interior walls. Low and behold I was looking at warm wall cavities where the plumbing lines ran through the house. During the summer this warmed the house and caused the air conditioning to run more. With tiered rates in place during the peak use summer months this bumped up the bills even more.
Now, we haven’t emptied the tank getting more insight from the utility bills just yet. It turns out they are extremely useful when prioritizing recommended improvements and creating a simple return on investment. I’ve learned that most homeowners equate efficiency with lower utility bills. You can’t ignore this when making recommendations. Take for instance; installing a high efficiency furnace when the heating energy use is already low. If they don’t currently spend much money heating the house this will make the payback stretch further out. It’s hard to save 20%-30% on heating bills when your BTU’s per square foot are already low.
It’s best not to lose sight of one of the reasons we are in the house to begin with… to lower utility bills. Although there are many other components to a Home Efficiency Audit, they all need to fit together nicely to produce optimal results.
- Brad Smith
- EnergyLogic Rater and Auditor
My neighbor, “Bob”, invited us over for a beer to proudly tell me how he had signed up to have an energy audit performed on his home and he recognized our company name, EnergyLogic. The reason for the audit? His energy bills have been very high and he has decided to get solar installed; the audit will qualify him for some additional rebates.
I couldn’t resist … “Tell me a little bit about what you’re getting done?” I asked him. He was very excited to describe how helpful the solar company had been to do all the work to analyze his bills, design a system to meet his current needs, do all the paperwork for the federal rebate (that went directly to them to help reduce the cost of the system) and to work out all the financing with the utility that would bring his average electric bills down from $250/month to a fixed rate of only $180 … for the next 40 years.
I tried not to sigh too loudly or garner the stink-eye from my wife, but I just had to ask, “So, what are the putting in?”
“A 16kW system,” he replied. “Just 4kW short of commercial grade.” He seemed almost proud, as if the solar sales person had convinced him this was a good thing.
Ugh … here comes the stink-eye. I’d better hold my tongue.
Bob’s a pretty smart guy – he owns his own business, he has an engineering degree and I’ve always found him to be pretty thoughtful about things. However, this seems like signing up for chemotherapy because you aren’t feeling well, and then making the appointment to see your doctor.
Don’t get me wrong – I’m not against solar (or chemotherapy) – when it makes sense, but to go down that path without first having a full check-up performed seems a bit ill-considered. I can’t fault Bob so much, I think he was duped by one of the less scrupulous solar sales people. After all, why would they recommend an audit before they did the specifications for the system and had a signature on the dotted line? What if they lost the sale?
I can understand after-the-fact audits (to qualify for rebates) in situations like a furnace that has stopped working or some other time-sensitive event. But it still baffles me that utilities and others allow such expensive and questionable work to be performed and the homeowner will still qualify for the rebates before having an audit performed.
Back to Bob – With such an investment already underway I tried to choose my words carefully. I told him our auditors could probably make some additional efficiency recommendations he should consider. They would likely help decrease his actual energy use whereas the solar system was merely controlling the cost. Unfortunately, my genteel way of saying, “You did this backwards,” was not lost on Bob and I could see the look of dread on his face. On the bright side, I enjoyed the free beer and at least for a moment, Bob wasn’t too mad. What else can you do?
Quite often I step backward and look outside the badge of a BPI auditor and put myself in the shoes of a homeowner. A homeowner whose home I’m about to pick apart. For the most part homeowners are happy to have us there. We’re there to help, not to sell. They expect us to make recommendations telling them what should be improved. They expect, “Fix or replace this, and your house will be better.” What they don’t expect is the education that comes with it. With an understanding of how these recommendations make a difference, homeowners could save thousands.
On a recent assessment of a home I was told the main interest in having an audit was to confirm the need to replace an induced draft furnace with a sealed combustion furnace. The homeowner was replacing a sensor that was failing every few months. An HVAC contractor suggested buying a sealed combustion furnace. Ta Da! Problem fixed. Not so fast.
It should be noted that the furnace was located in the crawl space; and a vented crawl space to boot. This was a big factor in several issues, one of which was the routine replacement of the sensor, the comfort in the rooms above the crawl space and poor indoor air quality. The thinking was that the sealed combustion furnace would reduce or eliminate the likelihood that the sensor would need to be replaced often and that the air flow would be better to the rooms above, increasing comfort.
As you know, a new furnace doesn’t address the root of the problem. This is where educating the homeowner is valuable. We need to make sure they understand why we recommend the improvements we do. We sat down to discuss why the problems existed in the first place and how a new furnace will still leave them with their current problem.
First, let’s look at the sensor problem. The dry, dry dirt in the crawl space was being pulled into the furnace housing and collecting on the sensor. What he needs is to install a sealed barrier over the ground of the crawl space, preventing premature failure of the furnace. More importantly, this would improve indoor air quality. Next was to address the comfort issue in the floor above the crawl space. With a new furnace and increased air flow to rooms, the vented crawl space would still allow cool air to directly impact the floor above. To truly fix this would be to seal the crawl space vents, air seal and insulate the rim joist and insulate the walls. This was an easier fix and less expensive than replacing the furnace. The homeowner understood and agreed, then decided to pursue improving the crawl space.
In the end, recommendations for improvements are a lot more beneficial if the homeowner has basic understanding of the science behind those recommendations. Too bad there is not a Cliffs Notes of basic building science for homeowners.
I recently had the distinct pleasure of being one of six judges @ the America’s Best Installer Contest sponsored by Johns Manville and Insulate America. Twenty four of the best insulation installers from around the country descended on Denver to compete for the $10,000 top prize.
Having inspected a few thousand insulation installs, I thought I had a pretty good idea of what I was going to see at this competition. I have long believed that quality and speed are opposing forces with regards to insulation installs. The amazing thing about these installers is that they are able to combine the two. Congrats to Nicholas Forehand of Orchard Park, N.Y.-based Northwind Insulation, who was “America’s Best Insulation Installer” of 2013!
Insulators are the unsung heroes of new home construction and I am very thankful to the sponsors for helping bring them the credit they so richly deserve.
Are you a rater, auditor, or installer who is thinking of advancing your career by obtaining a new credential? It’s been said that our industry has caught a case of certificationitis. And it is true that there have been a lot of new certifications within the last year or so. So how do you make sense of it all? Read on.
I received a large envelope in the mail recently. It was from the Building Performance Institute, informing me that I have been awarded the new Quality Control Inspector certification. BPI does a really good job when they award certification- including a letter, a nice color certificate, ID card, and even some BPI patches if you want to create your own swag. So, you can imagine that I was feeling a little bit of pride. But then, someone asked me to explain in plain terms what this would allow me to do and how it would impact my job.
I thought for a minute. As I did so, the wind in my sails subsided. The short answer is, absolutely nothing. At least in the short term, I won’t be doing anything any different than I was already doing. There is no new work out there for me, no new program that I can participate in today that I couldn’t already participate in. So why did I bother to obtain this new certification? I’ll get to that. First, I thought it would be helpful to outline some of the new credentials out there, how you obtain them, and how to determine if they would benefit your…