In this day and age, energy efficiency is more important than ever. Building codes have grown stricter with the goal to reduce energy consumption, stimulate sustainability, and increase long-term savings. We needed a way to standardize these code requirements, which is why different energy efficiency ratings have been developed over recent years. But with so many ratings and certifications— like HERS, ENERGY STAR, DOE Zero Energy Ready Home, and the newer ENERGY STAR NextGen— understanding what each one means can get confusing! In this article, we will compare and contrast each of the primary energy ratings systems to help clear things up.

HERS Ratings

This is one of the flagship energy services that we offer at Scott Home Services. Developed by the Residential Energy Services Network (RESNET), the Home Energy Rating System (HERS) is a scoring system that measures the energy efficiency of a home. This is nationally recognized method to meet IECC energy code standards in many municipalities.

During the HERS rating process, the home is assessed based on a list of criteria including:

• Insulation Levels
• HVAC Systems
• Windows and Doors
• Ductwork
• Air leakage (Blower Door Test)
• Water heating
• Solar/renewable energy use (if applicable)

A certified home rater performs a full energy rating on the home by analyzing aspects listed above using a specialized software. The results of the data analysis are compared against a “reference home,” and a resulting HERS score is created.  A lower score means the home is more comfortable and energy-efficient. So the lower the score, the better.

ENERGY STAR

ENERGY STAR is a program implemented by the US Environmental Protection Agency (EPA) as an initiative to “protect the environment, improve air quality, and protect public health.”

In order to be branded with that recognizable blue logo, a home must be evaluated by a certified ENERGY STAR rater. A HERS evaluation is included as part of the qualification process. The home must meet a predetermined HERS score (based on several factors like climate zone, house size, etc.), and also meet strict standards for:

• High- performance insulation, doors and windows
• Efficient HVAC systems and ducts
• Proper air sealing and ventilation
• Energy Star-rated lighting and appliances

DOE Zero Energy Ready Home (DOE ZERH)

DOE ZERH, which was established by the US Department of Energy, is a type of certification that signifies an extremely high performance home. This is meant to build upon the already stringent ENERGY STAR rating.

The difference is that these homes must either have solar installed to meet net zero energy usage, or have solar-ready infrastructure installed to be able to reach net-zero energy usage. Additionally they must have a stricter focus on indoor air quality, utilizing the EPA’s Indoor airPLUS guidelines.

Indoor airPLUS is a program designed to “improve the quality of indoor air by outlining construction practices and product specifications that help minimize exposure to airborne pollutants and contaminants.” Learn more about it here.

With all of these sustainable features in place, the house should have the infrastructure in place to offset most, if not all, of its energy usage with photo-voltaic solar. If the homeowner opts to install the solar needed, the house can achieve net-zero energy usage (or close to it), hence the name of the certification.

ENERGY STAR NextGen

Just when you thought a home couldn’t get any more energy efficient, out rolls the ENERGY STAR NextGen program in 2024. This is the strictest of all the energy efficiency ratings. It incorporates all the standards of the ENERGY STAR, but also emphasizes a focus on electrification, decarbonization, and grid-interactive technologies. Requirements include:

• High-efficiency electric heating and cooling
• Electric water heating
• Wiring for electric vehicle charging
• Induction cooking technology
• High indoor air quality
• Solar readiness
• Smart grid capabilities (for demand-response and time-of-use optimization)

This process can certainly be costly for the homeowner and difficult for the contractors while building . However, the end product can prove to have multiple benefits such as significantly lower energy bills, smaller. carbon footprint, improved indoor air quality, reduced noise, and even increased resale value!

Check out the table below 👇 to see how each of the energy efficiency ratings differs.

Need Energy Services?

Whether you need to meet your local building minimum code requirements, or you are striving for an ENERGY STAR NextGen certification, you’ve come to the right place! Because all 4 of the energy efficiency ratings discussed above are structured on the HERS ratings – a service we offer!

We can help you with virtually every step in the process. We proudly offer a whole list of energy services – including HERS Testing (projected, mid-construction and final), Blower Door Testing, Insulation Inspections, Air Barrier Inspections and Duct Leakage Testing – to help you reach whatever energy goals you may have.

Furthermore, our Energy raters are also ENERGY STAR certified. So if you are striving to meet the ENERGY STAR, DOE ZERH, or ENERGY STAR NextGen qualifications, our specialists can aid in evaluation and verification.

Have Any Questions?  Feel free to give us a call to talk to one of our energy experts.

Want To Learn More? Visit us online to find out more about the services we offer.

Book Your Services Today! If you’re ready to get started, CLICK HERE.

If you are a builder that has worked in the City of Boulder, then you know that Boulder has its own subset of Energy Codes outside of the IECC standards that have been adopted. These codes contain amendments and additions to the standard IECC codes that they believe better serve the city as a whole.

Recently, the City of Boulder announced that effective December 1, 2024, they will implement key updates to the City of Boulder Energy Conservation Code (COBECC). These 2024 COBECC updates will affect the energy code guidelines for new residential buildings, additions, and renovations.

We know that these rules can get pretty complicated. That’s why our energy services team is dedicated to staying on top of the Colorado energy code. Our lead energy specialist, Luke Griess, attended the city’s meetings and compiled the must-know code changes on the horizon.  Let’s dive right in!

All-Electric Homes 

The biggest change to the COBECC this year will be aimed at reducing carbon emissions by moving towards all-electric homes. Under this new code, all new builds are required to have all-electric equipment for heating, cooling, water heating, and appliances. For existing homes, existing gas equipment can remain, be extended, or be replaced with like-kind systems. But any new mechanical systems or appliances must be all-electric.

The most affordable option for electric-based heating and cooling equipment is an air source heat pump system, which has both heating and cooling capabilities.  These systems can be installed as ducted or non-ducted systems, and are becoming increasingly more efficient.  Heat pump water heaters will generally be your best option for water heating.  And to replace gas cooktops, you can go with electric or induction cooktops, which are becoming more and more popular. Induction cooktops utilize electromagnetism to generate heat and are highly efficient.

Lower ERI/HERS Requirements

The previous energy code for the City of Boulder required new homes to meet an ERI (Energy Rating Index, also known as a HERS score) based on the square footage of the home.

This meant that if a smaller home had good insulation, good windows, and energy efficient equipment, it could achieve a satisfactory HERS score without any solar features. Medium-sized homes needed to meet an even lower HERS score, which required moderate photo-voltaic (PV) solar features.  And homes over 3,000 square feet needed to meet a HERS score of 0 (a Net Zero Home). This means that these homes needed a large PV array that was capable of producing as much energy as the home’s critical systems were anticipated to consume on an annual basis.

With the new code, homes or ADUs under 1,000 square feet have the option of simply showing prescriptive compliance, where they meet the code minimums for insulation and windows.  But for homes over 1,000 square feet, the HERS requirement remains. However, the square footage-based targets are more stringent, and there is now a HERS score that you must meet prior to solar.

Under the COBECC 2024, for new construction:

• Homes over 3,000 square feet will need to meet a HERS 0, while also meeting a Pre-Renewable Energy HERS 50
• Homes 2,999 square feet and under will need to meet a HERS 30, while also meeting a Pre-Renewable Energy HERS 50

The pre-solar requirement of 50 (mentioned above) will require that the home is built with high levels of insulation, windows with lower U-values, and better mechanical specs. Additionally, for most every project, this will result in solar being required to meet the Post-Renewable HERS scores. There is also no longer an envelope backstop, where prescriptive insulation levels had to be met, even on HERS projects.

Duct Leakage Testing Requirements

Duct leakage testing is now required for all new ducted systems, regardless of the location of the ducts. In the previous iteration, you could be exempt from duct leakage testing if all the ducts were within the conditioned space.  Now testing will be required for all duct systems inside or outside the conditioned envelope.

Notably, this is standard for all counties in Colorado that have adopted IECC 2021, so Boulder is simply catching up here.

At Scott Home Services, duct leakage testing is one of the primary energy services we offer. We recommend testing at the rough-in phase so that duct leaks can be caught and sealed while the ducts are still exposed.

If you are performing a HERS package with us, this will be included in your initial quote.

Mechanical Ventilation

ERVs/HRVs will now be required to achieve sufficient mechanical ventilation in the home. Mechanical ventilation systems (ERV/HRV, bath fans, kitchen exhaust) must all be tested and verified for proper airflow and efficiency by an approved third party at the completion of the project.  Mechanical ventilation testing is one of the services we provide at Scott Home Services. This can be performed at the same time as your final blower door test – another energy test required by COBECC.

COBECC Requirements for Remodels and Additions

When it comes to remodels or additions to existing homes, the COBECC requirements aren’t changing all that much:

• For level 1 and 2 alterations (minor remodel projects), you will still have the option of going the prescriptive pathway and meeting the code minimums for any new insulation or windows.
• For level 3 alterations (significant remodel projects) and additions over 1,000 square feet, you will have two options. 1) The project will need to use a HERS to meet an ERI/HERS score of 50 or lower.  2) The project needs to show a 30% reduction from the existing building’s ERI/HERS score. If you select the second option, a baseline HERS report would need to be prepared on the existing home. Then a projected HERS report would be prepared on the proposed home that must show a 30% reduction from the original HERS score.

Additionally, there is no longer a separate category for level 4 alterations. These are now considered part of level 3.

Additional Conservation Credits for COBECC Compliance

Finally, there is also a list of Additional Conservation Credits that that each project will have to meet. The different credit options are outlined on table R408.1 of the code (shown below). There are several credits available for using building products with low embodied carbon. Some other credit options are available for energy efficient features, such as geothermal heating/cooling, smart electrical panels, heat pump water heaters with demand response controls, and many more.

• For new homes, a total of 10 credits is required, which must be detailed on the plans and verified at the completion of the project.
• Remodels or additions to existing homes will require 5 credits.

One of the most reasonable methods to attain all of the credits needed for a remodel/addition is to have an Energy Audit performed on the existing building prior to beginning the project. This is another service we offer!

For more info about the 2024 COBECC update, you can visit the City of Boulder’s website OR watch a recent webinar here.

Scott Home Services – Your Guide to Colorado Energy Code

We know that all these code updates can be a lot to digest. And as cities like Boulder continue to move toward increased energy efficiency and sustainability, it’s inevitable that code updates and changes will continue. That’s why we have a team of energy specialists dedicated to staying informed about these types of changes. If you have any questions about the upcoming 2024 COBECC updates (or any CO energy codes for that matter), do not hesitate to reach out to our energy team.

If you are a builder or contractor in need of energy services on your next project, we hope that you will consider Scott Home Services. We have an extensive list of energy services, such as duct leakage testing, mechanical ventilation testing, HERS Rating Services and more!

To see a full list of our energy services, visit us online or you can contact us to book your energy services today.

You may have heard of a duct leakage test in Colorado, and you might be wondering if it is required for your new home. In this article, we’ll discuss the test, when it is required, how it is performed, and what you’ll need to do to pass. Let’s get started.

Understanding When Duct Leakage Testing is Required In Colorado

Duct leakage testing was first required by the 2015 IECC building code. This means that any Colorado counties or cities that have adopted the 2015 IECC (or any subsequent iterations of the code) are required to perform duct leakage testing on all new homes or additions with duct systems. According to the 2015 IECC and 2018 IECC, duct leakage testing is only required on ducts that are located in areas outside of the conditioned space, such as:

• An attic
• An uninsulated crawl space
• A garage
• An exterior utility room
• A garage attic

Essentially, if any piece of the system is outside the heated space, you will need to perform the test. Even if there is just one flex line going through an attic, or an unconditioned crawl.

The 2021 IECC duct leakage testing rules are similar to the 2018 and 2015 IECC, except for one very significant difference.

If you look at the “exceptions” in the R403.3.3 Duct testing section of the 2018 IECC, it states: “a duct air-leakage test shall not be required where the ducts and air handlers are located entirely within the building thermal envelope.”

But if you compare that to the R403.3.5 Duct testing section in the 2021 IECC, the above mentioned “exception” has been removed all together. This means that, under the 2021 IECC building code, all air-handling ductwork will need duct testing, even if it does not run outside the thermal envelope of the home. 

Need a duct leakage test performed? Learn more and schedule one today!

How Is The Test Performed?

Using a special fan, air is pumped through your ducts at a specified pressure of 25 Pascals, equivalent to 0.1 inch w.g. (Water Gauge). All of your registers will be sealed during the test. The sealing is performed with special HVAC tape, but many times HVAC contractors will seal the ducts during construction as well. Learn about the best ways to prep for the test here.

By measuring the fan output and the amount of additional air pressure required to maintain the proper pressure in the ducts, the total amount of leakage in your duct work can be measured. When a duct leakage test is required in Colorado, these are the necessary steps taken.

What Counts As A “Pass?”

To pass the test, your home must meet the following test results. Note that numbers 1 and 2 are required by the 2015, 2018 and 2021 IECCs. Whereas, number 3 is only required by 2021 IECC.

1. Rough-in test – If the air handler has been installed, leakage must be less than or equal to 4 cubic feet per minute, per 100 square feet of conditioned floor area. If the air handler is not installed at the time of the test, leakage must be less than or equal to 3 cubic feet per minute, per 100 square feet of conditioned floor area.
2. Post-construction test – Total duct leakage must be less than or equal to 4 cubic feet per minute, per 100 square feet of conditioned floor area. In addition, building framing cavities cannot be used as ducts or plenums, and any mechanical piping carrying fluids over 105 degrees Fahrenheit, or under 55 degrees Fahrenheit, must have a minimum insulation level of R-3.
3. *Additional Rule for 2021 IECC* Test for ducts within thermal envelope: Where all ducts and air handlers are located entirely within the building thermal envelope, total leakage shall be less than or equal to 8.0 cubic feet per minute, per 100 square feet of conditioned floor area.

If you do not pass, your ducts may need to be reworked, or sealed, to reduce air leakage and ensure compliance with the building code in your jurisdiction. In many cases, installing AeroSeal can help seal the system, if the ducts have difficulty passing the test.

For more info about the 2021 IECC Duct Leakage Testing update, check out this article.

Know The Basics About Duct Leakage Testing – And If It’s Required For Your Home!

A properly-built new home will have no issues passing IECC duct leakage standards. So make sure you know what to expect from your duct leakage test, and prepare accordingly – you’re sure to pass with flying colors. We can help with fast scheduling and experienced technicians when you order a duct leakage test through Scott Home Services.

Blower door testing (or air leakage testing) is an important part of the building process, as it determines the overall air tightness of a building, and helps to identify problematic leaks that may be present. As a result, it has been required for all new construction and additions since the 2015 IECC was released. Most CO municipalities have adopted the 2015 IECC by now. And many have moved on to the 2018 IECC and 2021 IECC.

When comparing the three different IECC iterations, their air leakage rules are fairly similar. However, the 2021 version of the IECC implemented a very important update with regards to attached single family, multi-family and small dwelling units.

Since more and more counties are moving toward the 2021 IECC standard, it’s a good idea to get acquainted with this update. As blower door testing specialists, it’s our job to stay on top of these things. So we decided to release an article, specifically about the air leakage section. Let’s dive in!

2021 IECC Air Leakage Testing Rules

As stated above, most of the of the air leakage testing rules have remained the same since the 2015 IECC. We have touched on these rules in a past blog. So if you need to get to up to speed, check out this article.

To summarize, a blower door test must be performed in any new construction or addition. All the windows, exterior doors, flues, and vents (where applicable) must be closed or sealed off during the test. The test must be conducted at a pressure of 50 Pascals; and the result must not exceed 3.0 air changes per hour (ACH) or 0.28 cubic feet per minute (CFM) in order to pass. These are tests that our energy services team has been performing throughout the CO Front Range for several years now.

So What’s the Update?

If you take a look at section R402.4.1.2, you will see that an exception has been added for air leakage testing. It reads:

Exception: When testing individual dwelling units, an air leakage rate not exceeding 0.30 cubic feet per minute per square foot of the dwelling unit enclosure area, tested in accordance with ANSI/RESNET/ICC 380, ASTM E779 or ASTM E1827 and reported at a pressure of 0.2 inch w.g. (50 Pa), shall be an accepted alternative permitted in all climate zones for:

1. Attached single-family and multiple-family building dwelling units.
2. Buildings or dwelling units that are 1,500 square feet or smaller.

This new update essentially allows you to utilize a different metric for attached single-family and multiple-family units or buildings that are under 1,500 square feet when testing each unit individually.

When conducting this test, the blower door specialist must measure the area of all floors, ceilings, and walls to the exterior of the dwelling to calculate its surface area. This means that walls/ceilings/floors shared with adjoining units do not need to be included in the surface area calculation. Next, they perform the blower door test at a pressure of 50 Pascals. We then take our total CFM reading, and divide it by the square feet of enclosure area. If the resulting number is at 0.30 CFM/sq ft or lower, the structure has passed the test.

What’s The Difference?

The main difference between the two air leakage tests is dimensions used for each respective formula and how the results are calculated.

For the original test:

The CFM/sq ft is calculated at 50 Pascals, then multiplied by 60 to yield the air changes per hour (ACH). Next, the square footage of the dwelling is multiplied by its ceiling height to calculate the volume of the space. Finally, the ACH is divided by the volume. The answer to this equation must equal 5 ACH or less in order to pass.

For the updated test:

The CFM/ sq ft is calculated at 50 Pascals. Then, the surface area of all floors, ceilings, and walls to the exterior are summed up (remember this excludes walls/ceilings/floors shared with other units). Then the CFM/sq ft is divided by the overall surface area of the dwelling. The resulting number must be 0.30 CFM/sq ft or lower in order to pass.

Is This Update a Good Thing?

Yes it is! This update has proven to be quite helpful for smaller dwellings. Most homes have similar components, regardless of size (i.e. doors, windows, ventilation penetrations, etc.). This means that whether the home is 5,000 sq ft or 1,200 sq ft, it will have to same potential areas for air leakage.

So during the traditional blower door test, a smaller home with the same amount of air leakage as a larger home is going to yield a higher ACH. For this reason small units have a difficult time yielding a passing test score. The updated test has made a passing score more attainable for small homes.

Multi-family and attached single dwellings (such as duplexes) especially benefit from this new exception. In the past, these types of buildings have had difficulty passing due to leakage occurring into adjacent apartments.

However, this type of leakage is not actually occurring to the exterior, and thus not actually an energy loss from the building as a whole. So that type of air leakage is not as big of a concern, from an energy stand point. As a result, the the new air leakage test allows the tester to omit these shared surfaces when calculating surface area.

Learn more about how to best prepare your multi-family building for blower door testing. Check out our article: 7 Tips For Multi-Family Blower Door Testing.

Blower Door Testing Services

Let’s face it, energy codes are strict. And as time passes by, they will probably continue to get stricter. That’s why it helps to have energy pros on your side to help you reach compliance each step of the way. At Scott Energy Services, a division of Scott Home Services, blower door testing is one of our flagship services. With a team of highly trained, experienced and professional energy specialists, we are equipped to help meet your project deadlines.

If you need an air leakage test or any other energy services, we encourage you visit us online or contact our energy service team today!

At the time of this writing, most Colorado counties have adopted the 2018 IECC 0r the 2021 IECC. These energy standards have established that a number of field tests are required to validate the energy performance of a home. This includes blower door testing and duct leakage testing – both are important tests for evaluating residential energy efficiency. In this article, we will take a closer look at duct leakage testing in Colorado.

IECC Duct Leakage Requirements

When it comes to duct leakage testing, the 2018 and 2021 IECC rules are very similar, save for one key difference. In the 2018 IECC, Duct leakage testing is not required on any part of the duct system that is located within the thermal envelope of the building. This rule is consistent with the 2015 IECC. On the other hand, according to section 403.3.6 item #3 of the 2021 IECC, now all ducts must be tested – even if they are within the thermal envelope.

For more information about the 2021 IECC duct leakage code updates, check out our article, Duct Leakage Testing Requirements in 2021 IECC Codes

Testing is required to be performed by an independent third party. The code applies to new home construction and remodels/additions in some municipalities. These rules will vary from county to county, based on what IECC version has been adopted. So its always a good idea to check with the local building department to see what is required.

Purpose of Duct Leakage Testing:

• Studies show that a typical duct installation loses up to 20% of the air before getting to the registers. If that air happens to leak outside the building envelope, the overall comfort of a home can be compromised, and high utility bills will likely ensue.
• When air is blowing through ducts outside the conditioned space of the home, this can cause a change in pressure between the heated and unheated areas. This can lead to more air movement between the two areas which will transfer heat/cool air outside of the home.
• Leaks in ducts can pull in air from these unconditioned areas. High pressure in an attic, for example, can push dirty or dusty air into the home through small gaps in the ceiling.
• Within the home itself, unbalanced air flow caused by duct leakage can pressurize or depressurize zones causing rooms to be stuffy or to have temperature variation.

When is the best time to do a duct leakage test?

Duct leakage testing can be done during various stages of construction and still meet the specifications of the energy code, although we recommend performing it at rough-in when access is easiest. This also gives you the ability to seal sections of the ducts while they are still exposed.

How do we perform the test?

We use the “Duct Blaster” to test the air supply and quantify leakage. We seal off all the registers in the home and run a fan at a return, or at the air handler to depressurize the system. The total amount of leakage in the system is determined by pressurizing or depressurizing the system with the Duct Blaster to 25 pascals.

Click here to view a great article about duct leakage tests from the air leakage pioneers, The Energy Conservatory.

What Comprises a Pass or a Fail?

The threshold for passing the test is determined by a certain number of CFM of leakage per 100 square foot of conditioned space that the system serves. Here are the baseline numbers given in the IECC 2015 codes.

• 3 CFM per 100 SF – Rough-in—with no air handler installed
• 4 CFM per 100 SF – Rough-in—with the air handler installed
• 3 CFM per 100 SF – Post-construction—with no air handler installed
• 4 CFM per 100 Sf – Post-construction—with the air handler installed
• 8 CFM per 100 Sf – Post-construction—with the air handler installed and all ducts within the conditioned envelope (2021 IECC)

Helpful hints to pass your Duct Leakage Test:

• If this is your first test, always have it performed at the rough-in stage so that issues can be easily addressed.
• Liquid Mastic or “pookie” has shown the best results based on our experience.
• Seal every joint. The test is very sensitive, so the HVAC professional may need to seal quite a bit more than normal.
• The furnace or air handler is often overlooked. Seal around the edges and around the back side of the handler where the returns connect.
• Flex duct is popular in attics. However, the zip ties conjoining them to the system have a tendency to leak. Add mastic to these joints as well to create a tight seal.
• Make sure the filter cover is fully installed and sealed before the test.
• Do a once over of the full system before the test to identify weak or unfinished areas.
• It can be helpful for the HVAC installer to be present during the inspection to help identify and repair leaks on the spot.

Scott Home Services

At Scott Energy Services, a division of Scott Home Services, we have a team of highly trained energy efficiency and air leakage specialists. We offer an extensive list energy services including Duct Leakage Testing, Blower Door Testing, HERS Ratings and more! So whatever your building requirements may be, we are here to be of service.

For more information or to schedule a duct leakage test with Team Scott, click here.

If you are in the building industry, you are no doubt familiar with the International Energy Conservation Code (IECC).  This code is used as an industry standard for new building projects and renovations. And it establishes what guidelines need to be followed in order to meet code. As an Energy Services company, we make it our business to stay in-the-know about any IECC updates or changes. That is why we are going discuss the recent changes to duct leakage testing requirements within the IECC 2021 version.

But before we dive into the IECC changes, let’s first discuss duct leakage testing and what it is…

What is Duct Leakage Testing?

Simply put, the purpose of duct testing is to evaluate how well a home’s duct system can hold air. The more leaks your duct system has, the less efficient it will be.

A leaky duct system will result in wasted energy and wasted money. Furthermore, poorly sealed air ducts can cause unevenly distributed heat or AC throughout the home, resulting in an uncomfortable living environment.

At Scott Energy Services, duct leakage testing is one of our primary energy services. Most counties in Colorado adhere to the IECC standards, and thus, the duct leakage protocol. As a result, we have performed hundreds of these tests with our tried and true method!

How Does It Work?

To begin, all duct openings (including supply and return registers) must be sealed off with specialized HVAC tape. A large fan is then sealed securely to the air handler opening or a large return opening (as shown above). However, this is usually done at rough-in on new construction homes.

We run the fan to depressurize the duct system down to -25 pascals. The amount of air moving through the fan is then calculated. This number, referred to as the CFM25, indicates the amount of air leakage in the duct system.

For more details about our duct leakage testing process, you can check out our website.

How Did the IECC 2021 Codes Change Duct Leakage Testing?

Believe it or not, just one sentence was removed from the 2021 IECC duct testing section. However, this one change makes a BIG difference.

If you look at the “exceptions” in the R403.3.3 Duct testing section of the 2018 IECC, it states that “a duct air-leakage test shall not be required where the ducts and air handlers are located entirely within the building thermal envelope.” This is consistent in IECC 2015 codes as well.

The reason this initial exception existed was because if duct leakage occurred within the thermal envelope, heated or cooled air could still be captured to a certain degree.

Now compare that to section R403.3.5 Duct testing in the 2021 IECC, and that statement has been removed. This means that, in jurisdictions that have adopted the 2021 IECC, all air-handling ductwork will need duct testing, even if it does not run outside the thermal envelope of the home. For homes with more than one HVAC system, both systems will need to be tested.

This is big news, and it might be a bit of a curveball for some builders. This is because it has never been a requirement, since the IECC’s inception of the duct testing rule in 2015.

When comparing ductwork that remains within the thermal envelope to ductwork that exits the thermal envelope, leakage requirements differ slightly. According to section R403.3.6, leakage for duct systems that leave the envelope of the home, must not exceed 4.0. cubic feet per minute per 100 square feet of the conditioned floor area. On the contrary, ducts that remain within the thermal envelope must be less than or equal to 8.0 cubic feet per minute per 100 square feet. So there is slight bit more leniency when it comes to ducts within the thermal envelope.

Builders who haven’t needed this type of testing in past projects now must factor it in. They must be sure not to skip over this stage of testing during their projects. It will also contribute to a marginal increase in costs that must be factored where necessary.

What Are the Benefits Of This Change?

This updated code might ruffle some feathers. But from an energy efficiency standpoint, this rule does have its benefits. One of our certified HERS raters, Joe Ophoff, spoke on the matter:

“In new construction home design, there is a great emphasis on air leakage and distribution.  New homes are designed for super performance, so really fine-tuning distribution systems are necessary for comfort throughout the house. Too much duct leakage can indicate a failure in the installation of the duct system, so we can catch a bad install at the ‘rough mechanical’ phase to ensure things are installed correctly. But also, the duct designs are carefully calculated to ensure distribution equilaterally throughout the house, so any significant leakage would affect that.”

Joe illustrates this point well – it all comes down to energy efficiency and optimum HVAC performance. If your interior ducts have too much leakage, they might not evenly distribute heat/air throughout the house. So when you get the system tested during the building process, you are able to pinpoint any issues and have them addressed before the project is finished.

In many counties across the country, including most in Colorado, Manual J/S/D reports are required to get a permit. These reports design the duct system prior to installation; and they calculate the perfect amount and balance of airflow and velocity for each room of the home. However, these reports assume the presence of well-sealed ducts for the results to match the initial calculation.

So this is another step in the process of engineering a super comfortable home for the homeowner, and ensuring everyone is getting the most out of the energy they are using. We wouldn’t be surprised to see actual airflow balancing or velocity testing requirements in the future to even further verify the performance of the duct systems.

In Need of Energy Services?

At Scott Energy Services, a division of Scott Home Services, we are seasoned duct leakage experts. But that’s not all. We also have a number of other energy services, including energy audits, HERS rating, blower door testing, REScheck report services, insulation inspections and air barrier inspections. And we make sure to stay up on the ever-changing codes, in order to help you move along through your project without a hitch.

But what’s a good duct system without the right mechanical design? As you likely know, the IECC requires all new builds and additions to submit a Manual J, S, and D report to ensure mechanical design code compliance. This is another service that we proudly offer. If you need a Manual J/S/D report, we a have team of experts ready to help!

No matter what your next building project needs may be, we would love to be of service! Visit us online to learn more or contact us to book your services today.

When the 2015 International Energy Conservation Code (IECC) went into effect, blower door testing became a requirement on all new residential builds and remodels. Prior to this code update, blower door testing had been in use for many years. However, this was the first time that it had become mandatory for many new construction projects.

The International Code Council (ICC) saw it fit to address the issues that can occur with too much air leakage in homes. Therefore, this rule was established as a way to increase energy efficiency in new residential builds.

Counties that have adopted the 2015 IECC (or any later edition) require that any new build must have a blower door test performed by a licensed, third-party company. The results of the test must not exceed the region’s maximum leakage rate in order for the building to be deemed IECC-compliant. It is a crucial aspect of the modern building process in the majority of the nation. So what is blower door testing?

What is blower door testing?

A blower door test is a procedure that involves using specialized equipment to measure the exact air tightness of a home. Depending on the region of the country, a maximum air leakage rate is defined, and each new home must meet this air tightness level.

This technique is the industry standard and is extremely accurate. Furthermore, it not only helps to determine the level of air leakage, it can actually help you to determine the exact sources causing the air leaks.

How does it work?

A blower door consists of a frame and flexible panel that fit into an exterior doorway. A powerful, variable-speed fan mounts into the frame.

All exterior openings – such as doors, windows, flues vents etc. – are closed off or sealed. The fan is then activated to blow air out of the house, lowering the inside air pressure. The higher outside air pressure then flows in through any unsealed cracks or openings.

As the fan runs, an integrated pressure gauge measures the pressure differences between the inside and outside of the home, and an airflow manometer and hoses are utilized for measuring airflow.

The equipment used in the blower door test determines a home’s air infiltration rate, which is measured in air changes per hour (ACH). This is the number that is required by the IECC code. For most Colorado municipalities, the air leakage rate for new residential builds or remodels must not exceed 3.0 ACH.

As the blower door fan runs, the technician is able to walk the house, searching for sources of large leaks. Having conducted thousands of tests, our experts know where to look for primary problem areas. Furthermore, we utilize infrared scanning devices to help detect temperature differentials within the home –  a sign that could indicate air leakage.

A specialist can then help to pinpoint the issues, when present, and relay this info to the project contractor in a timely manner. Find out more about common leaks found during a blower door test here.

Do you need a blower door test performed on your project fast? We can help! Visit our blower door service page to learn more and schedule now.

When do you perform a blower door test?

According to the IECC, the test should “be performed any time after creation of all penetrations of the building envelope have been sealed.” Basically, the home should be as close to being complete as possible, with exterior penetrations sealed properly and all the drywall completely installed, before carrying out the a blower door test.

Any leaks caused by an incomplete building envelope could potentially affect the test results. That’s why the full building envelope needs to be sealed before an accurate test can be conducted.

Who can do the testing?

Here at Scott Energy Services, a division of Scott Home Services, LLC, we proudly offer blower door testing services to the Colorado Front Range. We also offer an extensive list of other energy services including duct leakage testing, insulation inspections, air barrier inspections, full energy audits, Manual J,S &D report preparation, as well as full energy rating services including RES-Check reports and HERS ratings. Check out a full list of our services here.

Is this required in the county you are building in?

Most of the counties along the Front Range of Colorado have moved to at least the 2015 IECC building code by this time. However, we encourage you contact your municipality in order to confirm which code guidelines your building project must adhere to.

If you are a contractor, builder or architect in Larimer County, CO, you are probably aware that the area has adopted the 2021 International Residential Code (IRC). This is a series of rules established by the International Code Council (ICC) to which all new residential building projects must adhere.

As of March 2022, several amendments were added to the overall IRC. And Larimer County has opted to adopt these amendments, as well. One of the big changes is that air barrier inspections are now required on new builds.

Building Envelope Performance Verification

The state of Colorado is constantly striving to increase statewide sustainability. That is why factoring in energy efficiency is a major part of the CO residential building process. It is no surprise then that many counties, including the Larimer County, have adopted the energy-related guidelines of the IRC. Chapter 11 of the IRC focuses on energy efficiency.

One of the primary amendments to this chapter now requires “building envelope performance verification.” This means that, before siding is added to a home, a certified inspector must examine and approve its exterior air barrier. Additionally, an air leakage test must be conducted on the home upon completion to make sure it meets energy efficiency requirements. The excerpt below highlights the key points in the amendment:

1. A review of the construction documents and other supporting data shall be conducted to assess compliance with the requirements in this section.

2. Inspection of continuous air barrier components and assemblies shall be conducted during construction while the air barrier is still accessible for inspection and repair to verify compliance with the requirements of this section and Table N1102.4.1.1.

3. An air barrier and air sealing inspection report shall be provided for inspections completed by the approved air leakage testing agency. The air barrier and air sealing inspection report shall be provided to the building owner or owner’s authorized agent and the code official at the time of the framing or insulation inspection. The report shall identify deficiencies found during the review of the construction documents and inspection and details of corrective measures taken.

As stated in the excerpt above, the construction docs will be reviewed by a qualified inspector. These building plans should meet the guidelines established in  the amended rules. Furthermore, the actual construction should follow the construction plans.

It is key to conduct the exterior inspection while the barrier can still be accessed. That way, if any deficiencies are noted, they can be adjusted or repaired efficiently. It would be a much more difficult task to make any air barrier changes after the exterior siding is installed!

A guide in the IRC (labeled as Table N1102.4.1.1) provides an in-depth breakdown of all components of the home, and how each of them should be configured in order to meet code requirements.

Meeting Air Barrier Code Requirements

When it comes to this code, the overall concept is simple – a continuous thermal envelope. or air barrier must be constructed around the house. Any breaks or joints in the air barrier material must be sealed by a code-approved material. Also, the insulation material used for the air barrier cannot be air permeable.

As mentioned above,  Table N1102.4.1.1 provides an extensive explanation regarding each component of the house. So if you want the nitty gritty details, go take a look a the table. But for the sake of this article, we will give you a brief overview:

• Ceilings/Attics – Inspectors will want any access points to unconditioned attics to be sealed with the proper air barrier materials. Additionally, any dropped ceilings or soffits should be outfitted with an air barrier that is aligned with the insulation.
• Walls – Any junctions from sill plate to foundation or top plate to exterior walls must be properly sealed. Additionally, if your attic has knee walls, they must be sealed.
• Windows/Skylights/Doors – All the framing of these penetrations needs to be properly sealed.
• Rim Joists – Exterior air barriers must extend over any rim joists.
• Floors – Any exposed edges of floor insulation must be reinforced by an air barrier. This also applies to cantilevered floors and floors above garages.
• Basements/Crawl Spaces/Slab Foundations – Exposed earth in unvented crawl spaces must be covered with the proper air or vapor barrier. Penetrations in foundation walls and slabs need to be sealed properly.
• Shafts/Penetrations – Ducts, shafts, or penetrations to the exterior or unconditioned spaces must be sealed with approved materials.
• Narrow Cavities – Any cavities too narrow to hold insulation need to be air sealed.
• Garage – Air sealing is needed between the garage and conditioned spaces.
• Recessed Lighting – Lighting fixtures present within the thermal envelope of the building must be properly air sealed.
• Wiring/Plumbing/Other Obstructions – Any breaks in the thermal envelope caused by wiring, plumbing etc. need to be sealed.
• Showers/Tubs – The air barrier installed adjacent to tubs or showers must separate the exterior wall from the tub/shower.
• Electrical or Phone Boxes – Air barriers must be installed under exterior electrical or phone boxes. Air sealed boxes can also be installed as an alternative.
• HVAC Register Boots – HVAC supply/return register boots that penetrate the thermal envelope need to be air sealed.
• Concealed Sprinklers – Concealed fire sprinklers must be sealed, where necessary, according to manufacturer’s recommended method.

Air Barrier Inspections

At Scott Home Inspection, we offer all the Energy Services you’ll need to make sure your building project is up to code. As a qualified third party inspection firm in Larimer County, we have a team of specialists that can inspect and document the exterior of the house to ensure that the building envelope is sufficiently configured.

Additionally, we are also certified to perform blower door, air leakage testing in Larimer County. Due to its adoption of the IECC Residential Energy Codes, Larimer County has required this type of testing in new builds for several years.

By conducting blower door tests, our energy specialists are able to not only determine the energy efficiency of the home, but also identify the sources of air leakage. That way you can make the necessary repairs, as needed, and continue to progress through your building process without a hitch.

We are proud to offer a whole list of specialized Energy Services to Larimer County. We have been providing the region with some of our milestone services such as blower door tests, insulation inspection, and duct leakage testing for years. And now we are ready to take on the newly mandated air barrier inspections with the same professionalism, expertise and efficiency.

If you are in need of an air barrier inspection (or any inspection service for that matter) for your building project, please don’t hesitate to reach out to Scott Home Inspection today! Click here for more info, or click here to schedule your service.

As modern day homeowners, we face so many month-to-month expenses. There are routine maintenance expenses, repairs, utility bills, insurance, mortgage payments and the list goes on. With all these recurring expenses hanging over our heads, there is one thing we all have in common – we want to save money. So how do we do that?

You can, of course, cancel that gym membership, discontinue that Hulu subscription, decrease your daily visits to Starbucks, etc. But how many of us focus on the energy efficiency of our own homes? Air leakage in the home can be a prime source of wasteful energy use and high energy bills.

A bit more knowledge about this topic can go quite a long way. In addition to saving money, decreasing air leakage can also make your living space a much more comfortable and healthy environment.

What Is Air Leakage?

Air leakage occurs when outside air enters the home and conditioned air exits the home in an uncontrollable manner through cracks and openings. When air leakage occurs in excess, it can drastically affect energy efficiency. Furthermore, with air freely transmitting in and out of the home, occupants will have a harder time creating an optimum living space.

Over the years, building methods have advanced to really improve energy efficiency. Various insulation products, house wraps, and building techniques have helped to increase the overall “air tightness” of new builds. It is always recommended to address air leakage throughout the building process, so as to avoid energy efficiency issues down the road.

It is definitely more common for old homes to be drafty, because they were purposely built to have more breathability. But even newer builds can have air leakage issues.

There are a number of common points where air leakage can take place in the home. Windows, doors, recessed lighting fixtures, exterior wall penetrations, ducts, fireplace walls are a few examples of trouble areas (see more examples in the image below).

Some of these trouble areas can be discovered simply through visual inspection. For instance, if you see a large gap between your front door and door frame, there are obviously air leakage issues at that location. And you will want to remedy the defect with the appropriate weather stripping.

However, some of these problematic areas are not so easy to identify with the naked eye. In these cases, you should hire a specialist who can evaluate your home’s energy efficiency with a blower door test.

The Pros and Cons of Low Air Leakage

As we’ve already discussed, reducing air leakage in your home will save you money. During the hot months of the year, a home with bad air leakage means hot air coming into the home, and cool, conditioned air leaving the home.

In this scenario, your AC system will work hard to maintain your ideal temperature, resulting in unnecessarily high electricity bills. And the same (vice versa) thing will happen during cold months – cold air gets in, heated air escapes. This results in a cycle of  year-round energy inefficiency.

On the contrary, an air tight home would improve energy efficiency and help you to save your hard earned cash!

Low air leakage also means a more comfortable, climate-controlled and healthy in-home environment. You will have less fluctuations in your indoor temperature. So when it comes to your thermostat, you can set it and forget it.

Air leakage can allow humid and moist air to enter the home. This can obviously result in an uncomfortable living environment.

But in even worse case scenarios, excessive moisture in the home can lead to chronic mold issues, which can affect occupant health. And if the moisture intrusion is consistent and severe enough, it can lead to interior damage, which may necessitate costly repairs.

The main con of an airtight home is that it creates a potential decrease in overall natural ventilation. Without a natural source of ventilation, airborne particles such as dust, mold spores, germs, and even exhaled carbon dioxide may remain trapped inside the home, creating poor quality air.

This a legitimate concern. We, of course, want to optimize our energy efficiency. But we also don’t want to compromise our access to fresh, healthy air.

Well, this issue has been appropriately addressed by a simple concept: “Build Tight, Ventilate Right.”

When it comes to airtight homes, proper ventilation is key. And two main types of systems are utilized to achieve proper ventilation – Heat Recovery Ventilators (HRV) and Energy Recovery Ventilators (ERV). These systems create a cyclical exchange within the house, which pulls in fresh air from the outside, while expelling stale air to the exterior.

How Do I Know If My Home Has Air Leakage?

Your house likely has air leakage, because pretty much all homes have some degree of air leakage. The real question is how much air leakage does your house have? As we mentioned briefly above, the industry standard for measuring air leakage is a blower door test.

During these tests, a specialized device (shown below) creates a suction to depressurize the home. This depressurized environment allows the blower door technician to measure how much air leakage is occurring in the home, and whether or not further action is needed.

If you are a homeowner in Colorado, we offer a blower door test with our comprehensive Energy Audit. Our energy specialists will evaluate air leakage, but also analyze insulation levels, windows and doors, mechanical devices, and more. An energy audit gives you a full picture of possible upgrades to lower your energy bills.

Most Colorado counties are now requiring newly constructed homes to meet a number of energy efficiency criteria established under the International Energy Conservation Code (IECC). This code’s primary goal is to increase sustainability and to regulate energy consumption.

The code makes blower door testing a mandatory step for many construction projects to ensure optimum energy efficiency. Depending on where you live, the rules of the IECC may even apply to you.

But regardless of rules and regulations, assessing the air leakage of your own home is never a bad idea. Because who doesn’t want to optimize their living space and save some cash while doing so?

If you are curious about the energy efficiency of your home or construction project, feel free to reach out and schedule a blower door test today.