Efficiency, Recycled Insulation

ADVERTISEMENT

Reducing Waste

Whether you use electricity, natural gas, oil, or another energy source, at least half of the fuel consumed goes for space conditioning—in other words, heating and cooling. That’s because some of the indoor temperature leaks outside, and the outside temperature leaks in. To gain better control over your indoor atmosphere and reduce your energy costs, make sure you have the right kind of insulation, and enough of it in the right places.

Choosing an Insulating Material

When most homeowners think about insulation, they picture fiberglass batts. This makes sense, because fiberglass insulation is practical, affordable, and relatively easy to handle. By comparison, loose fill insulation involves more effort and sometimes more expense. Once the insulation is installed, however, loose fill has several advantages that make it worth the trouble.

The first of these is recycled content. Loose fill insulation can be made from

• Recycled paper: The most abundant material available for recycling.
• Mineral wool: Either the manufactured material called rock wool or the metal by-product slag wool.
• Fiberglass: It can be reclaimed from previously discarded insulation.

Loose fill is either blown in to confined areas such as attics and crawl spaces, damp-sprayed into wall cavities, or poured into areas where access is easier. Moisture is sometimes added to the loose fill to keep the material from blowing where it doesn’t belong. This evaporates
quickly once the insulation has settled.

One weakness of cellulose insulation is that it can absorb more moisture than most other types of insulation. If it doesn’t have a chance to dry out again, it will lose some of its effectiveness and perhaps become a place for mildew to grow.

Reducing Waste

In some ways, loose fill is only on par with fiberglass batts. For example, they all have roughly the same fire ratings, and cost about the same for the amount of R-value they provide. Factor in the recycled content, and the balance tips toward loose fill. Then take into account the potential health hazards, and the recycled products look better still. For the greatest number of environmental benefits, consider cellulose insulation.

Not only is cellulose insulation made from up to 80 percent recycled fiber, it can be recycled again. By using cellulose loose fill, you keep unwanted air and sound out of spaces in your house, and keep cardboard and paperboard out of landfills.

Made from paper products and wood fiber, cellulose insulation fills in spaces large and small. It can be packed into tight places, such as the points at which the roof decking and rafter ends meet the ceiling joists. It can be laid down in thick blankets where there’s more room, and gravity is on your side. The insulating value of cellulose loose fill is about R-3.7 per inch. It guards well against sound transfer, too.

Protecting Health

The binders used in most fiberglass insulation contain formaldehyde, which is widely considered harmful to your health; its vapors are classified as potential carcinogens. Once installed, fiberglass can still emit formaldehyde gases. Fiberglass is also listed as unhealthy, both for the long-term effects of exposure to airborne particles, which some sources consider another possible cause of cancer, and the immediate result of respiratory irritation.

To make cellulose loose fill more resistant to fire and infestation, manufacturers use chemical additives. Up to 20 percent of cellulose insulation is made of ammonium sulfate or boric acid, both of which are low in toxicity. Ammonium sulfate gives off a stronger odor, and some installers believe it may corrode copper pipes. Boric acid, meanwhile, is also used in baby clothes and cotton batts as a fire retardant; it is less likely to cause irritation.

If you’re concerned about the potential health hazards of these additives, either during installation or afterward, ask the manufacturer or retailer for health and safety information—or check for competing products.

Hidden Hazards

When you evaluate your existing insulation, watch out for vermiculite— a lightweight mineral shaped like grains or nuggets, in colors that range from gray-brown to silver-gold.

Vermiculite was commonly used as loose fill insulation in houses built before 1990. Some contain asbestos, which is well known as a carcinogen. If asbestos fibers are released into the air and inhaled, they can lead to serious respiratory illness or cancer. The threat to your health is great enough that the U.S. Environmental Protection Agency (EPA) has issued a warning about vermiculite insulation.

If you find vermiculite in your house, call an insulation professional for advice. You may have to decide between having it removed by a licensed contractor and just leaving it where it is. For more information, visit the EPA web site at www.epa.gov and type “vermiculite” in the search box.

Installing Loose Fill

While fiberglass batts have the same R-value as cellulose loose fill, they are made in fixed widths and thicknesses. Any variation in the space you fill with fiberglass batts may prevent them from forming an adequate barrier to air infiltration and high-frequency sound transmission. Remember: the R-value of a gap in your insulation is zero.

Loose fill, however, conforms to every bump and dent, sealing the space with as much material as you choose to apply. Over the months and years, cellulose insulation settles further in, which improves its thermal performance. That also means the installed depth must be adjusted for the predicted density once the loose fill has settled, not just the total depth at the time of installation. Don’t worry about making these calculations; manufacturers provide them in their product literature, and sometimes right on the bag.

For installations in open wall cavities, you will need to use a damp-spray method. While this may be within the range of skill you already have, the requirements are strict and the consequences of mistakes can be serious. The dampened mixture should not have more than 25 percent moisture when it is enclosed, and will need enough ventilation to finish drying out. Otherwise, mold and mildew become likely. This is one project you should probably give to a professional installer.

The installed price of cellulose insulation can be higher than for fiberglass batts, because loose fill requires special equipment to reach tight spaces. As a percentage of total building or remodeling costs, however, this difference in price is relatively small. Given the performance characteristics of loose fill, you will save that much and more in heating costs over time, without even calculating the value of environmental and health benefits.

Finding Your Number

To determine how much insulation you need, ask your local housing inspection agency or power utility for recommendations. Another valuable source of information is the Home Energy Saver, an online calculator created by the Lawrence Berkeley National Laboratory. It’s
available at http://hes.lbl.gov.