Confused about all the different types and kinds of insulation for you home?
Another way to look at insulation
There are not really too many options to insulate a home. The old standby in insulating for many years has been fiberglass batts. Now there are other types of batts, like ground up blue jeans, but the fact remains that none of the performance building programs advocate using batt insulation anymore. The reason is it is difficult to fill the cavities correctly in odd shaped spots or where there are pipes and wires in them, and if there are voids or compressed batts in the wall it can greatly effect the performance of the insulation.
Fiberglass like the Blow In Blanket System (BIBS), is the best way to install fiberglass. And fiberglass like BIBS, which is blown in behind netting, is the most cost effective insulation. It is the only job tested insulation system, is R-4.23/inch, can’t settle, and is warranteed for the life of the building. Other insulation systems compare their insulation to fiberglass batts, but none compare their insulation to BIBS. When blown in it fills cavities very well. In existing walls, using the right fiberglass, it is as good as or better than, the cellulose that has been used for many years. And it has a higher R-value, and is made of sand and/or recycled glass by up to 70%.
Cellulose is made of ground up paper and cardboard with a fire retardant applied. It is about R-3.6/inch. In a flat ceiling we use cellulose all the time because it is more cost effective than fiberglass, enables a higher r-value over the top plate, and is better than loose fiberglass in terms of air infiltration. In a wall, cellulose has to be installed to such a high density to stop settling it is hard to apply the sheetrock. The density is not tested, so the installer has to be good to do it right. We just tested a new home with cellulose in the walls and there was already 2 spots where the IR camera said there were cold spots, which is usually due to settling. In an existing wall, cellulose has to be installed so tightly that the installer runs the risk of blowing the sheetrock off the wall. Cellulose has historically used a lot of recycled newsprint in it, but now there is not as much paper to be recycled as in the past so sometimes new paper is used in the insulation. This takes away from the argument that cellulose is 100% recycled.
Open cell foam, like Icynene, is a petroleum based foam that has an open cell structure that requires a vapor retarder like fiberglass and cellulose. R-value is 3.7/inch. It expands about 100 to 1 when blown in and then has to be shaved off to be flush with the studs. We have never seen an open cell foam job where the cavities did not have voids in it. Ideally, the installer should fill the whole cavity. Open cell foam is said to be great at sealing up a home. The cavities may be sealed, but what about the rest of the home? There are other ways to seal up cavities, and this is commonly done when using fiberglass and cellulose. The tightest homes in the world, those built to the Passive House standard, are insulated with fiberglass and cellulose. In our very cold climate, for the cost, the R-value, and the need for a vapor retarder, there is not much use for open cell foam, but this is just our opinion.
Closed cell foam is a petroleum based foam with a closed cell structure, which means it does not have to have a vapor retarder as long as it is thick enough. R-value varies between about R-6 to R-7, depending on the manufacturer and time. Closed cell foam off-gasses over time reducing the R-value. Find out what the final product is supposed to be. It is claimed that closed cell foam adds strength to the wall, and this is true. How much strength is the question. Homes have stood for a long time without it though. If you live in hurricane country, this would be a consideration. There are areas in a home where closed cell foam is good, like a band joist around a home. There are some other places in a home that might be best done with closed cell foam if you have limited space and need the most R-value. One consideration might be installing closed cell foam or open cell too. No one should be around when spraying the foam. OSHA is coming down hard on spray foam because of the health hazards. Installers use a supplied air hose to keep from breathing the gasses. Closed cell foam is a complex process. The chemicals have to be the right mix, the foam has to be the right temperature, and the surface getting the foam sprayed on it must be warm enough. And the rest of the air sealing also has to be done just like any home.
A consideration on insulation should be how long will it last? Fiberglass and cellulose have been around for over 50 years. Fiberglass is made out of sand, so how long will that last? The foams used in homes have been around only a few. Laboratories have done accelerated aging tests on foams but no one will say what it will be in 50 years. In fact, the foam industry came out with a long term thermal resistance study. So guess what long term means to them. 25 years? 50 years? In fact they use 15 years for their long term study! Foam also has other issues with fire and offgassing. Check out website foursevenfive.com.In building Passive Houses, which are super insulated and extremely tight, they commonly use fiberglass and cellulose and as little blown foam as possible. Part of the reason is a Passive House is built to last much longer than a typically built home. They use durable products and the whole structure is extemely well designed and modeled.
Another thing in the conversation these days with green building is how much embodied energy is in a product. This is a look at how much energy is used in making, transporting, and installing the material. A lot of people like cellulose because it is recycled materials used in the insulation so there is no energy used in making the material except the energy for grinding. The problem is, there is not the paper out there to be recycled anymore, like newsprint. Some of the cellulose companys are using new paper for cellulose insulation, because there is not the newsprint there used to be, so it is not all recycled material anymore. Fiberglass has differing amounts of recycled glass in it, Knauff Insulation has at least 60% in it. There is one plant in the US that is totally recycled glass. Foam insulation has a high amount of embodied energy in it. Again, check out foursevenfive.com. Call with questions.