Cellulose, fiberglass and home insulation

STOP GLOBAL WARMING
Save energy and money

Cellulose & House Insulation

Fiberglass insulation is a reference material that insulates around 90% of North-American new homes. But there are other good alternative insulations, namely sprayed foams, mineral wool, and cellulose. This page deals with cellulose, comparing it to fiberglass. See Fiberglass and Mineral wools, for details about fiberglass and mineral wool insulation.

Cellulose is mostly made from recycled newsprint, cardboard, paperboard and other waste paper products treated with chemical to obtain a fire-resistant and insect-resistant material. Cellulose is presented as loose-fill or as a wet-sprayed material.

Cellulose and the environment

Cellulose has environmental advantage over fiberglass (and mineral wools or plastic sprayed foams). Cellulose is a typical “green” home product , with a much higher recycled content. Besides, it’s a superior air sealer and has superior acoustical properties and a more friendly chemical composition.

Note:
The potential health risk posed to installers is lower than that of fiberglass insulation, but it exists. So, be careful, when installing cellulose insulation in your home. Use the manufacturers requirements.

Performance of Cellulose insulation

Tightly packed cellulose insulation is more thermally efficient than fiberglass ones. Although cellulose insulation’s R-value (around 3.7 per inch) is very similar to hard fiberglass batts, it has a big advantage over fiberglass: cellulose blocks air leakage through cracks, void and gaps in a particularly efficient way (only surpassed by sprayed synthetic foams), avoiding significant heat losses.

Uses of cellulose insulation

Cellulose is used in home's attics (dry cellulose fiber or damp fiber) and walls (usually damp fiber, sprayed into the wall cavities). Dry-blown cellulose is more common in home retrofit applications, namely in attics.

The price of cellulose insulation

It varies a lot, but cellulose is usually more expensive than fiberglass in home applications. Costs are often close to that of synthetic sprayed foams for homes: between 1 and 2 times the price of fiberglass insulation.

Cellulose and Fire Rating

Some people say that cellulose insulation presents a reasonable fire-risk for homeowners. However, the fact is that cellulose has been approved by all house codes, while official tests confirm that cellulose is fire-safe.

Experts explain that the particularly tightly cellulose fibers prevent air combustion and the spread of fire through walls and other cavities or gaps of the house.

Mildew and cellulose insulation

Cellulose insulation can absorb more moisture than most other types of insulation. If wall cavities aren’t perfectly dry, or if there is the risk of wetting, then cellulose may favor mildew growth. Well designed and implemented walls and attics are essential to the use of cellulose insulation. If this isn’t possible, then you should look for other solutions.

Cellulose installation

The quality of the installation is crucial, and that demands, first of all, that all gaps in all surfaces or walls of your house where insulation is to be installed should be carefully sealed before that installing.

Dry-loose cellulose demands specific pneumatic equipment. Installation should have in count the time demanded by the material to attain the required settling-density-R-value. Installers should follow the manufacturer's demands.

Damp-sprayed cellulose installation requires a professional. Cellulose is applied into the open wall cavities, that should not be close before the cellulose acquires less than 25% water content (otherwise, walls could get moisture and mildew in the future).