Insulation is the material that regulates the temperature within your house, often found inside attics, walls, garages, unfinished basements and crawl spaces. There are several different types of insulation available, including fiberglass batts and rolls, blown-in cellulose or spray foam, all with varying R-values and different strengths. There is also TAP insulation, which is famous for being “pest control” insulation. While TAP is able to repel some pests, they are not a broadly effective pest solution. You might be wondering which type of insulation is the “best” type. The truth is, there is no “best” type of insulation, only the best type for you.
Insulation Batts and Rolls
The most recognizable type of insulation is batted insulation also known as blanket insulation, rolls of pink or yellow fiberglass or mineral wool, often laid down in thick layers inside walls and attics. Batts and rolls are great for covering large areas all at once, and great for flat areas that are easy to access. Batt insulation is also the most cost effective type of insulation, often being cheaper than blown-in or spray foam insulation.
The two main types of batt insulation are fiberglass and mineral wool. Mineral wool is the denser, heavier material, rigid and used for exterior walls, basements and crawl spaces. Fiberglass insulation is lighter, less dense, more flexible and used more in interior spaces, like in between walls and inside attics and garages.
However, the most important difference between these two comes with their R-value. R-value is the measurement of an insulation’s resistance to heat. The higher the R-value per inch, the more effective the insulation is. The cost of the insulation will go up as the R-value per inch goes up. Fiberglass insulation has an R-value of about 2.6-2.8, whereas mineral wool has an R-value of 3.5-3.8.
Cellulose “Blown-In” Insulation
Another type of insulation available on the market is cellulose insulation, often known as blown-in insulation or loose fill insulation. Cellulose insulation is a thick, clumped material made out of recycled paper products, often recycled newspapers. If you are worrying that a paper insulation material would burn easily, cellulose insulation has you covered. Cellulose insulation is treated with flame retardant chemicals like borate, which means it can actually control the spread of fire.
The main advantage of this type of insulation is its ability to be “blown-in”, which means loose chunks of it are blown over or into the area that needs covering. If your walls or attics have lots of small, hard to reach spaces that batted insulation just can’t fit into, or awkward, clunky structures that the insulation needs to fit around, then blown-in insulation is perfect. Blown in insulation allows you to insulate areas that blanket insulation can’t reach, protecting you against the outside air and giving your home a more complete insulation barrier. Sometimes, your existing insulation is fine, but has settled over time, which means you need more insulation applied. Blown-in insulation is one of the very few types of insulation where you can apply more insulation on top of the existing stuff, instead of having to strip the old insulation out and replace it with newer material.
Another advantage of blown-in insulation is how eco-friendly it is, as cellulose insulation is made of primarily recycled newspaper. The R-value of blown-in cellulose insulation is a bit higher than fiberglass batts, with an R-value of about 3.5-3.8. According to insulation expert Tim Jordan, “you can use less cellulose insulation to equal a higher R-value.”
Spray Foam Insulation
Spray foam insulation is a type of foam insulation that is sprayed on walls and inside cavities that hardens quickly and provides a solid thermal and air barrier that can seal any air leaks that may be in your home.
The biggest advantage of spray foam insulation is that it can be sprayed on surfaces that batts and blown-in insulation just can’t cover. Spray foam can seal any cracks, nooks and crannies where it is applied, creating an air seal that keeps all the outside air out of your home. This air seal can improve your home’s energy efficiency, and lower your reliance on your furnace/air conditioning system during the harsher temperatures of winter/summer. There are two distinct types of spray foam: open-celled and closed-celled.
The foam in spray foam is made up of bubbles called “cells’. Open-cell insulation leaves these cells open and not totally sealed off, which makes the material softer. This material is less dense and more flexible, and the number one advantage of open cell spray foam is that it can expand to fill any nook or cranny in the area you are applying it to, ensuring you have a total air seal barrier in your home.
The cells in closed cell insulation are pressed together tightly and completely closed, creating a more rigid material. Closed cell spray foam also has a higher R-value than open cell. While open cell foam has an insulation value of about 3.5-3.8, closed cell foam can have an R-value of up to 6.5-7. Closed cell foam totally rejects water and vapor, preventing any from passing through it. Closed cell foam is preferable in areas prone to flooding, and FEMA has even recognized it as flood-resistant. Closed-cell foam is still able to create a total air seal barrier, but with closed-cell foam, you need to directly apply the material to any area that needs to be covered in order to create the air seal. For open-cell foam, you can use much less material and the foam will expand on its own to fill the cracks, nooks and crannies.
The Myth about TAP Insulation
A very common thing you might be sold is a special brand of insulation that “kills pests”, commonly known as TAP (Thermal, Acoustic, Pest) insulation. While a cure-all pest-killing insulation sounds nice, the unfortunate reality is that it often just isn’t true. The chemical that kills pests in TAP insulation is borate, a fire retardant. While borate is an effective treatment for silverfish, it is not broadly effective against all kinds of pests. Borate has no effect on rodents like mice, rats and squirrels, and some pests like roaches can build up an immunity to the borate that the insulation is treated with. While TAP insulation isn’t a bad material, it simply is not an effective form of pest management.
What Type of Insulation is Best?
So, after reading all of this, you probably have one question in your mind: which type of insulation is the BEST? Batts and rolls of fiberglass or mineral wool insulation have a decent r-value and are very cost-effective, but they can’t fill hard-to-reach places. Blown-in cellulose insulation can fit into hard-to-reach places and be applied over existing insulation with a higher r-value than batts and rolls. Spray foam insulation can create an air seal barrier that doesn’t allow ANY air, vapor or water in, fully protecting your house with the highest r-value, but also tends to be more expensive than blown-in or batts. There isn’t one best type, instead the specific type of insulation that fits YOUR individual needs and YOUR home is the “best” type of insulation.