There are three types of insulation that are being used in today’s market. The well informed homeowner understands there are pros and cons of each of them and here’s what they are:
Settling: Most insulation settles and since it settles, it means you will have a lower R-value. (R-value refers to resistance to temperature changes. The lower the R-value, the lower the insulting benefit.)
Moisture Buildup: When some products become damp, due to improper ventilation or ice damming, mold can develop on it if it is a natural product.
Here are the types of insulation most common for attics and wall cavities:
Foam: This is a very durable product that provides air sealing in an area of the home that most people overlook. Many insulation companies are not offering it as it requires additional specialized training and the 2 part chemicals can be difficult to apply to the untrained. This type of insulation gives you the highest R-value per inch, but it also is the most expensive. If the wrong type of foam is used in the wrong areas, it can create a problem rather than fix it. Check your local building codes as it is likely to require an additional type of insulation on top of it if used in an attic or wall cavity.
Fiberglass: Quickly becoming the industry standard for attics, fiberglass has great insulation properties but some of the products out there settle and create a lot of itching if you ever need to access your attic. On the plus side, there are new technologies out there that use long-strand fiberglass instead of short fiber. The longer fibers have a better R-value and this product doesn’t settle.
Cellulose: Effectively this is ground up, recycled paper which, from an environmental perspective, is a plus. The biggest problem with this product is that it settles fairly significantly and is treated with borax to retard fires. Proponents market this as a green alternative, but the chemicals sprayed upon it can negate it’s green benefits. Cellulose can be a good product for people who are vigilant with the maintenance of their roof and have a simple roof line that tends to not be as prone to leaks as multi-faceted roofs (more than 6 facets). The reason for this is that it will absorb moisture which could create mold.
Denim: Likely the greenest of all insulation, it is ground up blue jean material is putting a layer of ground up fabric across the entire attic. Although it is a recycled product, it tends to be a little pricey and is not terribly common.
Worth mentioning
Rock wool: Installed in batts, this spun stone product is very green and naturally fire resistant. In certain instances it is a superior product to others for walls. It has limitations with attics as rock does not fluff up as is required by todays insulation blowers to create a non-seamed blanket over an entire conditioned attic space.
Hemp: As of this writing, hemp insulation is coming on the market. This of this as a wood fiber product. It is super strong and is being used in sheets and batts in certain areas where it is available. This is not available to most insulators yet but, as technologies change, it is worth keeping an eye on for the future.