This article was originally published in the January/February 1993 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.



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Home Energy Magazine Online January/February 1993




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Attic Insulation R-Values--Who's Fluffing?

In the highly competitive home building industry, successful builders learn quickly that to stay in business they must keep construction costs down. Unfortunately, some builders cut costs by skimping on energy features. That's because most energy measures are hidden from view, few consumers are knowledgeable in evaluating their effectiveness, and many consumers do not use energy efficiency as a significant criterion when purchasing a home.

Most states have building codes that mandate minimum energy standards, but they are often not rigorously enforced. Even utility-sponsored energy-efficient home programs may lack quality control measures to ensure that energy features are properly installed during construction. Poorly enforced codes hurt builders who are committed to energy efficiency and quality. They must compete against others who shortchange consumers, thus wasting energy and costing thousands of dollars over the life of the home.

One of the common areas to cut corners is the quality of installed loose-fill attic insulation. The R-value of loose-fill insulation depends upon its density, not just its thickness. Mixing excessive air with the insulation as it is blown onto the attic floor, a process known as fluffing, increases the insulation's loft and gives the appearance of greater material, and hence higher R-value. Simply measuring the thickness of loose-fill insulation cannot give an accurate measure of its R-value. The thickness and density must be determined

Cutting corners on loose-fill attic insulation became such a problem in Georgia that in 1989 the Georgia Chapter of the Insulation Contractors Assoc. of America approached the Governor's Office of Consumer Affairs (OCA) for help. Members of the association felt that some insulation contractors were installing less insulation than required by code, specified in contracts, or required in utility conservation programs.

It was the second time that the contractors association had received help from OCA. In the mid-1980s, OCA conducted a survey of over 500 homes and found that more than half had less insulation than claimed. Contractors and utilities were ordered to spend over $3 million to remedy the problem. It is illegal under federal and state law to misrepresent the R-value of insulation.

In 1990, OCA contracted with the Southface Energy Institute to conduct a second study of loose-fill attic insulation practices. Southface worked with David Yarbrough, chairperson of Chemical Engineering at Tennessee Technological University and a researcher at Oak Ridge National Laboratory, to develop an experimental design for the project.

We tested 827 houses, the majority of them built within the past three years. Houses were selected by distributing fliers from OCA throughout housing developments, mostly in the Atlanta area. The fliers explained the study and requested volunteers. Roughly 3% of the homeowners receiving fliers requested a free inspection.

In each home, an inspector mentally divided the attic into three equal sections, and from each section selected two places representative of that section. The inspector excluded sections within 8 ft of the attic entrance, near the eaves, and where the insulation had obviously been disturbed. The inspector took five thickness measurements at each of the six attic sites, using a long metal skewer and a scale accurate to 1 mm. At one place in each of the three regions, the inspector took an insulation sample using a cookie cutter, a metal cylinder approximately 1 ft in diameter and 2 ft tall.

Since this study was part of an official investigation of possible consumer fraud, the investigator placed each sample in a clear plastic bag, sealed the bag with evidence tape, and cataloged it with special chain-of-possession labels. The inspector filled the void where the insulation had been removed with a piece of R-30 fiberglass batt, and took the loose-fill sample to the laboratory to determine its R-value.

Approximately 25% of the houses tested had measured R-values at least 20% less than claimed. The estimated value to consumers of the wasted energy due to the attic insulation shortages was over $145,000 each year, or $177 per house per year.

One in four houses had deficient insulation levels, but this is an improvement compared to the 1989 study, where over half of the homes tested were underinsulated. The study indicates that quality control is improving. In addition, nearly half of the houses tested had attic insulation R-values that were greater than claimed! Attic blowing is not an exact science, and it is possible that the better contractors over-insulate to ensure meeting contracted values.

Approximately 95% of the houses tested had loose-fill fiberglass insulation, and the remainder loose-fill rock wool and fiberglass batts. No houses in the survey had loose-fill cellulose.

The OCA is currently negotiating resolution of the insufficient insulation problems with builders and insulation contractors who the study discovered had provided less R-value than claimed. Possible actions include:

  • testing and retrofitting all homes in a given subdivision, or homes insulated by the builder or insulation contractor

  • restitution to homeowners for lost utility costs

  • reimbursement of OCA's investigative costs

  • civil penalties.


Even before negotiations began, at least one builder of houses in the target area began offering free attic insulation inspections and retrofits.

According to Barry Reid, the OCA is extremely pleased with the outcome of the investigations and the fact that Georgia consumers have received millions of dollars worth of insulation retrofits and restitution. The next step is a more comprehensive investigation of adherence to the Georgia Energy Code. OCA has contracted with Southface to study a variety of energy efficiency measures required by code, such as sealed ductwork for forced-air distribution systems, sealed penetrations in the building envelope, and proper slab insulation.

--Dennis Creech and Jeff Tiller

Dennis Creech is Executive Director of the Southface Energy Institute, a non-profit energy eduction and research organization. Jeff Tiller is the institute's president


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