Explaining Boulder’s 2024 COBECC Updates

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

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.

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

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.