duct leakage

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A Few Pressure Testing Tips and Tricks

Blower door and duct leakage testing can be easier if you use these techniques

Posted on Sep 9 2015 by Allison A. Bailes III, PhD
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A typical BPI Building Analyst spends four to five days in a class learning how to do blower door testing, along with all the other stuff they need to know. HERSIndex or scoring system for energy efficiency established by the Residential Energy Services Network (RESNET) that compares a given home to a Home Energy Rating System (HERS) Reference Home based on the 2006 International Energy Conservation Code. A home matching the reference home has a HERS Index of 100. The lower a home’s HERS Index, the more energy efficient it is. A typical existing home has a HERS Index of 130; a net zero energy home has a HERS Index of 0. Older versions of the HERS index were based on a scale that was largely just the opposite in structure--a HERS rating of 100 represented a net zero energy home, while the reference home had a score of 80. There are issues that complicate converting old to new or new to old scores, but the basic formula is: New HERS index = (100 - Old HERS score) * 5. raters get all that, too, but also have to learn how to do duct leakage testing. Then there’s that whole big bunch of people who have gone through one or two day intensive blower door and duct leakage training for energy code compliance. When they’re done with the training, how do they figure out how to do pressure testing in the real world?


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Image Credits:

  1. Energy Vanguard

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How Duct Leakage Steals Twice

Where duct leaks occur matters as much as how much leaks

Posted on Jul 23 2014 by Allison A. Bailes III, PhD

Duct leakage is a big deal. It's one of the top three energy wasters in most homes (air leakage and cable TV set-top boxes being the other two). Researchers at Lawrence Berkeley National Lab found that duct systems leak on average about 10% of the supply air they move and 12% of the return air. (Download pdf and also see Dana Dorsett's comment below, #1.) In far more homes than you might suspect, the main culprit is a disconnected duct, as shown in the photo at right, but a typical duct system has a lot of other leaks, too.


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Image Credits:

  1. Energy Vanguard

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Can’t Anyone Get Things Right?

Recent experiences with contractors and tradespeople leave me frustrated

Posted on Apr 14 2014 by Carl Seville

In my business of certifying buildings, most of my work involves working with architects, contractors, and trade contractors who are trying to create green buildings. Unfortunately, they frequently miss the mark in some key areas.

Many of them are well intended but don’t have a broad enough view of their projects. Others only do the minimum required to meet a green building standard forced on them by someone else. And a few, thankfully, seem to get it and work hard to do the right things.

This post, the first in a series about problems I run across, will focus on HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building..


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Image Credits:

  1. Carl Seville

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Four Ways Bad Duct Systems Can Lead to Poor Indoor Air Quality

Higher energy bills and lower comfort levels may not be the worst of your problems with faulty ducts

Posted on Apr 9 2014 by Allison A. Bailes III, PhD

Indoor air quality (IAQIndoor air quality. Healthfulness of an interior environment; IAQ is affected by such factors as moisture and mold, emissions of volatile organic compounds from paints and finishes, formaldehyde emissions from cabinets, and ventilation effectiveness.) is a big deal. It doesn't get nearly as much attention as energy efficiency or green building programs, but it should be one of the highest priorities for anyone who breathes air and spends time indoors.

It's actually part of an even bigger deal called indoor environmental quality (IEQ), but I'm just going to focus on IAQ here as I show you four ways your ducts might be hurting your indoor air quality.


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Image Credits:

  1. E3 Innovate

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All About Furnaces and Duct Systems

Most forced-air heating systems are still poorly designed and installed

Posted on Jan 24 2014 by Martin Holladay

UPDATED on October 2, 2014 with more information on duct system design.

Many different appliances can be used to heat a house, including boilers, water heaters, heat pumps, and wood stoves. However, most homes in the U.S. are heated by a forced-air furnace.

These devices are connected to ducts that deliver heated air to registers throughout the house. Different types of furnaces are manufactured to burn a variety of fuels, including natural gas, propane, oil, and firewood. The most common furnace fuel in the U.S. is natural gas.


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Image Credits:

  1. AHRI

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Thou Shalt Commission Thy Ducts!

If you don’t commission new HVAC systems in high-performance homes, you’re gambling with callbacks

Posted on Sep 11 2013 by Allison A. Bailes III, PhD

The typical new home gets a heating and air conditioning system that's about two times too large. I've  discussed oversized air conditioners many times before.


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Image Credits:

  1. Energy Vanguard

Video: Duct Sealing and Leak Testing

Duct sealing and duct leakage testing: Two experts from Conservation Services Group, Eric Wilder and Will D’Arrigo, explain how to seal duct seams with mastic and how to use a Duct Blaster to test duct tightness

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Produced by Dariusz Kanarek and Mike Dobsevage; edited by Robin Burkin


OTHER VIDEOS FROM THE NESEANorth East Sustainable Energy Association. A regional membership organization promoting sustainable energy solutions. NESEA is committed to advancing three core elements: sustainable solutions, proven results and cutting-edge development in the field. States included in this region stretch from Maine to Maryland. www.nesea.org CONFERENCE

Video: Dense-packed cellulose

EDITOR’S PICKS

Duct Leakage Testing

Sealing Ducts: What’s Better, Tape or Mastic?

How to Track Down Leaks in Forced-Air Ductwork

Keeping Ducts Indoors

How to Install Flex Duct Properly

Fine Homebuilding: Testing and Sealing Ductwork

CONSTRUCTION DETAILS

Air seal at duct boot

Recorded at the demonstration stage at NESEANorth East Sustainable Energy Association. A regional membership organization promoting sustainable energy solutions. NESEA is committed to advancing three core elements: sustainable solutions, proven results and cutting-edge development in the field. States included in this region stretch from Maine to Maryland. www.nesea.org's Building Energy 13 conference in Boston on March 6, 2013, duct sealing experts Eric Wilder and Will D’Arrigo explain how to seal leaks in duct seams and how to conduct a duct leakage test.

Among the questions answered in this video:

  • Are any tapes durable enough for duct sealing?
  • When should I use mastic, and when should I use tape?
  • What kind of mastic should I use?
  • When should mastic be applied with a paint brush, and when should it be applied with a trowel?
  • Are there any changes to code requirements for duct sealing on the horizon?
  • Can I use a fogTo fog a room or building is to use a fog machine during a blower door test, revealing locations of air leaks where the fog escapes. The fogging material is usually a glycol-based solution, completely non-toxic. machine for duct leakage testing?
  • Are ducts tested at 25 pascals or 50 pascals?

Once you've seen duct sealing in action, and you've heard some of your questions answered by these two experts, you'll have the confidence to tackle duct sealing at your next job site.

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New Videos: Sealing Ducts and Installing Dense-Packed Cellulose

GBA presents two new videos, both recorded at NESEA's Building Energy 13 conference in Boston

Posted on Apr 17 2013 by GBA Team

GBAGreenBuildingAdvisor.com has released two new videos: one on installing dense-packed cellulose in stud cavities, and the other on sealing duct seams with mastic.

Both videos were recorded in March 2013 at NESEANorth East Sustainable Energy Association. A regional membership organization promoting sustainable energy solutions. NESEA is committed to advancing three core elements: sustainable solutions, proven results and cutting-edge development in the field. States included in this region stretch from Maine to Maryland. www.nesea.org's Building Energy 13 conference in Boston.


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  1. GBA video

Video: Duct Sealing and Leak Testing

Duct sealing and duct leakage testing: Two experts from Conservation Services Group, Eric Wilder and Will D’Arrigo, explain how to seal duct seams with mastic and how to use a Duct Blaster to test duct tightness

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How to Install Flex Duct Properly

Following the Air Diffusion Council's standards would lead to better installations

Posted on Mar 13 2013 by Allison A. Bailes III, PhD

I've written a lot about duct problems (especially those in flex duct) because they're so abundant. A couple of years ago, I even wrote an article in the Energy Vanguard Blog about whether or not flex duct should be banned. My answer was no — but that we need better quality control.


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Image Credits:

  1. Energy Vanguard
  2. Air Diffusion Council
  3. Robert Bean

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