duct leakage

How Duct Leakage Steals Twice

Posted on April 21,2015 by ab3 in air leakage

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.

Can’t Anyone Get Things Right?

Posted on April 21,2015 by CarlSeville in duct

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.

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

Posted on April 21,2015 by ab3 in backdrafting

Indoor air quality (IAQ) 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.

All About Furnaces and Duct Systems

Posted on April 21,2015 by user-756436 in condensing furnace

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.

Thou Shalt Commission Thy Ducts!

Posted on April 21,2015 by ab3 in air conditioner

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.

New Videos: Sealing Ducts and Installing Dense-Packed Cellulose

Posted on April 21,2015 by GBA Team in cellulose

GBA 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 NESEA's Building Energy 13 conference in Boston.

How to Install Flex Duct Properly

Posted on April 21,2015 by ab3 in Air Diffusion Council

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.

Good Ducts, Bad Ducts

Posted on April 21,2015 by CarlSeville in duct

Whether they actually do it or not, I think almost everyone involved in high performance buildings recognizes that the best place to put our ducts is inside conditioned space. Most builders in my area haven’t made the change, and with the exception of the occasional house with an insulated basement, they still put most air handlers and ducts in the attic.

Why Don’t More HVAC Contractors Own Duct Leakage Testers?

Posted on April 21,2015 by ab3 in Bailes

HVAC contractors own a lot of equipment. Of course, they have pressure gauges to test refrigerant charge in air conditioners and heat pumps, and many more pieces of technical equipment. One piece that few contractors own, however, is a duct leakage tester. With more and more state energy codes requiring duct leakage tests, doesn't it seem obvious that HVAC contractors need to be like plumbers and test their own work before passing it off?

Cool Tool for Duct Testing

Posted on April 21,2015 by CarlSeville in Duct Blaster

Some days I like my work, and some days I don’t, but I guess that’s just the way the world is. This love/hate relationship really rears its ugly head when I have to go out and do blower door and Duct Blaster testing on homes. It’s not one of my favorite things to do, but if the weather’s nice and the drive’s not to far, it can end up being a good, and reasonably profitable, day.

Utilities Offer Programs That Can Benefit Your Customers

Posted on April 21,2015 by michaelds in air leakage

In Texas, as in many other states, local electric utilities offer homeowners a variety of free services to help lower energy bills.

Will Minisplits Replace Forced-Air Heating and Cooling Systems?

Posted on April 21,2015 by user-756436 in airflow

Because forced-air heating and cooling systems are assembled on site from a great many parts, there are many ways for installers to make mistakes. Researchers have repeatedly shown that a high percentage of residential forced-air systems have major problems, including duct systems that are poorly designed, poorly located, and leaky. Other problems include incorrect refrigerant charge and too much or too little airflow over the cooling coil.

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

Posted on April 21,2015 by user-756436 in duct

Most residential duct systems have numerous leaks that waste energy and lead to room-to-room pressure imbalances. Unfortunately, though, few building inspectors outside of California bother to enforce existing code requirements that residential duct seams be sealed with mastic or high-quality duct tape.

Duct Leakage Testing

Posted on April 21,2015 by user-756436 in Duct Blaster

For years, Americans who would never put up with leaky plumbing pipes have been willing to accept leaky ducts. While water damage is hard to ignore, the damage caused by leaky ducts is more subtle. Yet leaky ducts not only waste huge amounts of energy — they can also lead to comfort complaints, moisture problems, mold, and rot.

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