All Building Science

New Home Builder Rebates are increasing, in a good way!

New rebate structure update and highlights of the Xcel Energy ENERGY STAR® New Homes Program 2016 accomplishments.

Total year-end program results from 2016:

  • 5,300 total completed houses
  • 145,835 net Dekatherms and 4,957,801 net kilowatt-hours in energy savings
  • $3,361,890 in builder rebates and energy rater administrative fees
  • 1,800 earned the $100 ENERGY STAR rebate

Program and Rebate Changes for 2017/18, effective for homes submitted after March 1st:

  • Homes will qualify for rebates based on the percent improvement better than the local adopted IECC code
  • Rebate levels are increased for homes built in jurisdictions where IECC 2012 and newer codes are enforced
  • The $10 ENERGY STAR dishwasher rebate is discontinued and the clothes washer rebate is reduced from $50 to $30
  • The High Efficiency Lighting rebate is unchanged for homes built in jurisdictions where IECC 2009 and older codes are enforced
  • For homes built in jurisdictions where IECC 2012 and newer codes are enforced, a $10 rebate is available if 100% of lighting is CFL or LED fixtures and/or bulbs
Percent Better Than Local Code Improvement Builder Rebate – IECC 2009 and older Builder Rebate – IECC 2012 and newer
10.0 – 14.999% $200 $250
15.0 – 19.999% $350 $400
20.0 – 24.999% $500 $600
25.0 – 29.999% $650 $900
30.0 – 34.999% $800 $1,300
35.0 – 39.999% $1,000 $2,000
40% and higher $1,400 $2,550

 

Appliance/Lamp Builder Rebate – IECC 2009 & older Builder Rebate – IECC 2012 & newer
Refrigerator $10 $10
Clothes Washer $30 $30
Lighting Efficiency (CFL or LED) $20 (20+ qualifying bulbs) $10 (100% qualifying bulbs)
ENERGY STAR®, Xcel Gas & Electric $100 $100

Tracy Larson

 

Who to Contact:

Tracy Larson
Logistics/Customer Support Supervisor

Email Tracy
970-556-6491

Important RESNET® Amendment on Rating Software Changes (Persistence)

RESNET Adopts Standard Amendment on Persistence of the Use of Previous Versions of HERS Software When Standards Change

The latest release of Rating software, represented by the new ANSI/RESNET/ICC 301-2014, has dramatically demonstrated an issue that has been apparent for quite some time. To further expand on how various software versions impact changes to HERS Index scores, and how the recently adopted amendment, effective February 16, 2017, applies, please review the following:

  • When standards and software are updated, the HERS Index score can change.  In the case of ANSI/RESNET/ICC 301-2014 the score change is dramatic.
  • As the HERS Index continues to grow in our national vocabulary, consistency of the scoring system becomes increasingly important.

As the standards are currently written, homes in a community with a buildout of twenty years can use old software because software does not have to be updated due to the notion of “Persistence”. If left open to interpretation, one Projected Rating could be applied to multiple building permits in production housing, allowing “Persistence” based on a Projected Rating to extend the use of older software versions to 5, 10, or even 20 years.

After the RESNET Standard Public Review and Comment process, the RESNET Standards Management Board has adopted Amendment #2017-01.

  • The amendment requires that “Confirmed or Sampled Ratings on homes with a building permit date that is on or after the six-month anniversary of the release of the software must utilize the newly released software.
  • Homes with a building permit date before the six-month anniversary of the release of the software will be allowed to complete a Confirmed or Sampled Rating based on the previous version of the software that was utilized for the Projected Rating.”

The amendment also allows the RESNET Board of Directors to stipulate a timeframe other than the six-month anniversary of the building permit date.  The RESNET Board of Directors has not used this clause to date.

The adopted amendment is posted at RESNET Standard Amendment #2017-01

The amendment goes into effect on February 16, 2017.

Link to related article: HERS® Rating Scores Going Up

Robby Schwarz

 

Who to Contact:

Robby Schwarz
Principal, Director of Builder Relations

Email Robby
720-838-0677

Energy Logic – All Homes Will Be Energy Efficient

all-homes-will-be-energy-efficient-robbyschwarz

EnergyLogic is in the news! Check out this interview with Robby Schwarz, one of the founders and continuing principals here at EnergyLogic. You’ll find the article supporting how EnergyLogic continues to help builders, salespeople, and consumers in our industry better understand the long-term benefits that energy efficiency will bring to their lives.

To access the article, please click on the link below:

Northern Colorado ENERGY STAR® Article

 

Robby Schwarz

 

Who to Contact:
Robby Schwarz
Principal, Director of Builder Relations

Email Robby
720-838-0677

HERS Energy Rating Index Scores are Going Up!

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.

Effects

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.

Robby Schwarz (faked)

 

Robby Schwarz

Principal / Director of Builder Relations

EnergyLogic, Inc.

720-838-0677

Contact Robby Schwarz

Field Fusion Recap: The Disconnect Between Fire & Energy Codes

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.

Why?

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.

Clarification: What Part of the Shaft Wall Assembly is Fire-rated?  recap-of-ff-image_1

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.

recap-of-ff-image_2

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). recap-of-ff-image_3

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.

recap-of-ff-image_4

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.recap-of-ff-image_5

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.

Robby Schwarz (faked)

 

Robby Schwarz

Principal / Director of Builder Relations

EnergyLogic, Inc.

720-838-0677

Contact Robby Schwarz

Field Fusion: Learning How to Sell the Benefits of High-Performance Homes

Get in the Game by Selling High Performance 

Field-Fusion-LogoDate: November 16, 2016
3:00 – 7:00 PM

Cost: None

Location: Tavern Tech Center (Upstairs) 
5336 DTC Blvd
Greenwood Village, CO 80111

Please RSVP here

Event Logistics:

3:00 – 5:00 PM 

Presenter: Todd Gamboa, President of Building Trust LLC

Issue: New construction is on the rise again. However, the real estate market is still dominated by older homes as they represent over 85% of sales. Homebuilders, HERS® Raters, trade partners, suppliers, and manufacturers have a significant impact on the way new homes are designed, built, and sold.
 
Objective:  Converting prospective buyers to new construction is a team effort. Leveraging your knowledge of building science, energy efficiency, and consumer trends and behavior, is the most effective way to create opportunities. Get in the game by learning how to demonstrate and sell the benefits of high-performance homes, services, and products. You will increase your sales, improve your profitability, and differentiate your brand!

5:00 – 7:00 PM 

EnergyLogic’s Mixer and networking

Drinks & hors d’oeuvres provided!

Todd Gamboa

todd-gamboa

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.

 

Get to know our new Field Services Manager & Software Technical Liaison, Steve Eagleburger

steve-eagleburger-serious-for-ela

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.

 

RESNET HERS® Rater Online & Field Training December 5-8, 2016

$500 Discount for Online/Field Combo Students!

Click here to register

Use coupon code december2016 for $500 off of the HERS Rater Training Combo

EnergyLogic Academy’s Referral Program Rewards – Tell ALL Your Friends!

We feel everyone should benefit from ‘word of mouth’ marketing, not just us! We make it worth your while by offering cash rewards through our referral program.

Earn up to $100 cash per referral

Let’s keep building this industry – together!

RESNET HERS® Rater Training Combo Package (Phase 1 & 2)

PHASE 1 – ONLINE & SELF-PACED 
Start Today! 

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 – FIELD TRAINING 
December 5-8, 2016
Denver, CO

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.

 

INSTRUCTORS: 

ben-for-ela

 

             Ben Graham

             RESNET® Instructor, Green Rater, Auditor

 

 

steve-eagleburger-serious-for-ela

 

          Steve Eagleburger 

          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!

Click here to register

Use coupon code december2016 for $500 off of the HERS Rater Training Como

 

Introducing our new HVAC Designer, Scott Olson

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Introducing our new HVAC Designer, Scott Olson

Q&A: Learn more about Scott, his design philosophy, background, and credentials!

What was your first job in residential construction industry?

Construction Superintendent for a National Home Builder in Denver. The Job consisted of front and back‐end scheduling, and warranty work.

How and when did you first become interested in high performance homes and energy efficiency?

While working for a local home builder, I helped create their High Performance testing on all homes. I received my Residential Energy Services Network (RESNET) Certification and tested homes for energy code compliance and made sure homes were ENERGY STAR compliant. I balanced the needs of a production builder with ENERGY STAR best practices.

How did you get into HVAC Design?

I was challenged by my boss, while working for a large production builder, to take on a whole new role as an HVAC Designer. My construction experience as a superintendent was a huge advantage and I strived to make my designs be trade friendly and cost-effective.

What insights did you gain on HVAC designs when you worked directly for a large production builder?

Designed cost effective, construction friendly and functional HVAC systems

What elements of EnergyLogic’s HVAC design philosophy resonated with you and attracted you to the job?

EnergyLogic’s HVAC design services, with a goal of ensuring comfort and efficiency with properly built envelopes integrated with properly-sized and designed HVAC systems.

What are some of the common design mistakes or misconceptions builders should watch out for?

Sizing HVAC with a rule-of-thumb calculation. With today’s tighter building envelopes, rule of thumb often results in oversized systems that cost more upfront and cost more to operate over time. Oversized systems also don’t dehumidify as well as properly sized systems because the run time is shorter, so occupants are actually paying more for discomfort. 

What do you like to do in your free time?

In my free time, I enjoy grilling, working on projects around the house, and camping.

IECC and Multi-Family Buildings

Exterior Image

Up and down the front range of Colorado we are seeing more and more code jurisdictions adopt either the 2012 or 2015 IECC.  From a building science perspective, this is a step forward toward better performing buildings because these two codes require mandatory air leakage targets be met by all segments of residential construction three stories or less.  What I mean by this is that the code understands the importance of gaining control and predictability of the air flowing through our buildings.  I like to say that air is a freight train and like a train it carries cargo from point A to point B. The cargo it carries is heat/energy, moisture, and pollutants. The issue is that air does not always carry its cargo in a straight line on tracks from inside a house directly outside the house and deposit its load into the ambient air. A properly ducted fan may take air and its cargo to the outdoors, but often air takes its cargo into building assemblies and deposits it there, causing long-term building durability and efficiency issues for our homes. The code now recognizes that tight homes increase durability and efficiency and now understand that visual inspection itself cannot ensure house tightness.  The fundamental change in the code from the 2009 IECC to the 2012 or 2015 IECC is this recognition and the move from a choice to administer a blower door test or visually inspect to a mandate that you visually inspect and test to ensure tightness of the homes we build.

EnergyLogic tests homes and has been helping builders use the Simulated Performance pathway through code since the 2006 IECC.  Unlike other pathways in the energy code, the flexibility gained in the performance path allows for the most cost-effective means to develop the energy specifications for a house because we can trade off house tightness for R-values and U-values in the thermal envelope. This means that we understand that there is absolutely no problem achieving the code required 3 air changes per house at 50 Pascals (3 ACH50) in a single-family home.  In fact, the 2012 and 2015 IECC offer a checklist for how to be successful in the mandatory air barrier and insulation table R402.1.1.  We also know with certainty that it is not easy for multi-family buildings to achieve this same air leakage target. Currently, code does not recognize the difficulty of achieving 3 ACH50 in multi-family homes and buildings.  The City of Denver has accepted EnergyLogic’s code amendment to allow multi-family homes and buildings to have a leakage rate of 4ACH50. The city of Fort Collins allows a CFM/sqft of shell area measurement to be used to express air leakage in multi-family project.  So far they are the only jurisdictions in the state that I am aware of that have amended this section of the code to better reflect the realities of creating airtight multi-family buildings. On a national level, EnergyLogic has submitted a code change proposal for the 2018 IECC that makes a clear distinction between single-family detached homes and multi-family attached homes with achievable air leakage targets for both. We will have to wait until October to see if the proposal is accepted.

So where does that leave our multi-family builders?

Whether you are building duplexes, townhouses, or stacked multi-family buildings, house tightness is solely dependent on attention to detail with regard to air sealing adiabatic common fire rated walls, floors, and ceilings.  We recommend beginning by removing all draft-stopping materials (rock wool and fiberglass that are air permeable) in these fire rated assemblies and replacing them with solid fireblocking materials that actually stop the movement of air. By doing this you now have reasonable-sized holes that, depending on the jurisdiction, the assembly, and the skill level of the air sealing contractor, can be sealed. Next, you must treat common walls, floors, and ceilings as you would treat assemblies that separate conditioned space from the outdoors. The codes air barrier and insulation mandatory table/checklist must be applied to these common fire rated assemblies. For example, if there is a tub or shower pan, drop ceiling, or knee wall adjacent to an adiabatic common fire rated wall, floor, or ceiling, an air barrier needs to be installed.  Lastly, these details cannot be an afterthought!  They need to be addressed from the first design charrette, through a trade partner kickoff meeting, to mid-phase air barrier and insulation rough quality assurance inspection, if there is to be any hope of achieving 3 ACH50 when the home is blower door tested at a final inspection.  Blower door testing occurs when the home is complete and when it is impossible to achieve significant air sealing objectives at this point of construction.  Small changes in the tightness of the home may be able to be achieved, but air takes the path of least resistance; so if you have not blocked and sealed it out behind the drywall it is unlikely that you will be able to do more that achieve a small increase in the tightness of home at a final stage of construction.  In other words, the work has been done at the time of the rough inspection and the evaluation of the work is done at the final inspection.

In conclusion, get involved and take full advantage of EnergyLogic’s third-party inspection and testing services.  Get us involved as early as possible in the design of your multi-family project, and let us train all your trade partners at a kickoff meeting, how to successfully work toward meeting the requirements of code.  It is not easy, but attention to detail, quality assurance inspection, and greater understanding by the trade base will make 3 ACH50 achievable.

 

Robby Schwarz

 

Who to Contact:
Robby Schwarz
Principal, Director of Builder Relations

Email Robby
720-838-0677