Rather than all of the patchwork, here is my more comprehensive view on the subject:
Background: My company sells and installs insulation and weatherization products. We purchase and work with these products on a daily basis. We work with various state and local energy efficiency programs, and have a BPI certified energy consultant on staff... Don't mean to advertise here, just establishing where I'm coming from on this.:thumbsup:
Price: I pay less(and charge less) to install blown cellulose than blown fiberglass. I purchase these products wholesale so the pricing may be different to a retail DIY'er, but the overwhelming sentiment that I hear and see is that retail pricing is consistent with that: Cellulose is slightly cheaper in a "blown-in" attic application. Other projects such as new construction, walls, etc could be a different story. Our business is primarily retrofit in existing homes, but I would venture to guess that fiberglass batting is probably cheaper to insulate new construction than a cellulose BIB system or something along those lines.
Performance: Both get the job done. There are some aspects of cellulose that I prefer including versatility (same product can be blown, dense packed, etc), it offers more resistance to airflow, and my installers say that it is more pleasant to work with . We install blown fiberglass upon request or in circumstances where it makes more sense such as going over existing Fg, but all things equal I choose cellulose.
The home performance community including insulation professionals, energy consultants, etc overwhelming prefer cellulose. Most roofing contractors etc, like fiberglass. This is speculation on my part, but my thought as to their reasoning is that selling an Owens Corning roof AND insulation system is very compelling, and makes a nice package. The builder supply houses also carry and promote that product, while cellulose typically is only available at specialty insulation suppliers (other than the box stores of course).
Health/Safety/"Green factor": There are reports on both sides showing that each one is healthier, safer, and "greener", so it is really impossible to say for certain. There are some things that each is slightly better at as well, but in the end, they are not too far off. My own personal preference is again for cellulose. It has a higher content of recycled material, takes less energy to make, and IMO is the lesser of the two evils in terms of health hazards.
The following is a summary of an extensive Natural Resources Defense Council (NRDC) report. The NRDC is a non-profit environmental membership organization with over 300,000 members and contributors nationwide:
The NRDC has concluded the following:
Cellulose insulation manufactured from recycled paper is the least polluting and most energy efficient insulation.
Cellulose has the highest post-consumer recycled content. The fiberglass industry averages 35% recycled glass, while the cellulose industry averages a minimum of 75% recycled content.
It takes more than 10 x’s as much energy to produce fiberglass insulation as cellulose insulation.
Due to air circulation and natural convection, the R-value of blown-in fiberglass insulation decreases by as much as 50% as the temperature drops from 45 degrees F to 18 degrees F.
Cellulose has better resistance to air flow and prevents the upward movement of air caused by temperature differences (the R-value of cellulose actually improves during cold weather).
Substantial and well-documented public health threats are associated with fiberglass.
No adverse health effects from cellulose insulation have been identified.
Summary: Anyone researching the topic will notice in less than 5 minutes that each side has more studies and conflicting info than one could ever read. In the end, each product has minor pros and cons, and both do the job effectively.
If you are a consumer reading this: STOP STRESSING OVER IT!:laughing: Just get it done, and make sure that you air seal as well!:thumbup:
. Cheaper: yes. I don't care how many bundles/packages/lbs are used, please show me an insulation contractor that charges less for FG for the same R-value at the end of the day. You can't because FG costs more. PERIOD. In addition:
