Author: Brett Little

Embodied Carbon / Upfront Carbon / Embodied Energy, call it what you will, is the energy and carbon all burned up and used before the newly built home or renovated home even started operating. As operating energy starts to go down (aka your utility bills) with electrification, heat pumps, solar, and renewables on the grid, it is clear embodied carbon will make up the vast majority of carbon now emitted for new homes, buildings or remodeling projects. It is important we tackle this growing concern in an effective way, but how do we measure it?

 

Our GreenStar Homes Certification program is one of the first green building programs that requires new homes to have their embodied carbon reviewed in the Certified level and also reduced in the Silver, Gold, and Platinum levels.

 

We offer different tools and guidance on how to do this with the measure’s details here.

However, I know the industry is overloaded with so many tools. What if we had an all-in-one unified tool for home energy ratings, scores, carbon, and embodied carbon?

 

That is why we are excited to see the industry’s leading Home Energy Rating System open up public comment to add embodied carbon to it.

 

Imagine if when the rater did your preliminary rating, it could also provide your projected embodied carbo,n and you could make informed design decisions about how to change your product selections to get the best trade-off of lower embodied carbon, lower operational carbon, and lower utility bills all while complying with your needed HERS rating for code, green programs, utility funds and or IRA tax credits.

 

Well, we are getting closer to that reality!

 

“RESNET® releases draft PDS-01 of RESNET 1550, Embodied Carbon, for public review and comment. The standard provides a consistent methodology for the calculation and reporting of the embodied carbon of dwelling and sleeping units. The standard defines the scope for calculating embodied carbon and a methodology for conducting the calculations that uses the same modeling data and processes and reporting employed by standard ANSI/RESNET/ICC 301. Comments will be accepted only on text in draft PDS-01 shown by strike-through and underline and in red print. To review and comment on the Draft follow the links below. The public comment period begins November 22, 2024, and ends January 21, 2025.”

Please comment here with your thoughts and help make this a beneficial reality so we can transform the housing sector and make homes, BETTER.

Saving water is important; however, when it comes to total home health, we also need to consider more than water quantity in green.

A point-of-use reverse osmosis (RO) system is designed to filter water at a specific location, like under your kitchen sink, using pressure to push water through a semi-permeable membrane. This process removes various harmful contaminants such as lead, PFAS, bacteria, and viruses. While these systems are great for improving water quality, they do waste a significant amount of water—often five gallons or more for every gallon treated. However, models labeled with WaterSense are more efficient, producing just 2.3 gallons of waste per gallon of treated water.

 

Though the water from public suppliers in the US is generally safe, some people may want extra treatment, especially for well water. WaterSense doesn’t endorse RO systems for every situation, as other methods, like filtration, might be enough and waste less water. For those considering a new RO system, WaterSense-labeled models can save over 3,100 gallons per year, leading to substantial water savings nationwide.

 

Performance-wise, WaterSense systems are certified to meet specific criteria, ensuring they effectively reduce contaminants and maintain the membrane’s lifespan. The EPA has established specifications for these systems, which will be discussed at an upcoming virtual public meeting on Dec 17th: register here.

While most of the residential green building programs disregard RO and do not award for it or consider it, the GreenHome Institute GreenStar Homes Certification requires water filtration at the Gold level of our certification or for the Healthier Home badge. Go here to learn about what is required and get educated on why we can’t just think about air quality but also must think about water quality for total home health. The GreenStar program’s Home Water Score calculator was recently updated to be more accurate for projected water usage. What’s your Home Water Score for your home or latest project?

What if we added insulation on every re-siding job?

 The “doing this while doing that” concept is one of the best incremental ways to advance sustainability in existing homes. For example, when replacing water fixtures, get low-flow WaterSense certified; when upgrading appliances, go quiet, select ENERGY STAR certified appliances and switch to all-electric; and when needing a new A/C, opt for a Heat Pump instead, which can be standalone or paired with an existing gas furnace.

 Now, a new movement is well underway, led by the US Pacific Northwest National Laboratory (PNNL). Its acronym is AIRS, which stands for Adding Insulation While Residing. The idea is simple: every time a home or building needs to be resided, we should ensure that it is also getting continuous exterior insulation added. The insulation can be foam, mineral wool, or even wood fiber. Most re-siding companies need to start doing this, and most weatherization programs prefer to drill and fill the walls instead of adding continuous exterior insulation.
 The GreenHome Institute is proud to be a PNNL funding recipient to administer this research project here in Michigan. Before taking on the program, we launched a 1-hour continuing education session on the topic. We are looking at researching this approach on at least nine homes and now have our first project completed to share some initial information.
 

The first thought might be energy efficiency, utility bill savings, and comfort for the owners or tenants of homes that get AIRS. However, additional important benefits of this work are the reduction of wall moisture issues and durability risk reduction. In fact, many siding jobs are not taking this opportunity, leaving in place moisture risks that are reducing the life of the walls and homes due to deficient construction and renovation practices. To illustrate this, you can see the Building Science Advisor (BSA) tool evaluation we did on the previous wall assembly versus the new one here. Here is a CEU webinar we did on the Building Science Advisor tool.

According to the BSA tool, adding 1 inch of Owens Corning EXTRUDED POLYSTYRENE (XPS) continuous exterior insulation to this first test home significantly reduced the risk of wall sheathing moisture content and mold.

 

We suggested that the siding contractors add two inches of insulation, but they were fairly resistant to that idea – which is what this research project is about. Trying to convince siding contractors that adding insulation is important is going to take a lot of work. Adding more insulation requires more effort from the installer.  Design conversations will happen, and they will be different for each home.

 

However, let’s look at the wall’s durability. If we had added the additional one inch as advised in Climate Zone 5, you can see that scenario versus the two inches suggested below, which moves it from a potential sheathing risk to the light green zone of reduced risk. 

From an energy efficiency standpoint, each home we work with receives a GreenHome Inspection before and after work is completed. This process includes reviewing many components of the home. Still, the focus of this program is to give the home and overall US DOE Home Energy Score and determine the home’s air leakage and total energy usage before and after the retrofit. For this particular home, the overall score went from a 4 to a 6, which included over $100 in utility savings and nearly 15 members in total energy reduced both in heating and cooling, which was the result of the exterior rigid being added, three windows being replaced, and a 22% air leakage reduction. If you do the math, that is a 13% savings in energy usage, which gets us pretty close to the savings needed for the Inflation Reduction Act State HOMES rebates of 15% in measured savings needed to get $4-$8k in rebates.   

Not only are energy and money being saved, but the owner also said, “I’ll add that aesthetically, the house looks great. From a functional standpoint, my wife and I definitely have noticed that the two bedrooms that previously felt colder than the rest of the house feel much more comfortable.”

 

The other aspect of our GreenHome Inspection included reviewing ventilation systems. With a tighter home, we need to see if ventilation needs to be improved to optimize occupant health when these jobs are being completed.

 

Stay tuned as we report on the eight additional homes. Note that PNNL will be releasing case studies on these homes. Two GreenHome Institute members have already completed an AIRS study on their homes. One case study is forthcoming, and the other, which you can find here, was done by Tom at Builder World Builders.

Please review part 1 of this series, then continue below

 The remainder of this series will describe what makes LEED a challenge as well as what makes LEED easier on existing homes projects.

 The ENERGY STAR Homes program is an ideal goal for all major renovation projects to strive for, but it can be very difficult to meet if there is no plan or budget to change certain features. Reviewing the ENERGY STAR thermal enclosure checklist, here are the exceptions granted:

1. High-Performance Fenestration not required for existing windows that are not being replaced
2. High-Performance Insulation not required for existing walls that aren’t impacted by the renovation.
3. Slab insulation is strongly encouraged but not required to meet or exceed 2009 IECC levels.
4. Attic insulation at the intersection of existing roof and existing exterior walls does not have to meet R-value requirements.
5. Advanced framing is not required on existing framed walls,
6. For insulated ceilings with attic space above (i.e., non-cathedralized), Grade I insulation extends to the inside face of the exterior wall below and is ≥ R-21 in CZ 1-5; ≥ R-30 in CZ 6-8.
7. Air Barrier is needed except for Existing sill plates on top of concrete are not required to be placed on a foam gasket.

 Review technical details here:

https://basc.pnnl.gov/checklists/energy-star-single-family-new-homes-version-331-revision-11

Insulate and airseal rim band joists

 

Garage pollution protection can be achieved while creating the air barrier

 Place all air-handling equipment and ductwork outside the fire-rated envelope of the garage. Tightly seal shared surfaces between the garage and conditioned spaces, including all of the following:

• In conditioned spaces above the garage, seal all penetrations and all connecting floor and ceiling joist bays.
• In conditioned spaces next to the garage, weather-strip all doors, install carbon monoxide detectors in rooms that share a door with the garage, seal all penetrations, and seal all cracks at the base of the walls.Watch out for CO detectors, too, if they are not near the garage, and the electrician may need to wire one near the garage. You may be able to get an exception for battery backup only if there is no easy way to wire it. Check with your provider at the start of the project.

 Put together an air seal and insulation plan with your contractor and submit it to your LEED Residential Provider to ensure it is sufficient. This is mandatory for all midrise multifamily buildings.

 What do I do with mechanical and HVAC?

 The next biggest barrier to achieving LEED in older homes is an energy-efficient, properly functioning, and commissioned HVAC and mechanical system. This includes proper sizing, proper functions, proper air filtration, and well-sealed ductwork to deliver air.

 One of the biggest HVAC barriers to achieving LEED certification in older homes is ensuring there is no panned ductwork in the floor or wall joists. Ensuring this does not happen improves the Energy Rating Index, or HERS. Any existing home found to have this ductwork panned anywhere on the floors, walls, or attic must be re-ducted. This may require the drywall to be torn out and redone, which can be costly.

 Another option is to use the existing ductwork for a ventilation system, which negates the need to have it fully ducted, though this is still recommended. Then, consider radiant or ductless mini splits for heating and cooling.

 *Note that getting a mini split might not resolve humidity issues either, so there are bonus credits in v4.1 Residential for products like dehumidification or ventilating dehumidifiers. These will reduce the humidity issues that are not resolved by mini splits. Also, existing homes suffer more from humidity issues than new homes.

 If the system must be replaced with a new ducted HVAC system, it must be correctly sized. This is a good way to seal the ductwork; this can be done as the ducts are being rebuilt if they were panned in the joists; some technologies seal existing ductwork from the inside. If the filter box is one inch, you can add a MERV 8 filter or higher (10 for additional points), but the static pressure of the system will need to be checked; otherwise, if getting a new HVAC system, consider adding a 4-inch filter to reduce static pressure and improve system performance. Getting a new HVAC system will also help you get a better energy rating, and many Inflation Reduction Act tax credits apply in the US. Consider a heat pump to get the funding and achieve the best energy rating with lower utility bills in many cases.

 In summary, commissioned, right-sized HVAC systems with reduced duct leakage and good filtration are important. During the LEED preliminary rating, the HVAC contractor can measure the size of the current system and complete the HVAC design report relevant to the planned home energy upgrades to determine if it is oversized using the ENERGY STAR guidance.
Stay tuned for next month’s Part 3 LEED Renovation Durability and Healthy Home Opportunities.

With the end of the year approaching, you may need to accumulate and/or report your year-end continuing education accomplishments. Below, you can just learn how to find, manage, and report any GreenHome Institute CEUs you have accumulated. Then, please find out how to get more CEUs quickly if you need them.

End of the year CEU Reporting

The vast majority of GreenHome Institute’s educational sessions have been approved for the following CEU types:

Green Business Certification Inc. (GBCI) Building Performance Institute (BPI) NonWholeHouse American Institute of Architects – AIA (HSW) Certified Green Professional (NARI & CGP) Certified GreenHome Professional (CGHP) Pillar(s): Energy, Materials, American Institute of Building Designers (AIBD) Building Science Institute (BSI) Verifier Society of American Registered Architects (SARA) Certified Passive House Consultant (CPHC)Some sessions also include LEED AP Homes or BD+C and the MI Realtor license.In addition, many sessions may also qualify for various local, state, and regional programs for builders, designers, real estate, and engineering license renewals.

Each program has various reporting requirements. However, the vast majority of them are self-reporting, which requires logging into your portal to report on each course. AIA and SARA report for members. Maintaining backup documentation for potential audits and accurate reporting is a good idea.

GreenHome Institute tracks your CEUs in two places: live session attendance is tracked in the Gutenberg portal, and on-demand attendance is tracked on Thinkific. All AIA member attendees are also added to the AIA portal as long as the correct AIA # is submitted in the survey following each webinar.

So, for live webinar CEU records, you can log in to Gutenberg Certificates here and create an account if you have not logged in. You need to use the email you used during our live webinars, which will be associated with your certificates. If you used multiple emails, you may have multiple accounts – we can just merge these whenever you’d like. This compiles a database of the sessions you’ve attended; download these to retain them for your records and submit them to your CEU provider.

For on-demand class attendance records, you can log in here, access your certificates, download them, and report them to your CEU provider.

For AIA and SARA CEUs, check your transcripts. If there is a course you have a certificate for from either of the various methods above, email your certificate proof and AIA number to Brett.Little@greenhomeinstitute.or for reporting assistance. Please see below for a potential solution if you still need the certificate.

Rapidly getting CEUs completed to report for the year’s end.

Who doesn’t wait until the end of the year to get their CEUs? We get it. You are busy, and you will cram, or maybe you just need a few more CEUS. We are here to assist you!

Head over to our on-demand education CEU channel here to check out our CEU webinars on demand and watch them on your own time; take the quiz with an 80% passing rate, drop in your CEU provider number (AIA or SARA), and that’s it!

From now until January 1st, 2025, we are offering a 50 percent discount on our on-demand education CEU channel.  Use code “ghice50” for the discount.

Better yet, please help us reach our goal of 400 members by the end of the year. As an active member, you get instant access to all our on-demand education CEU channels for free.

All of our live webinars are free, and the on-demand courses are low-cost. This is in an effort to be equitable and to support education needs and to help ensure widespread access to residential green building education.

There are no live CEU paywalls here, however…

We have to pay for the cost of the CEUs, the technology to provide them, our staff to manage the volunteer speakers and the management of the CEU certificates. Please consider donating to help us continue to do this work and ensure everyone can access residential green building knowledge, awareness, and continuing education.

Click here to donate and help us reach our year-end goal. Better yet, help us reach 400 members by 2025 – support our work and take advantage of many benefits, including all-on-demand CEU webinar access. Check out our membership benefits here. 

There are now three updates on the Inflation Reduction Act: Tax Credits and Homes Rebates.

The first is specific to the rollout of the HOMES rebates in Michigan, the second is related to product manufacturer registration to help ensure Inflation Reduction Act qualifying products are easy to determine, and the last applies to multifamily and commercial extending the 179D rebates to be adjusted for inflation.

 In Michigan, the Department of the Environment, Great Lakes, and Energy (EGLE) has released an update on the rollout of the HOMES rebates. The bottom line is that it seems rebates will only apply to households with incomes at or below 150% of the Area Median Income (AMI), and they will pilot the program first in Holland and the UP. Finally, they are looking to onboard contractors to help deliver the rebates as part of their service offerings. The full program will roll out sometime in early 2025 for the rest of the state. You can stay updated on what is happening and get registered here if you are a contractor. If you are outside of Michiganm, you can find out what your state is up to here.

 If you are above the income limit, you will likely benefit from the Inflation Reduction Act Homes 25C tax credit instead. GHI recently conducted a webinar that discussed this program and how to utilize it in more detail. GHI Education Manager will be on a panel giving another update on this incentive program during the Dec 12th DOE Residential Better Buildings Webinar; you can learn more and register here.

There has been some confusion about what products qualify for the tax credits, and to help clear it up, “manufacturers will be able to use the IRS Energy Credits Online Portal (IRS ECO) to register (their products) with the IRS.” To help with tax consultant confidence, “beginning in 2025, for each item of specified property placed in service, no credit will be allowed unless the item was produced by a qualified manufacturer and the taxpayer includes the PIN for the item on the taxpayer’s tax return.”

 Finally, for multifamily housing project teams, the 179D tax credit was designed to give tax incentives per square foot for more energy-efficient buildings or those renovated to achieve better results. Due to the cost of inflation of improvements to buildings or building more energy-efficient buildings, the IRS has announced increases in the available tax credit amounts. You can learn more about the increase on page 15 here. Note that while GHI has yet to do a 179D tax credit webinar, we did cover it briefly during a 45L tax credit webinar also related to energy-efficient new homes and multifamily buildings.

 In summary, the Inflation Reduction Act funding is one small component to help fund the transformation of our housing sector. Of course, there are going to be new changes and updates to this program, especially in 2025. GHI will keep you updated as we learn more about improving our housing stock.  GHI also tracks additional resources for funding and more on our new Resources page. 

In the past, Leadership in Energy and Environmental Design (LEED) residential certification was difficult to achieve in existing homes because it required a full demolition down to the studs and replacement of HVAC systems. However, this has changed. The new LEED requirements allow the structure to be brought into alignment with today’s energy, health, and materials standards to achieve certification. The program now takes an “if it ain’t broke, don’t fix it” approach. In many cases, the less you do, the more you score in the LEED rating system, except for fixing durability issues and improving energy. Often, 10 out of the 40 points available to achieve certification are achieved just by renovating an existing home. When it comes to existing multifamily buildings, there are even more exceptions. There is also the LEED Operations and Maintenance (O&M) program, which instead focuses on sustainable metrics and outcomes such as carbon, utilities and water usage.

 

Conversely, the GreenStar Homes Certification may still be a more appropriate program for existing housing. Enterprise Green’s Green Communities program is typically best for moderate renovations in multifamily projects involving tax credits, though LEED is also an option.

The ten main tips for doing LEED renovations

• Meet the ENERGY STAR Homes requirements only when planning changes to envelope, mechanicals & appliances
• Energy Rating Index (HERS or other) of 85 or lower
• No ductwork panned in the joists post-renovation
• Shower/tub backer must be moisture-resistant
• Fix any durability and water entry issues
• HVAC systems need to be commissioned and may need to be right-sized and improved
• Existing materials that are re-used/refurbished benefit the project
• Water heaters, furnaces, and fireplaces must be safe from exposure to combustion
• Determine existing water flow rates and landscaping
• Determine the benefits to the project in terms of its existing location

Within this article, the following LEED credits and prerequisites are reviewed:

1. P – IN: Preliminary Rating
2. C – IP: Integrative Process
3. P – EA: Minimum Energy Performance
4. R – EQ: Garage Pollutant Protection
5. C – EA: Annual Energy Use
6. C – EA: Refrigerant Management
7. P – MR: Durability Management
8. P – EQ: Combustion Venting
9. P – MR: Environmentally Preferable Products
10. C – WE: Total Water Use
11. P – EQ: Ventilation
12. P – EQ: Compartmentalization (attached housing only)
13. C – RP: Regional Priority
14. C – LT: Site Selection

 

The first part of any new LEED project, whether new construction or renovation, is to assemble your Integrative Project Team and complete the required preliminary rating. Planning a LEED Residential renovation will include an energy rater, LEED Green Rater, a Residential Provider, and potentially a home inspector and/or professional builder to inspect the building.  Because some professionals carry multiple credentials, these roles could be filled by the same person. These professionals evaluate the home’s condition and determine what will be needed to achieve LEED certification.

You may also include a mechanical contractor to give feedback on new or existing HVAC systems, an architect if you plan a major redesign, and/or a landscape architect if you are planning outdoor plantings or redesign. This is a great practice in general, and engaging these three practitioners, specifically, is also a way to earn the LEED point in this section.

At the very least, minor renovations should include the general contractor and mechanical and energy rater (building science background), and major renovations/additions should include the designer or architect.

In the case of planning a major rehab, the full onsite assessment with a rater may not be necessary because most of the existing structure will be removed and replaced, thus starting with a blank slate. Consider a designer or architect instead.

Upon reviewing the structure and systems, these professionals may determine that a total rehab is required to make the home safe, healthy, energy-efficient, and eligible to qualify for LEED.

 

What version of LEED do I use?

Renovations do not work well under traditional LEED v4 for 1 – 4 unit buildings or townhomes.

Instead, use v4.1 Single Family Homes or v4 Midrise or Lowrise, taking advantage of the v4.1 credit swaps under in the US and Canada. Outside of North America, use v4.1 Multifamily Homes.

For multifamily buildings not planning major upgrades, consider using the LEED Operations and Maintenance (O&M) programs. These programs focus more on performance outcomes such as carbon emissions, water use reduction, and other sustainability metrics rather than mechanical and shell improvements. However, to achieve those outcomes, you may need to make upgrades called for in the LEED Residential rating systems.

 You can watch the full CEU Succeed with LEED Existing Homes webinar below – stay tuned for Part 2 of this written series next month.

November GreenHome and Sustainability Job Opening. 

Follow us on LinkedIn at #GreenHomeJobAlert to get these updates in real-time. 

• Outreach Specialist, Performance System Development of New York, Madison WI 
• Multiple positions, Coalition for Green Capital, New York NY 
• Deputy Director, Brightline Defense, San Francisco CA
• Green Building Certification Project Manager, Earth Advantage, Portland OR
• Energy/Environmental Technology Researcher, Berkeley Lab, Berkeley CA
• Program Associate, Electrification Coalition, remote
• Director – Buildings (Technical), International Living Future Institute, remote
• Project Manager – Environmental Health, Elevate, Chicago IL
• Grant Manager, Green and Healthy Homes Initiative, Baltimore MD
• Energy Consultant – Home Energy Rater (HERS), Stephens and Company Inc., Nantucket MA
• Resilience Program Manager, Miami Dade County, Miami FL
• Program Manager, Denver Regional Council of Governments, Denver CO
• https://www.linkedin.com/jobs/view/4058779860/?refId=gTSIA6RR71iwvGoL1ct
• Grant Writer, Beneficial Electrification League, Arlington VA
• Director – Multifamily Outreach, Enterprise, multiple locations
• Climate Workforce Program Manager, Earth Advantage, Portland OR