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Insulation Types | All You Need to Know

There is a lot to consider when it comes to insulation, such as which is better for a certain area, which is a better insulator, what the cost is, and what you should keep in mind about the many different options.

You can and should ask these questions, but it can get a little confusing to keep it all straight. So, I have compiled the following summaries of the various insulation options to help you find the necessary information and decide.


The variety of insulation available is fiberglass, cellulose, natural fiber, plastic fiber, mineral wool, spray foam, and foam board. These have different R-values, prices, and strengths and weaknesses. Depending on the form the insulators can take, they are also applicable in different areas.

Fiberglass Insulation

CompositionFiberglass insulation consists of individual long, thin glass fibers.

These glass fibers are created from synthetic and raw materials like stones, ash, and silicon variants.

It is a common form of insulation known for its longevity (±100 years).
AppearanceThis insulation has a woolen appearance.

The glass strands are packed into batts, rolls, and boards, or the fibers look like wads of cotton for blown-in application.

Commonly, fiberglass insulation is also pink, green, or blue. However, other colors, like yellow, are also possible, depending on the manufacturer.
Forms and TypesFiberglass insulation is available in many forms:
– Batts
– Rolls
– Boards
– Loose fill
R-ValueFiberglass insulation R-value range:
– Batts = R3.1-R3.4
– Rolls = R3.1-R3.4
– Blown-in = R2.2-R2.7
Average cost (per square foot)Excluding labor, fiberglass insulation will cost approximately:
– Batts = $0.64-$1.20
– Blown-in = $0.50-$1.00
UseFiberglass insulation can be used for ceilings, attic spaces, floors, walls, and around pipes and ducts.

Batts are used between wall studs, and rolls and boards are used from between ceiling joists and in walls.

The blown-in option is great for odd and hard-to-reach spaces, like in the attic or around piping.  
Toxic potentialFiberglass is an irritant, so you need to use protective gear.

The thin strands can easily break, scratch, and stab your skin, resulting in rashes, dermatitis, and even blisters.

These fibers can also be inhaled and get into your eyes, where they can cause harm and irritation.
Top advantageFiberglass is the most cost-effective insulation. Not only is the material low-cost to buy, but it is also easy to install yourself, so you can skip the labor charges.
Top disadvantageThis insulation is not a vapor barrier, meaning you need to make other provisions on top of the insulation to keep moisture out of your home.
Fiberglass batt insulation placed in the attic

For more information, look at Fiberglass Insulation | Complete Guide

Cellulose Insulation

CompositionCellulose insulation is a wood-based fiber material. Most of the insulation is made from paper products that are recycled and treated.

It is treated to be less flammable and prevent pests from damaging it.

Although not as long-lasting as other insulations, this material can last between 20 and 30 years.
AppearanceCellulose insulation looks like fine shreds of paper. Its texture is almost wooly and fluffy.

The recycled paper gives the insulation a grey color, which comes from the ink traces on the paper products.
Forms and TypesYou will traditionally find cellulose insulation in two forms:
– Loose-fill
– Dense-packed

However, more recently, batted cellulose has also become more common.
R-ValueTypical R-value range for cellulose insulation: R3.2-R3.8
Average cost (per square foot)Loose-fill cellulose for blown-in insulation will cost approximately $0.80-$1.20.
UseCellulose insulation in its loose-fill form can be found in unfinished attic spaces.

The dense-packed version is used to insulate ceilings and wall cavities.

Batted cellulose is used for insulating walls.
Toxic potentialCellulose is treated with several chemicals (like borax, boric acid, and ammonium sulfate) to make it fire-resistant, which can be released as the material breaks down with age, after 20-30 years.

If you have sensitivities, there are some trace substances (irritants) in cellulose, including the ink from the recycled paper that you should be aware of.
Top advantageCellulose insulation is paper; as such, it is treated for fire retardation. The result is that the material is very fire-resistant. Additionally, it is unpalatable for pests.
Top disadvantageThe primary disadvantage of cellulose is that it is not water-resistant and takes a long time to dry out. It is, therefore, susceptible to mold growth.

For more information, look at Cellulose Insulation | Complete Guide

Man wearing full PPE while filling up the attic with cellulose insulation

Natural Fiber Insulation

CompositionAs indicated by the name, this insulation is made from natural materials from animals and plants, like wool and cotton.
AppearanceCotton: a bluish-gray, densely compacted cotton fluff and pieces of material.

Wool: a fluffy material expected from a woolen product in white, grey, or brown.

Straw: whether baled or boarded, it still looks like straw, both in texture and gold/yellow color.

Cork: chunks of cork compressed together.

Cellulose: a light golden-brown cottony and fluffy material.

Hemp: a brown or grayish fluffy, woolen-looking material.

Wood fiber: looks like golden-brownish straw-like splinters or compacted sawdust.
Forms and TypesThe materials that the insulation is available in are as follows:
– Sheep’s wool
– Cotton
– Cellulose
– Wood fibers
– Straw
– Cork
– Hemp

This type of insulation comes in several forms:
– Bales
– Batts
– Boards
– Loose-fill
R-ValueApproximate R-value per inch or range of values for different natural fiber insulation:
– Sheep’s wool = R3.2-R3.8
– Cotton = R3.8
– Straw = R2.0
– Cellulose = R3.2-3.8
– Hemp = R3.7
– Cork = R3.7
Average cost (per square foot)The approximate pricing range for the different types:
– Cotton = $0.76-$4.28
– Wool = $1.50-$2.81
– Cellulose = $1.20-$2.50
– Cork = $0.20-$12
– Wood fiber = $4.25-$6.75
– Hemp = $3.00
– Straw = $3.60
UseThanks to the range of materials available in natural fiber insulation, you are likely to find a form that fits your need.

You can get bales, boards, batts, and loose-fill. This means that you can use it for floors, walls, roofs/ceilings, and smaller/non-uniform cavities.
Toxic potentialThere are some risks of allergies if you happen to be sensitive to that natural material.  

There is little other concern since natural fibers are generally safer than synthetic materials.
Top advantageNatural fiber insulation, in addition to the insulating qualities, also offers a level of soundproofing. This means it is helping to shield your home from noisy neighbors and street sounds.
Top disadvantageThe drawback of using natural materials is that they are likely to degrade faster than synthetic materials. 

For more information, look at Natural Fiber Insulation | Complete Guide

Man wearing gloves while cutting a natural fiber insulation

Plastic Fiber Insulation

CompositionPlastic fiber insulation is made from plastics. Recycled materials are used to create the insulation, like bottles.

This insulation can last a good 60-75 years, provided it is maintained and does not get damaged.
AppearanceDespite the name “plastic”, this insulation actually looks like a white or yellow sheet of cotton, or it can look like shaving cream. It all depends on which form you are using.
Forms and TypesThere are three main types of plastic fiber insulation:
– Polystyrene
– Polyurethane
– Polyisocyanurate

Within the range of these types, you will find plastic fiber insulation in the form of:
– Blanket sheets
– Rolls
– Spray foam
R-ValuePlastic fiber insulation’s R-value per inch typically ranges between R4 and R7.2.
Average cost (per square foot)The cost depends on what type your insulation comes in:
– Polystyrene = $0.30-$0.45
– Polyurethane (usually spray) = $0.44-$1.50
– Polyisocyanurate = $0.70
UsePlastic fiber insulation can be used around pipes, in ceilings, attics, walls, and almost anywhere. You just need to select the form that fits where you want to use it.
Toxic potentialPlastic fiber insulation, particularly spray foam, can produce volatile organic compounds (VOCs) and other chemicals. This is usually only a risk during the insulation process.

This is also why it is recommended that professionals are consulted and hired for the job.
Top advantagePlastic fiber insulation is highly effective, meaning that thinner layers achieve higher R-values compared to other insulators.
Top disadvantageUnfortunately, the performance and low maintenance associated with plastic fiber insulation comes at a cost. Quite literally—it is one of the most expensive types of insulation.

For more information, look at Plastic Fiber Insulation | Complete Guide

Orange plastic insulation roll

Mineral Wool Insulation

CompositionMineral wool insulation is a fiber insulation made from natural materials.

It is either called rock wool and is made from stone, or it is called slag wool and is made from the waste products of iron ore.

It typically lasts 30-80 years, depending on the type of mineral wool used and the conditions where it is installed. 
AppearanceMineral wool has brown, almost sponge-like appearance and is compressed into shape.
Forms and TypesMineral wool insulation comes in two types:
– Rock wool
– Slag wool  

You can get mineral wool insulation in the following forms:
– Batts
– Rolls
R-ValueR-value range for mineral wool insulation: R2.8-R4.3 per inch.
Average cost (per square foot)Typically, mineral wool insulation will cost between $1.40 and $2.10.
UseMineral wool is an insulator that can be used just about anywhere you need insulation, including attics, ceilings, floors, and walls.
Toxic potentialProtective gear is important for working with mineral wool insulation as it is harmful to inhale fibers and binders (in higher quantities and concentrations).
Top advantageMineral wool insulation is moisture-resistant. This helps prevent mold problems with the insulation. It also helps to maintain the effectiveness of the insulating material since water impacts how heat is contained and transferred.
Top disadvantageThe most significant drawback of mineral wool is that it is dangerous to work with. The skin, eyes, and respiratory system must be protected from the fibers and the carcinogenic glue used on the insulation.

For more information, look at Mineral Wool Insulation | Complete Guide

Man wearing PPE while installing mineral wool insulation

Spray Foam Insulation

CompositionSpray foam insulation is made from a type of plastic called polyurethane (the most common type) or a combination of polyol resin and isocyanate (a salt).

Spray foam is available in different densities and structure rigidity that relate to R-value.  

Spray foam is very durable and long-lasting (80-100 years).
AppearanceSpray foam insulation is white and looks like shaving cream. As it dries, it takes on an even fluffier appearance and hardens.

It comes as a liquid and is applied using a spray gun. A chemical reaction occurs during this spraying, which is how it comes out as a foam.
Forms and TypesSpray foam insulation comes in three variations:
– High-density
– Medium-density
– Low-density

It also comes in two forms that refer to the structure of the foam:
– Open-cell
– Closed-cell
R-ValueOpen cell spray foam: R3.5 per inch.

Closed cell spray foam: R6 per inch.
Average cost (per square foot)Open cell spray foam: $0.44-$0.65.

Closed cell spray foam: $1.00-$1.50.
UseSpray foam is incredibly versatile, durable, and effective. This means that it can be used in any place you need insulation.
Toxic potentialProtective gear is important to protect your respiratory system and skin.

Before the foam cures and hardens, there are some fumes emitted from the chemical reaction that takes place. These should not be breathed in.

The foam is can also cause irritation if it touches the skin.
Top advantageSpray foam insulation creates an airtight seal. This is because it expands and will fill the cavity and all the crevices in the space as it does. This makes it more effective as an insulator.
Top disadvantageIt is crucial to ensure there is enough foam to reach all the spaces during expansion; otherwise, it is not as effective. Especially if water gets into those gaps as this damages the insulation.

For more information, look at Spray Foam Insulation | Complete Guide

Man wearing white full PPE while spraying foam insulation on the attic

Foam Board Insulation

CompositionFoam board insulation is a very long-lasting (100+ years) insulator that is manufactured using variations of plastic that form a closed cell (rigid) board.
AppearanceFoam board insulation is a rigid, solid sheet with a tightly packed sponge-like appearance. Some also have laminated sides.

It is generally pink, blue, or white.
Forms and TypesThere are three types of foam board insulation:
– Polyurethane
– Polystyrene
– Polyisocyanurate

This insulation only comes in sheet form as its rigid nature requires it to be a whole piece (not loose fill), but it is also too structured to roll up.
R-ValueR-values for foam board per inch:
– Expanded polystyrene = R3.6-R4.0.
– Extruded polystyrene = R4.5-R5.0.
– Polyurethane = R7.0-R8.0.
– Polyisocyanurate = R7.0-R8.0.
Average cost (per square foot)The approximate costs for foam board insulation are:
– Expanded polystyrene = $0.31.
– Extruded polystyrene = $0.47.
– Polyurethane = $0.60.
– Polyisocyanurate = $0.60.
UseFoam board insulation can be used in all the places where sheet insulation can be installed, including the roof, foundation walls, and wall cavities.
Toxic potentialFoam boards can still contain toxic flame-retardant chemicals, which are used to treat the insulation.

These foam boards are also associated with helpful insecticides, which can negatively impact health.
Top advantageFoam board insulation is durable and has a higher R-value than some other insulation types. This means that it works well and is long-lasting.  
Top disadvantageThe R-value can decrease over time as the insulation deteriorates and gases escape from the polyisocyanurate and polyurethane boards.

For more information, look at Foam Board Insulation | Complete Guide

Stacked foam board insulation

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