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.

Image sourced from: https://www.hersindex.com

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.”

Image sourced from: https://www.energystar.gov

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.

Image sourced from: https://basc.pnnl.gov

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.

Air source heat pump

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.

duct leakage testing fan

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.

ERV system

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.

On June 1, 2023, the city of Loveland, CO officially adopted the 2021 IECC and implemented some specific amendments. One of the most significant changes has to do with energy compliance evaluation. In the past, builders were allowed to utilize a prescriptive path to make sure their project was code-compliant. However, the updated Loveland building code has mandated that the performance path must be used for new residential building construction. The amendment states the following:

NEW SINGLE FAMILY HOMES, TWO-FAMILY HOMES, TOWNHOMES, AND APARTMENTS MUST USE THE TOTAL BUILDING PERFORMANCE (R405) OR THE ENERGY RATING INDEX (R406) COMPLIANCE PATH.

Because the prescriptive path has been the “go-to” method for many contractors in the past, this recent change may require a little more attention from contractors and guidance from energy experts like us.

All this code jargon might be little confusing. So before we dive in to the details of Loveland’s new rules, let’s revisit what prescriptive and performance actually mean.

Prescriptive Path Vs. Performance Path

In modern day construction, buildings are required to meet certain energy-based criteria in order to be deemed code-compliant. Most municipalities in Colorado follow the International Energy Conservation Code (IECC). In the 2021 IECC (the most recent iteration at the time of this writing), section R401.2 states that in order to reach energy code compliance, there are multiple paths you can take.

The first one is the prescriptive path. This is the “by the book” method. If you are taking this path, you must meet all of the requirements in R401 through R404 exactly as directed. It’s the stricter method, but has generally been the more popular route in the past. However, now that energy standards are becoming tighter, it is also becoming more difficult and costly to stick to the prescriptive path.

On the other hand, you have the performance path. This is a less rigid pathway that gives builders more freedom in designing the home, as long as it meets minimum 2021 IECC energy standards. For this route, a certified HERS rater must first compile a projected energy rating report for the necessary permits. Then they must conduct code verifications throughout the construction process. And lastly, they need to follow up with final testing and a report when the project is done.

With this method, you are able to take advantage of “trade-offs.” Trade-offs are a concept established in the HERS Rating system. This means that a certain high efficiency component of your home can compensate for another aspect of the home that isn’t as efficient. For instance, if you have a very energy efficient heating and cooling system, you might have some leeway with your window U-factors and heat gain coefficients . If utilized correctly, trade-offs can actually prove to save you money! (Check out our article, Saving Money On Insulation With a HERS Rating/ERI in 2021 IECC )

2021 IECC presents two options for the performance path – The Total Building Performance Option, explained in section R405; or The Energy Rating Index (ERI) Option, described in section R406.

Loveland Building Code

While many jurisdictions allow builders the option to take the prescriptive or performance path, this is actually not the case in Loveland. As stated above, the city of Loveland has implemented an amendment making it mandatory for all new construction projects to use the performance path only.

Contractors are able to utilize the Total Building Performance method or the ERI method. Whichever option you choose to follow, you must make sure to hire a qualified individual to prepare the report and conduct the necessary tests. According to Loveland’s list of amendments, any one of the following credentials is acceptable:

• RESNET Rater or RFI
• BPI Building Analyst or BPI IDL
• Other building performance professional approved the building official

Now that the prescriptive path has been phased out in Loveland, we will likely see a shift in how builders are approaching their projects.

Scott Energy Services

It seems like energy codes and requirements are constantly updating and changing. Sometimes it’s hard to keep up! At Scott Energy Services, we make it our priority to stay current on all municipality-wide building codes, so you don’t have to.

We have RESNET-certified HERS Raters on staff, who are well-versed in the procedures needed to successfully conduct a performance-based energy evaluation on your new build. And we serve a wide area of the state along the Front Range, from Wellington, all the way down to Colorado Springs and everywhere in between, including Loveland!

We hope that you will consider Scott Energy Services for your next building project. To learn more about our services, visit us online or contact us to get a HERS Rating quote.

If you are in the building industry, you are probably no stranger to the 2021 IECC. This is the most recent iteration of the International Energy Conservation Code (at the time of this writing), and it has really tightened up certain construction requirements for newly built homes.

One of its most significant changes has been insulation requirements. In the past versions of the IECC, insulation levels have been more monetarily manageable, but the 2021 version has increased insulation requirements significantly. Most notably a call for R30 in the walls and R60 in the ceilings in Colorado’s climate zone.

If you choose to go “by the book” or take the prescriptive path when building, and adhere completely to IECC 2021 guidelines, your insulation costs are going to go up relative to prior years. However, there is an alternative route…

For the first time, the ERI performance route of the IECC codes is starting to be the more cost-effective option, and performing a HERS Rating could potentially save some serious cash on insulation!

What is HERS Rating?

First, let’s have a quick refresher. HERS, which stands for Home Energy Rating System, is a method used by architects, builders, and energy raters, to determine the overall energy use of a home. The Residential Energy Services Network (RESNET) established the HERS index, the standard that measures a home’s energy efficiency. Note that HERS is the RESnet branded term for Energy Rating Index (ERI), which is the terminology specifically used in the 2021 IECC.

In order to calculate the HERS Score of a building, a certified HERS rater must evaluate all energy-based facets of the home, including insulation, windows, heating/cooling units, etc. The rater then uses specialized software to calculate the score of the home – the lower the score, the better.

Where the HERS Rating system really stands out is that it gives you a level of flexibility through “trade-offs.” In other words, a certain aspect of the home with super high energy efficiency can compensate for another area that isn’t as energy efficient. For example, if the home is utilizing high-efficiency heating, cooling, and water heating methods, the wall and attic insulation could possibly have reduced R-values and still have a similar HERS score. With this trade-off, the overall score of the home can still be IECC-compliant, despite the lower energy efficiency of the insulation. Do you see where this is going?

To learn more about HERS Ratings, check out our 4-part article, The Ultimate HERS Rating Guide: Part 1, Part 2, Part 3 & Part 4.

Image sourced from: https://impresamodular.com

Prescriptive Compliance Vs. Performance Compliance

Section R401.2 of the IECC 2021 states that, in order to reach compliance, there are several options you can take. The first option is the prescriptive path. This is the “by-the-book” method, where the builder must follow the guidelines established in 2021 IECC in sections R401 through R404. This route has generally been more common. However, now that requirements are stricter, it is becoming more difficult and costly to stay within the prescriptive path.

As mentioned above, insulation standards have tightened significantly from 2018 IECC to 2021 IECC. While attic insulation previously had to be at a minimum of R49, it has been raised to R60. Similarly, wall insulation has been raised from R23 to R30 cavity (or R20 cavity + R5 exterior rigid continuous insulation). These new levels are much harder to attain (especially in a standard 2×6 wall) and it drives up insulation costs drastically.

That is where the performance path can really come to the rescue. The performance option is a less rigid route that allows builders to design the home in a fashion they see fit, as long as it meets the 2021 IECC requirements for total energy performance. For this route, design teams have the liberty to employ various combinations of design strategies, and technologies to provide the greatest energy savings for the lowest overall cost.

For Colorado, there are two viable performance options in the 2021 IECC  handbook: The Total Building Performance Option, which is explained in section R405; or The Energy Rating Index (ERI) Option, described in section R406.

The two options are similar. They both require the use of a HERS rater to do pre-reports for a permit, then do all the verification steps during construction, and produce final reports at the end of construction. The main difference is that The Total Building Performance Option produces an IECC Compliance report (further explained in R405), while the ERI Option requires a full ERI report (further explained in R406).

Saving Money with Performance Compliance

There are multiple ways to save money when taking the performance route. We’ve already mentioned it, but let’s just drive it home – doing a HERS rating can save you big bucks on insulation! If you are taking the Total Building Performance route, insulation levels must at least meet 2009 IECC levels. But anything at or above that is acceptable, as long as the home meets the 2021 IECC requirements in total performance.

On the contrary, the ERI method does not technically require an insulation minimum. As long as the home yields an overall score of 55 or less, you can take liberties with the insulation thickness. This provides you with the freedom to plan the most budget-friendly approach to your building project.

Say you do end up going with insulation that meets the 2021 IECC prescriptive standards. Using a HERS rating may give you the flexibility to save money on other components of the home.

Also keep in mind that, whether you are taking the prescriptive or performance path, you will be required to get duct leakage and blower door tests. It just so happens that our HERS service packages include both duct leakage and blower door tests. So when taking the total performance or ERI route, you will be bundling all the necessary energy tests (i.e. duct leakage and blower door) and adding that extra flexibility with trade-off options.

While every job is different and each county’s requirements vary, an analysis with a HERS Rating has the potential to unlock more freedom within your build.

HERS Rating with Scott Energy Services

At Scott Energy Services, a division of Scott Home Services, we are your one-stop shop for all your energy needs. Our energy specialists are well-versed in Colorado energy code, and can advise you on your requirements based on your municipality. We offer all the required onsite testing for a standard HERS rating, from the planning to the finished product.

We know that when it comes to energy codes, there is a lot to take in. So if you have any questions, feel free to call us. One of our energy specialists will be happy to help.

If you are in need of HERS ratings services on your next project, visit us online to learn more, or contact us to book your services now.

In today’s day and age, with expenses and bills around every corner, we’re all looking for ways to cut costs. If you are a homeowner, you know that your monthly bills to keep the house going have been steadily increasing over time. One of our biggest burdens are those costly heating and cooling bills.

One way to save significantly on these energy costs is to make efforts to increase the energy efficiency of your house. This can be done in many ways including upgrading insulation levels, increasing the efficiency of your mechanical systems (i.e your furnace and water heater), or reducing the air leakage in your home.

However, one of the best ways to do this is by updating your windows to meet higher energy-saving standards. This is especially true when your windows are older.

But in a world with seemingly endless window options, what qualifies a window as energy efficient? There are two main parameters that are measured in order to determine a window’s efficiency – U-Factor and Solar Heat Gain Coefficient. Having a better knowledge of these concepts can help you choose the windows that are right for your home.

What are U-Factors (U-Value)?

A U-Factor (also referred to as U-value) is a window’s rate of loss of non-solar heat. Similar to insulation R-Values (which we discussed in a past blog), U-Factors indicate the energy efficiency of a window. The lower the U-Factor, the more energy efficient the window is.

Conversely, windows with high U-Factors are less efficient. This form of measurement was created by the National Fenestration Rating Council (NFRC) as a way to have one, uniform method when determining window, door, and skylight efficiency.

A window’s U-Value can be determined by assessing three aspects of the window – the frame, the glazing (or glass), and the spacer. Each plays a key role in achieving an optimum window seal.

Image sourced from: https://www.nfrc.org

What is the Solar Heat Gain Coefficient?

The U-Factor works in conjunction with the Solar Heat Gain Coefficient (SHGC). The SHGC is the measurement of how much radiant heat, or heat produced by the sun, comes in through a window. Similar to U-Factor, the lower the SHGC, the lower the radiant heat transmitting through the window.

As indicated in the chart below, the EPA recommends different U-Factors and SHGCs depending on the region of the country. These calculations are based on the approximate number of days spent heating and/or cooling per region.

Generally, lower U-Values will be recommended in heating-dominated regions (i.e. colder climates).  In cooling-dominated regions with warmer climates, it is not as imperative to have windows that will keep the heat trapped in the home, however, better U-Values can help keep mechanically cooled temperatures inside the home.

Note that the SHGC has a direct relationship with the U-Value. For instance, in the southern regions (shown in red), the U-Factor can be less than or equal to 0.40, but their SHGC must not exceed 0.25.

Homes in northern regions (shown in blue) have several options that qualify for Energy Star certification. With each option, as the U-Factor increases, so does the Solar Heat Gain Coefficient. This essentially means that the heat gain caused by the sun must compensate for the heat loss from a window with a higher U-Factor. It is the tradeoff between these two measurements that helps to create the overall performance of a window.

Image sourced from: https://harveywindows.com/

The window orientation in the home is also important when considering U-Factors and SHGCs. For instance, in a cold climate, a window facing south should have a high SHGC. On the contrary, in a warm climate, a south-facing window should have a low SHGC.

The geographic features of your property must also be taken into consideration. For example, you may have a large tree creating significant shade on one side of the house. That may mean those particular windows should have a higher SHGC to allow for more solar heat, or a lower U-Factor to increase window insulation.

All of these factors are important to consider when choosing the right windows.

Energy Star Rated Windows

In efforts to promote sustainability and energy efficiency, the United States Environmental Protection Agency (EPA) established the Energy Star program. This program gives certain components of the home Energy Star ratings if these components can meet a number of pre-determined criteria. Windows are a key contributor to energy conservation (or lack thereof), and thus they are one of the components that can receive an Energy Star rating.

Image sourced from: www.aaawindows4less.com

Windows must be manufactured to strict specifications in order to meet an Energy Star rated U-Factor and SHGC combination. They are often double or triple paned. And sometimes the panes are even filled with inert gases, such as argon. Because argon is denser than H2O, it helps to stop air from transmitting through the window, which in turn reduces its U-Value.

Image sourced from: www.premiersecondaryglazing.com

The window frame is built tightly around the glazing to enhance insulation, and a spacer is installed to further decrease heat flow and prevent condensation. Also, most modern window panes are constructed with film-coated, low emissivity (or “low E”) glass. Such materials help to reduce radiant heat and UV ray penetration.

All of these window characteristics cumulatively help to achieve an Energy Star rating and increase your home’s energy efficiency.

Benefits of Energy Efficient Windows

Even though high performance windows might be costly up front, they have the potential to save you a lot of money over time. In fact, according to the US Department of Energy, equipping your home with the proper Energy Star rated windows can save you from 7% – 15% on annual energy bills. Not to mention, the overall climate control and comfort of your home will be elevated as well.

As incentives to strive for sustainability, some regions offer benefits such as tax credits and rebates to those who install Energy Star rated windows. So in addition to saving money on those monthly energy bills, you may even get paid by the government!

Many Colorado regions have established rigid, residential energy codes for new construction projects. Places like Denver and Boulder County require new builds, remodels and additions to meet certain criteria established by the Home Energy Rating System (HERS).

When we conduct our HERS rating services, we are assessing multiple aspects of the home to give it an overall energy score. As you could probably guess, one of the main aspects we observe are windows. Simply put, a better U-Value and SHGC will get you a better HERS rating.

Similarly, we conduct RESchecks to help builders and contractors comply with IECC energy codes. And as we’ve discussed throughout this blog, when it comes energy conservation, it’s all about those U-Factors. Windows with optimal energy performance can help contractors meet IECC guidelines.

We hope that this excerpt has given you a better understanding of U-Factors, SHGCs, and the overall importance of good quality windows.

If you are interested in assessing the energy efficiency of your home, please feel free to reach out about our Scott Home Inspection Energy Services.

One question that we are asked frequently is when and where is a HERS rating required in Colorado? A HERS rating can be an alternative solution to following the building codes when building a Colorado home. We covered many of the benefits of performing a HERS rating in our earlier blog about performance vs prescriptive pathways.

However, that does not necessarily mean that a HERS rating is required or preferred. It is typically just an alternative solution to meeting the requirements. As energy codes are updated and tightened up, they can phase out specific design options on homes that can only be achieved by using trade-offs, which are easier to achieve with a HERS rating.

A HERS rating can be a great option to meet the energy requirements, but in some cases can be overkill. In an effort to substantiate the HERS rating system, however, and give consumers more insight into how good a home’s energy performance will be, some counties and cities in Colorado have required or “incentivized” the HERS rating system.

In this part of HERS rating guide, we will cover where and when a HERS rating is more than just an alternative.

Where is a HERS Rating Required In Colorado? One place. Boulder.

Boulder has always been a community bullish on energy efficiency. They are continually pushing the boundaries and have emerged as a leader in this area. They have become a role model for the state of Colorado and the nation between their SmartRegs program to their goals of reducing carbon emissions by 80% by 2050.

Both the City of Boulder and Boulder County building departments require a HERS rating in most instances, but they differ on their specific requirements. In general, the city has more stringent requirements as listed below.

City Of Boulder HERS Rating Requirements:

The city of Boulder requires a HERS rating on most larger projects. A HERS rating will need to be performed on new construction projects over 500 sqft, additions where the floor area of the addition is over 1000 sqft, or interior remodels where the square footage of the project is greater than 50% of the area of the current home. When a HERS rating is required, it must meet the required HERS Score represented in the below table. These requirements are outlined in the cities code documents.

The city has created its own internal building code called the City of Boulder Energy Conservation Code (COBECC). This code is based on the IECC energy code, but with many additions to make homes even more efficient. This code will be updated in 2020 and will include even smaller building projects and remodel projects that do not add additional square footage. More information can be found about this update here.

The HERS score of a home needs to meet a certain level based on the proposed square footage. The larger the home, the more energy efficient it must be, meaning the HERS score needs to be lower as well. The table below represents the HERS scores needed per square footage. As you can see, all homes built over 5000 sqft need to have a HERS score of 0. This means the home is net zero.

Boulder County HERS Rating Requirements:

The county follows a similar path as the city does. However, they are slightly less stringent as to when a HERS rating actually needs to be done vs following the prescriptive tables. Most dramatically, they raise the square footage caps.

Currently, a HERS rating will need to be performed on new construction projects over 3500 sqft or additions where the floor area of the addition is over 1000 sqft. You can see these requirement changes in the county’s easy to use BuildSmart Checklist.

You have many options in the county to defer to an Energy Smart Assessment over a HERS rating when the project is smaller. This consists of an energy audit being performed prior to construction. But the table also shows that you can use a HERS rating instead, which in some cases, can end up being easier in the long run. Read the full set of building energy requirements here.

These codes are always changing, but this gives a brief overview of what Boulder is looking for. If you have questions on HERS ratings or a Boulder code requirement feel free to contact us.

Denver’s Energy Rating Index system

The City of Denver has overhauled its energy requirement system in the last few years. From switching to IECC 2015 building codes, to requiring blower door testing, to creating many code amendments, the city clearly sees the value in energy efficient building.

While a HERS rating is not required in the City of Denver, it is one of the few places that outlines what they want to see when choosing a HERS rating over the traditional prescriptive pathway. A copy of the code requirements can be found here.

Their residential provision documents state that if you do decide to go with a HERS rating for a new construction home, you will need to meet a HERS score of 55 or less.

If you are building an addition, and it is difficult to isolate what section of the home will need to meet the energy codes and what will not, it may be beneficial to use a HERS rating. In this case, the City of Denver has made it very simple. You will need to have a certified HERS rater model the home before construction to get an initial HERS score. Then the post construction HERS score just needs to beat the initial score showing that there was an efficiency improvement. This should be a very easy way to gain compliance on complex additions.

On top of these 2 simple requirements, the city has also added one incentive to use a HERS rating. When submitting your HERS rating for a permit, they offer a $150 discount to offset the cost of the rating. This will help level the cost playing field between prescriptive and performance and give builders more flexibility on the route they choose to take.

Energy Star Certified Homes

One wild card to throw into the mix is when builders are looking to build an Energy Star Certified home. Energy Star has its own set of requirements that a home must meet in order to obtain the familiar blue seal on your project.

These requirements are slightly more difficult than the standard energy codes, which ensures buyers that they are purchasing an efficient and comfortable home.

One of the requirements of Energy Star is to work with a HERS rater that is trained in the Energy Star program to determine a target HERS score. This number will then need to be met during the planning and construction process.

So even if the county does not require an energy rating, if you are planning on building an Energy Star Certified home, you will be needing one anyway. Our HERS raters are certified with the Energy Star program as well and can help with your HERS rating and planning. Learn more about our HERS rating services here.

On The Horizon

Above are the current HERS Rating Requirements in Colorado. However, things are changing rapidly in this state. As the construction boom roars on, we are continuously hearing more information from building officials about upcoming changes.

HERS ratings have been a nationwide success in many states, aiding builders with complex building codes, and bringing energy efficiency into the marketplace. We predict that the demand for these services will continue to rise, and city building departments will begin to adopt the rating system.

Until then, we hope this article helps. If you are interested in talking to us about your next project please visit our HERS rating service page.

As we talked about in the earlier parts of this HERS rating guide, a HERS rating is a calculated score that quantifies the energy efficiency of a home. When a HERS rating is performed before a home is built, it can be used as a method to comply with energy efficiency code requirements instead of following the standard IECC pathway.

This is commonly referred to as prescriptive vs performance energy compliance. When building a home, using the prescriptive pathway requires following the code requirements line by line for each section of the home. Currently, this is more common but as the codes tighten it is becoming increasingly more difficult to meet every line item in the energy code.

The other option is the performance pathway. This includes using secondary reports such as HERS ratings or RESchecks to validate that a home is energy efficient enough to meet the current code standards.

It is called the performance path because you are measuring the physical energy performance of the building as opposed to following a set of guidelines.

This option gives builders the flexibility to alter sections of the home to be lower than the minimum required energy standards and make up for that deficiency elsewhere. This nets an equally energy efficient home as one built on the prescriptive codes but allows builders and architects to be more creative with their techniques and designs.

The above process is called a Trade-Off, and it is what we will be going through in this article.

Common Trade-Off Scenarios

There are endless scenarios where using a trade-off can help the building process but there are ones that come up frequently. A common trade-off trigger is window efficiency.

Trade-Offs: Window Efficiency

Say you are building a home with very large windows covering an entire wall. This is great to maximize your view, but energy efficient windows of this size that meet the prescriptive path U-value can be very expensive and difficult to find.

Because of this, many builders will opt for slightly less efficient windows and make up for it with a more efficient heating/cooling systems, for example.

You may lose more heat through the less expensive windows but it is now more efficient and less expensive to heat your home. This results in an energy neutral trade-off, and through the HERS model, the performance of the home should remain the same.

Trade-Offs: 2×4 Framed Exterior Walls

Occasionally, a builder or architect will want to use 2x4s to frame the exterior walls instead of the standard 2x6s. This typically cannot be done while following the prescriptive tables because the required exterior wall insulation is more than what can fit in 4 inches of space, or would require the use of more expensive closed-cell spray foam insulation.

However, this can be accomplished with a trade-off. The decrease in exterior wall insulation will cause your HERS score to increase. This can be offset by adding higher efficiency HVAC equipment, adding more insulation in other areas, or adding solar or other power generation techniques.

Rewards For Going Above and Beyond

Aside from trade-offs alone, going further than minimum expectations will decrease your HERS score as well. This means you get rewarded for being a great builder. If you have a duct leakage test performed, and the results are better than what was projected on the original HERS report, the HERS score will decrease.

This gives you extra room to make changes in the future if needed. A buffer zone in case you need to make an unforeseen trade-off. When building on the prescriptive path, you cannot capitalize on areas where you are more energy efficient than what is required.

The Trend Towards Performance

Because of the benefit of trade-offs, consumer understanding, and the demand for EnergySTAR homes, HERS ratings are becoming more and more popular and relevant in the building community.

To gain the maximum benefit from a HERS rating and the trade-off component, it is important to work with an experienced HERS rating company. A professional HERS rater will be able to identify where using trade-offs can save money and building time to ensure your project moves forward smoothly.

If you are interested in our HERS rating services, learn more here. We would be happy to talk to you about your project and answer any questions you may have.

You may have heard the term “HERS rating” used regarding home construction and energy efficiency.  You may have even seen and read through a HERS report, or you may have a HERS certificate for your own home. Or you may have read our first blog in this series, What Is A HERS Rating.  Many have heard the term, but might not fully understand how to decipher the final product: The HERS Score.

To review, HERS is an acronym that stands for Home Energy Rating System. The HERS index, also known as the HERS score, is the industry standard that is used to measure a home’s energy efficiency.

A HERS rating can be used to compare a home’s energy efficiency to another home of similar shape and size.  Because the HERS index compares efficiency on a relatively “apples to apples” basis, the HERS score can be used effectively to compare one home’s efficiency against other similar homes.

So what does the HERS Index look like?

The HERS rating process is well defined for the building community as a solution to meet specific building codes. But as a consumer, the HERS score is the official product of the rating that you can use to compare properties. So, how do you interpret the HERS Score Index?

With a HERS score, the lower the score, the more efficient the home is.  The HERS index uses a scale in which a HERS score of 100 indicates a standard new home score, and a HERS score of 0 indicates a home that uses zero energy.

The HERS Score can be useful when purchasing a home or when building a new home, as it can give you an easy-to-understand expectation of what your energy consumption, energy bills, and overall comfort will look like.

Many counties in Colorado are accepting or requiring a HERS Rating on new construction homes. Are you in need of a HERS rating? Learn more here. 

Here are a few examples of HERS scores, and what they mean:

• A home that scores a HERS  130 is 30% less efficient than a standard new home. You could expect that many existing homes older than 20 years old with minimal upgrades would score in this range.
• A home that scores a HERS 70 is 30% more efficient than a standard new home.  This is a big improvement, but is not as difficult to attain as many might think.  Many newer homes or retrofitted homes with good insulation levels, higher efficiency heating and cooling systems, and higher efficiency lighting will score in this range.
• A home that scores a HERS 50 is 50% more efficient than a standard new home.  This is where we’re really starting to see some extra effort put in toward green building.  This home will typically be designed with energy efficiency in mind, and will have above average insulation levels, high efficiency HVAC systems and water heating, and higher quality windows.
• A home that scores a HERS 0 is 100% more efficient than a standard new home, and is a net-zero energy home.  This is typically only attained when the home has an energy efficient design from top to bottom, along with renewable energy such as Photo-Voltaic solar installed on the home, to produce as much energy as the home uses.

These are rough examples, but many factors go into a HERS rating to determine the end score. An improved HERS score can be attained with numerous combinations of energy efficient measures.

RESNET has created an interactive tool to help consumers and builders understand a HERS score at every level. This breaks down the efficiency/health levels of the home, energy cost savings, and carbon emissions.

What construction changes affect a HERS Score?

A certified HERS rater models a home from top to bottom in HERS software. Each energy design change will slightly change the HERS Score as well. The following are some of the key factors that will affect the final HERS score of a home:

• The area and insulation levels of the thermal envelope, meaning all of the floors, walls, and ceilings of the conditioned space
• The windows, including window area,  orientation, shading, and the insulation quality of the windows
• The heating, cooling, and water heating equipment
• The lighting and standard appliances that will use energy in the home, such as all kitchen appliances and the clothes washer and dryer
• The overall air leakage rate of the home.  High air leakage results in more energy needed to keep the home heated or cooled.  Air leakage is measured on the finished home using a blower door test.

Changing one of the above items can have a range of effects on the outputted HERS Score. This is where an experienced HERS rater can help balance the inputs and help find ways to reach the desired HERS score on any type of property. This can also be used to a builder’s advantage as well by making trade-offs.

A Blower door test is used during the HERS rating process to test the air leakage. This number is factored into the score.

A trade-off is where a builder adds more of one energy efficient item to offset the lack of another. This is not used to bypass the energy codes, but it does help the builder when there are design issues that make energy compliance in certain areas more difficult to achieve. We will talk more about trade-offs in a later part of this guide.

You can see that having an efficiency score to assign to a home can be a very helpful tool.  We will explain in detail in upcoming posts how many municipalities are using the HERS index as the standard for meeting energy efficiency compliance in their building codes.  We will also show how a HERS rating on your home can be useful for resale or for determining the best ways to improve efficiency.