Ask the Expert: Duct Leakage Testing

Question:  What’s the deal with duct testing under the IECC 2009 code?  How can I make sure I pass the inspection?       -Drew, Exeter NH

Many studies have shown that visual inspection of duct seals in residences is not enough. Code now requires a pressure test. Pressure testing ducts as required by the 2009 IECC is far superior to visual inspection and will definitively confirm that duct leakage is kept to a low level. Building Energy Codes Program experts estimate that pressure testing ducts in new residential construction will reduce energy consumption in new homes by up to 10% on average and potentially much more in some homes.

Requirements

Section 403.2.2 of the 2009 IECC states that the sealing of ducts must be verified by a duct pressure test. This test involves using a fan to force air into the duct system and measuring how much air leaks out through cracks and holes (the registers are taped closed for the test). A duct pressure test is not required if the air handler and all ducts are located inside the building thermal envelope. The requirements for how to seal ducts are given in Section M1601.3 of the International Residential Code, and apply regardless of the location of the ducts.

The code allows considerable flexibility in the required test. It can be conducted by anyone, including the installer or a third party. It can be done either after rough-in of the ducts or at the completion of construction (i.e., after drywall has been installed and finished). There are separate requirements for testing at rough-in, depending on whether the air handler has been installed at the time of the test. The post-construction test can measure either the “total leakage” of the ducts or the “leakage to outdoors” (the fraction of the total that leaks outside the conditioned space).

The allowable leakage rates are expressed in terms of airflow (cubic feet per minute or CFM) per 100 ft² of conditioned floor area, when duct registers or boots are taped/sealed and the duct system is pressurized to 25 Pascals (0.1 inches w.c.). Maximum leakage rates for the various testing options are as follows:

Testing Option	Maximum CFM per 100 ft² @25 Pascals
At rough-in, air handler not installed	4
At rough-in, air handler installed	6
Post-construction, leakage to outdoors	8
Post-construction, total leakage	12

The drawbacks of rough-in testing include less accuracy as leaks in the boot assembly cannot be fully measured because drywall is not yet installed. Also, it is only possible to measure total leakage whereas leakage specifically to the outdoors can be measured when the house is completed.

Source: “Duct Testing in New Residential Construction – Code Notes”, Building Energy Codes Resource Center, Article 1694, published August 2009. http://resourcecenter.pnl.gov/cocoon/morf/ResourceCenter/article/1694

Some Tips to Ensure Compliance

It is often helpful to imagine that instead of filling the duct system with air, you are filling it with water – and you absolutely don’t want any water to leak out of the system anywhere.  Ideally, the same care you would use to seal the ductwork to be water-tight should be used when you are sealing the system to pass an air pressure test.

Some other useful tips:

• Make sure that all supply and return ductwork is tightly sealed with mastic or foil tape, not duct tape.  This includes all the seams and anywhere a connection is made.

• Make sure the seams around the air handler unit itself are sealed tightly with foil tape.  Also, ensure that the filter slot is gasketed and seals tightly upon closure.

• Use dedicated ductwork for all supply and return lines; i.e. do not use building frame such as wall-stud cavities or floor joist cavities as ductwork.

• Seal all duct boots that penetrate the sub floor to the sub floor with mastic or foil tape.

• If flex-duct is used, ensure that it is not kinked or compressed.

More information:

For information on efficient duct systems see the ENERGY STAR® write up: www.energystar.gov/ia/new_homes/features/DuctSystems_062906.pdf

For more information on energy efficiency programs in New Hampshire: http://www.nheconomy.com/business-services/energy-efficiency-programs.aspx

“Ask the Expert” Column Coming Soon: Ask Us Your NH Energy Code Questions!

Have a question about the NH Energy Code?  We at the NH Energy Code Challenge would like to introduce our new “Ask the Expert” column, which will be featured periodically here on the blog.

 Write in to us with your questions about the code – the requirements, code compliant building techniques, new products and anything else that you’ve wondered about but never asked.  Bruce Bennett, presenter at our live NH Energy Code workshops and energy efficiency pro, will lend his expert insights into your biggest code issues and questions.

 

About the Expert

Bruce Bennett is a Project Manager with GDS Associates and specializes in the energy efficiency of residential buildings. Bruce is a RESNET-accredited and certified home energy rating provider (HERS) under the Mortgage Industry National Home Energy Rating Standards. Bruce has conducted hundreds of home energy ratings for candidate-homes for the EPA’s ENERGY STAR Homes labeling program, the tax credits through Energy Policy Act of 2005 (EPACT 2005) and for energy efficient mortgages.

 As a project manager, Bruce oversees a staff of 7 residential energy efficiency specialists and home energy raters. Bruce’s team currently supports the implementation of various utility-sponsored residential energy efficiency programs which includes Public Service of New Hampshire, Unitil Corporation, NH Electric Cooperative, National Grid, NSTAR, Northeast Utilities and the Cape Light Compact. Bruce has over seven years of experience working with the REM/Rate software. Prior to the development of the implementation of ENERGY STAR Homes Program and the EPACT 2005, Bruce used the REM/Rate software to model homes for energy consumption and to estimate component-specific energy savings using the software’s energy improvement analysis capabilities.

 Bruce joined GDS Associates in December 2000 and is based in the firm’s New Hampshire office. Prior to joining GDS, Bruce served as a Development Officer with New Hampshire Housing Finance Authority where he provided finance underwriting, loan disbursements and construction oversight for the completion of multi-family housing development projects. He received a Bachelor of Science degree in Environmental Design and a Master of Regional Planning; both from the University of Massachusetts at Amherst.

NH Energy Code Workshop Resources – Available Online!

Did you miss the last NH Energy Code workshop in your area?  If so, we have some good news for you!  You can find much of the content from recent workshops on our website, www.nhenergycode.com.   All PowerPoint presentations and printed workshop packets from both the Commercial and Residential workshops are available here.

We are also pleased to introduce a collection of training videos adapted from the live lectures, posted on this page.  Here you can find topic-specific training modules covering energy issues from air sealing to new energy efficient products.  Each module is just a few minutes long, so pick a topic (or three) and start learning about the NH Energy Code and energy efficient building practices today!  We are continually adding more content to these pages, so check them out often.

As always, if you have any questions or comments please email us at info@nhenergycode.com!

NH Energy Code Challenge Hosts First Ever In-Field Training Session

After listening to much feedback from past workshop attendees, this October, the NH Energy Code Challenge unveiled its first ever “in-field” energy code training session.  This program was specifically designed for a small group of builders and code inspectors to see the code in action in a real residential property under construction. 

Presenter Bruce Bennett points out code-compliant insulation techniques.

Thirteen active participants joined our presenters, Jon Osgood of the New Hampshire Public Utilities Commission and Bruce Bennett of GDS Associates, for a full day of live, hands-on learning.  The day began with coffee, donuts, and an abbreviated classroom session which covered foundational topics from energy code history in NH, to how to demonstrate code compliance and basic building science concepts.

PSA highlights advantages of building to New Hampshire’s Energy Code

Next time you are listening to the radio, keep your ears open for our new public service announcement, highlighting the consumer advantages of building to the new NH energy code standards. Released in mid-June, the NH Energy Code Challenge PSA can be heard on several different radio stations across the state of New Hampshire. If you can’t wait to hear all the great advantages of the new building energy code or if you’re not much of a radio listener then click here to check it out now! Want to learn more? Check out our website, where you can find more information about energy codes, handy checklists and tools, and sign up for live training sessions. Enjoy!

What is the Energy Code, and Why is it Important?

For our first blog posting, we thought we would keep it simple and explore the topic, “What is the Energy Code, and why is it important?”

The New Hampshire Energy Code, also known as the International Energy Conservation Code 2009, is our state’s attempt to curb some of the energy used in new residential and commercial buildings, because frankly, they are energy hogs! In the U.S. the residential and commercial building sectors combined use 39% of our total energy, two-thirds of our electricity, and one-eighth of our water. Buildings also use more energy and emit more carbon dioxide then either the industrial or transportation sectors.

In 2009 the NH Building Code Review Board, made up of architects, engineers, contractors, electricians, and public officials, took action and adopted the IECC 2009 Energy Conservation Code. Less than a year later on April 1, 2010 the new code went into effect across the state.

The new code applies to new home and commercial construction and to home and commercial renovation projects. By setting minimum standards for energy related building design and construction components, like windows and insulation levels, the new energy code ensures that buildings built or renovated today, will generate energy savings in a consistent and long-lasting manner for the life of that building.

The new energy code does more than save energy, it also saves money. According to an Institute for Market Transformation article on Building Energy Codes, for every $1 spent on energy code enforcement, there are $6 saved, and during the tough economic times who doesn’t want to save a little money? The new code also offers peace of mind to current occupants, because they can feel confident they are getting a safer and more comfortable home. Many of the benefits of building to the new energy code will be long-lasting. Because energy savings in a home are experienced over the life of the building, new occupants and future occupants will enjoy the energy savings, cost savings, and comfort and safety that come with a home built to the new code.

Not only is the energy code good for those occupying the property, the energy savings are also great for the environment. According to the BCAP (Building Codes Assistance Project), building homes and commercial properties to meet the 2009 IECC Standard and 90.1-2007, will help to avoid nearly 3 trillion Btu of primary energy use by the year 2030 and more than 0.2 million metric tons of CO2 on an annual basis by 2030.

The new energy code is obviously very important to property occupants and the environment, but what about all the players that are a part of the building designing, construction, and marketing process? . Below are just some of the groups that should be informed of the new energy code, and why it is critical that they be aware knowledgeable of the new code.

Architects, Engineers, and Designers- These professionals are responsible for designing residential homes and commercial buildings that adhere to the updated NH energy code established in the IECC 2009. They are the first line of ensuring that a future project be designed to meet the new IECC 2009 Energy Code Standards.

Contractors and Builders –They get to build to the new NH energy code established in the IECC 2009. It’s important for all NH Contractors and Buildings to have a thorough understanding of the new energy code, if they are going to build to it.

Code Officials- This group has the tough task of enforcing of the energy code. They need to know the new code inside and out to ensure all new buildings; homes and renovations are being built to the new standard established with the IECC 2009.

Realtors- Commercial and residential realtors are on the front lines working with sellers and buyers and advising them on their purchases. It is important that they understand that there is an updated NH energy code – the IECC 2009 – and the benefits of homes and buildings that are built to meet the new standard.

To learn more about the IECC 2009 Energy Code and to check out some great resources please visit our website at www.nhenergycode.com

Welcome!

Welcome to the NH Energy Code Challenge blog!  We hope to use this space to explore relevant issues and relay exciting developments related to energy codes in the state of New Hampshire.  This blog is for everyone – from policy makers to designers and architects, from builders  to homeowners and real estate agents.

We will also occasionally solicit guest contributors – experts in the field of energy efficiency and energy-related issues to give you insights into current building techniques, compliance methods, and the latest scoop in building energy code developments.

Got a question?  Leave us a comment and ask us!