www.energystarhomesamerica.com

Issue 5 Volume 3

May 2005

Infrared Thermography
by Rogge Miller

GWSSI has recently acquired the newest technology available to add to our ever-growing repertoire - an infrared camera. The infrared camera was the next natural step in a progression to stay ahead of the industry.  In many markets, this technology is still unavailable and places GWSSI in a unique leadership position.  There is a substantial learning curve associated with infrared thermography, but GWSSI has sent several key employees through extensive infrared training.  As a result, GWSSI is developing a program to train and certify individuals throughout the company.  This technology has proven to be invaluable in detecting unseen damages and defects.
 
First, let me describe how an infrared camera works. The primary function of these cameras is to detect thermal differences.  Our particular camera can detect temperature differences as low as 0.25ºF.  Pretty good, huh? The primary question for you the builder is either “so what” or “what will this new contraption do for me?”  From the residential side of the applications available, three come to mind immediately: moisture, air leakage and insulation. 

Moisture intrusion is one of the occurrences all builders dread. The simple explanation is this:  wet walls have a different temperature than dry walls.  The camera allows us to immediately find areas suspect of containing moisture without doing any kind of destruction to the wall. Once the areas are tagged, we can then extend the investigation through the use of either a destructive or nondestructive moisture detector. Keep in mind that even the destructive moisture detector uses two pinprick probes that are not visible to the eye unless a very close examination is done of the wall.  These two tests used in conjunction with each other are invaluable at locating moisture in any wall cavity or under the insulation on a ceiling.

The same principle works with insulation that works with moisture: well-insulated walls have a different temperature than poorly insulated walls. Two of the areas showing numerous problems with the installation are sloped ceilings and bonus room floors over a garage or other unconditioned area. Sloped ceilings, especially those using batts inset stapled, can show to be from 20% to 70% uninsulated. The inset stapling places the batts one to two inches away from the sheetrock allowing very cold or very hot attic air to intrude into these areas. More often than not, garage ceilings are insulated instead of bonus room floors. Then if the ceiling joists under the bonus room are not blocked, the very hot or cold attic air enters these joists between the floor and the insulation and you have an uninsulated floor. In both cases, these heating and cooling loads were not taken into account when the load calculations were done and in some cases these insulation problems can actually be the cause of comfort complaints.

And when air enters a house from the outside, the surfaces it hits become either colder or hotter depending on the temperature of the air.  This pattern can easily be seen as “fingers” that begin with the temperature of the air leaking in and then slowly fading to the inside temperature of the interior surfaces.

There are numerous other uses for these cameras that GWSSI will be exploring:  electrical systems (from residential breakers to substations), mechanical (from excessive friction to non-uniform heat flow in casting operations and ovens and much more), moisture intrusion under certain types of flat roofs, levels of liquids and sludge in large storage tanks, and the list keeps growing.

If you have specific questions about this technology or its availability in your area, please call the corporate office at 405-888-0206.  And in the meantime, Think Thermally!    

Inspector’s Corner
Insulation Installation and the Effective R-Values
by Bernardo Lopez - Regional Manager

What is the correct way to install insulation on walls and ceilings? What in the world does the term “effective r-value” mean? These two questions have very high importance when it comes to the comfort of a homeowner inside his home. With today’s energy-efficient homebuilding practices, the need to have correct insulation installation and correct r-values has become as important as having an HVAC system or water in the home. Now, to answer these questions we must first go into detail and understand how insulation works.

       First, we will address the installation of insulation process. The four most common mistakes made during insulation installation are gaps, voids, compression of the insulation, and misalignments between the air barrier (sheetrock) and the insulation. Gaps are spaces in the cavities due to plumbing pipes, electrical wires, and vents that the installer did not cut around to make sure insulation filled all the air space in the walls. These gaps have the potential to allow convective currents or heat gains in the walls and reduce the resistance of the insulation. The installer should make sure the cavities are completely filled and the insulation is cut around to fit any objects inside the walls. Voids are areas that have no insulation at all. These areas are usually found behind kitchen blocks installed at frame stage for proper support for the cabinets at the final stage of the home construction. The simplest way to reduce voids is to make sure insulation is installed where it is needed. Another factor is compressed or squashed insulation that has a reduced r-value. The r-value is devalued because the number and size of air pockets within the insulation has been reduced. Insulation should not be compressed to fit in a wall cavity that it is not designed to fit. The following chart is a sample of the most common r-values and what wall thickness it correspond to.

4in.     2x4 wall stud ……………….r-13 0r r-15

6 in.    2x6 wall stud ……………….r-19

10 in. 2x6 with a 2x4 furr out……...r-30

10 in. 2x10 wall stud ………………r-30

The fourth issue to address is misalignment between the insulation and the air barrier. The insulation and air barrier should be installed in direct contact with each other. When misalignments are present, heated air is able to bypass the insulation where convective currents may form and transmit heat to the conditioned surface of the air barrier.

The correct way to eliminate this problem is to install the insulation in direct contact with the air barrier.

     We will now move on to finding the definition of an effective r-value. R-value is defined as the ability of a material to resist heat flow. The effective r-value pertains to the ability of a material to resist heat flow if certain aspects are done correctly. For example, if batt insulation is rated with an effective r-value of r-13 but it has gaps, voids, compression, and misalignments then the insulation now has a lower effective r-value.

Energy Design Update reported that research conducted by the National Research Council of Canada found that small gaps in fiberglass batts installed in a wall can cause as much as 32% loss in r-value at –30.0 f. They measured an r-value loss of 4.6 (an installed r-value of 14.4) at 23.0 f. So, in conclusion the effective r-value labeled on some insulation packages is not always what you get unless proper installation is done. If you would like more information or some insulation inspection services please feel free to contact Guaranteed Watt Saver at 1-888-488-0206

Announcement:
GWSSI’s Donney Dorton is now certified to do Commercial Plan Analysis.  Donney is a certified Commercial Energy Plans Examiner for Energy Compliance.

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