However, there’s some strongly biased and false information here. “Shredded-up newspaper is highly flammable, pests like it, water loves it, and it can get nasty and moldy.” Cellulose insulation, in addition to having the lowest embodied energy, is treated with non-toxic (to humans) borate which is an excellent fire-retardant, kills most household insects, is an irritant to rodents and prevents mold growth. The fact that it is one of the most hygroscopic of all insulation materials means that it serves as a moisture buffer, absorbing and releasing excess humidity as necessary, and by distributing the moisture throughout its mass it prevents the localized high moisture content which leads to mold and rot in the wood framing and sheathing.

Blue Jean batt “installs quickly, comfortably and easily – requiring no special equipment…” Recycled blue jeans create one of the most eco-friendly batt type insulations, but it’s susceptible to the installation problems of all batts – difficult to fit completely into cavities. Additionally, blue jean batts are nearly impossible to cut, even with the special knives and saws that are recommended for that purpose.

Insulation overviews like this would be more useful if they were based on fact rather than opinion.

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We are always open to trying something new for our customers yet unfortunately often the new/returning options are generally 2-4 times the cost of blown in cellulose. These include Eco Foam, Air Krete, Spray Foams, recycled denim batts, wool batts, etc. And Aerotech Gels are most likely going to be much more expensive. Most of our customers cannot afford these other options, especially with the way the economy is today.

The one we have found that makes the investment worth it in terms of energy savings/payback is the Eco Foam for walls. It provides the air sealing, insulation, and sound reduction qualities that we are looking for as a Home Performance contractor.

Also the issues I have seen mentioned in the comments such as indoor air quality and moisture issues of cellulose or fiberglass – these are issues with any insulation. Any fiberous items floating around in your home\’s air is not good to breathe, and there is a simple and highly cost effective answer – air sealing. Air sealing is part of Home Performance 101 and goes hand in hand with any insulation product that is not sprayed into place. Any type of batt or loose fill insulation has millions of air spaces that allows air to leak in/out of homes by traveling through and around the insulation. Air sealing with a combo of caulk, spray foam or rigid foam board insulation should happen first before any batt or loose fill insulation is installed. It is the air sealing that will keep any nasties from migrating from your attic, walls and crawlspace from making into your home.

Pest are another indoor air quality issue that has nothing to do with insulation. If you have pests in the attic or crawl, then they need to be removed and you need to find where they are coming in and block off the hole(s).

Regarding insulation and moisture issues, almost all types of insulation will get moldy and nasty if water penetrates and sits around in the material. Think about having soaked denim cotton jeans and cotton sleeping bag on backpacking trip where its pouring down rain – they don\’t dry out until it stops raining and the sun comes out. If your walls, attic, and crawlspaces are getting that much water, then you have another issue that has nothing to do with the insulation. Insulation is NOT an air or moisture barrier, you have to take into account your climate and region in order to design in where the vapor barriers are installed in the roof and walls. If they are on the wrong side then your home will experience the diaper effect – moisture locked in and no where for it to go.

By far the most common insulation we use for attics and walls is cellulose for several reasons:
1. Its about the same price as blown in fiberglass so its an easy & comparable sell to home owners that believe in more traditional products such as blown in fiberglass. And it is much more environmentally friendly and non-toxic for the home.
2. It has a high R-value at approx. 3.7 per sq inch
3. It deals with moisture by dispersing it over a larger area which dries out more quickly later, whereas fiberglass and wool products wick it to the edges where it can pool up in the lowspot and stay stagnant for a long time depending on how much moisture is leaking in.
4. Cellulose is treated with a boric acid solution – the type and toxicity depends on the boric solution used & there is more than one out there. Ask your insulation manufacturer or contractor about seeing an MSDS sheet. In general boric acid solution is non-toxic as compared to the bromines and other fire retardants out there. It also is used to deter insects (a great natural remedy for ants & other small insects that infest our walls)
5. Cellulose can be dense packed into walls and there are less air spaces than with blown in fiberglass, wool or denim batts. This means it has better sound reduction and air sealing properties.

we people living in the tropics utilize the use of air as insulation to walls and roof. as much as possible we integrate it to our designs. air is abundant and it is always free to use.

we people living in the tropics, we utilize air spaces as insulation. you can verify it. air is still the best insulation.

A company I have talked to here in Oregon, Phelps, that uses it, says that moisture is not as much of a problem because water slowly passes through it. So if your roof is leaking, you\’re going to see the leak, but the icynene doesn\’t retain the water the way the way

Lastly:Good article. I am not an insulation contractor, I\’m a nurse practitioner, and did my master\’s on a subject related to home air pollution (chlorpyrifos exposure). Most people don\’t realize they get most toxic exposure inside, not outside, their homes, so it is important to consider the toxicity of anything you use/bring into your home. Remember that substances you use indoors are going to be MUCH more concentrated than those you use outside. Personally I try not to get paranoid, but I avoid anything containing old-fashioned particle board (offgases formaldehyde and other things) and I painted my rooms with low voc paint.

It\’s important to consider Hypocrates\’ maxim: the difference between a medicine and a poison is in the dose. Regarding cellulose and their borate content: Boric acid is fine if you use a bit of it for medicinal purposes or to kill ants. I don\’t know if it has health effects if it is floating around in your indoor air constantly. I wish it was easier to get information on the toxicity of everyday products. Seems there should be some trusted website you could go to. If you know of one, please tell me! And info on icynene, please!

Thermal energy (heat or cold) moves in three ways; conductivity, radiation and convection. Unfortunately, our present building code only address’s radiation (R value). A truly effective insulation material should be able to mitigate all three of these. When taking a closer look at convection we find the biggest culprit of thermal energy loss; air infiltration. Only spray foam insulation can address all three forms of thermal energy transfer (especially air infiltration) while still maintaining Class I fire rating.

I pose no marketing bullets here or try to make something out that it is not. Science is science. Adhesion and expansion is how spray foam performs the best.

I own a spray foam insulation company (www.ecologicinsulation.com). You can call my above statement biased because of this or lift the vail from your eyes and see the light. If you want to save money on heating and cooling bills and reduce your pollution output spray foam is the answer.