There are many types of insulation in houses. In fact, with all these fiberglasses, batts, foam board, and so on, figuring out which is the best type of insulation can be quite overwhelming. That’s why we have created a simplified and structured approach to different types of insulation; supplemented by photos of each insulation type.
Namely, when choosing the best type of insulation, we are primarily looking at 3 things:
- Where do you want to add insulation? We talk about types of attic insulation, wall insulation (including basement wall insulation), ceiling insulation like basement ceiling insulation, exterior and interior insulation, and so on.
- Thermal performance or R-values. R-values depend on the thickness and type of insulation material. Example: Closed-cell spray foam R-value is 7 per inch. A fiberglass batt R-value is about 3.2 per inch. A 2.5-inch fiberglass batt has an R-value of 8.
- Application. Some types of insulation have to be installed during the building process (insulated concrete blocks, ICFs). Other types like insulation batts, rigid foam, loose-in insulation, or foamed-in-place insulation can be added later on as well.
Some insulation types are better for walls, others are better for ceilings, and the majority of the characteristics of insulation types come down to structural properties and R-values.
Insulation Types With Short Summaries
To get a full understanding of insulation materials, we are going to cover all 9 types of insulation used in houses. We are going to go type-by-type to get a good overview. Here is the shortlist of all the types of insulation used in residential properties:
- Insulation Type 1: Blanket insulation (batts and rolls). Most common insulation type, made out of fiberglass, used in walls, attics, floors. Typical R-value of about 3.2 per inch.
- Insulation Type 2: Concrete block insulation. Used in exterior and interior walls, insulation made out of polystyrene beads or rigid foam.
- Insulation Type 3: Rigid foam or foam board. Foam panels with superb thermal resistance. Very useful insulation type for basement walls and attics. Insulation materials include polyiso, polystyrene, and polyurethane. R-value of up to 8 per inch.
- Insulation Type 4: Insulating concrete forms. Connected foam boards inside poured concrete walls. One of the best types of insulation for walls; materials polyiso, polystyrene, and polyurethane. ICF walls can have, by themselves, an R-value of up to 20.
- Insulation Type 5: Loose-fill insulation, blown-in insulation. Insulation type that fits into any space; it is blown into any empty space in walls, attics, basements. Made out of cellulose, fiberglass, mineral wool. Typical R-value of about 2.4 per inch.
- Insulation Type 6: Radiant barriers. A specific type of radiant heat insulation, primarily used for attic insulation. Made out of aluminum foils that reflect heat and can reduce air conditioning costs by up to 10% in hot climates.
- Insulation Type 7: Rigid fiberglass boards. A special type of insulation for air ducts, made out of either fiberglass or mineral wool. High heat resistance is key here. Typical R-value of about 5.4 per inch.
- Insulation Type 8: Sprayed-foam insulation, foamed-in-place insulation. Typical closed-cell and open-cell insulation that can be sprayed, foam, injected or poured into attics, walls, under floors. Made out of polyurethane. Typical R-value of closed-cell spray foam is about 7 per inch. Typical R-value of open-cell spray foam is about 3.8 per inch.
- Insulation Type 9: Structural insulated panels. Prefabricated insulation panels for walls, ceilings, floor, and roofs. Foam boards are surrounded by oriented strand boards. Typical R-value can be well over 3 per inch.
In order to not get lost in all these insulation types, we are going to cover each type of insulation one by one. For each type, we will specify what it is (and include a photo just to illustrate what it looks like), what insulation materials are used, where you can install such insulation (wall, basement, attics, etc.), and what are typical R values.
With this in mind, let’s start with the first – and most commonly used – insulation type:
Insulation Type 1: Batts And Rolls Blanket Insulation
Batt insulation is one of the most widely used insulation types. It comes in batts or rolls that are pre-cut or can be cut in order to fill unfinished:
- Wall studs. Example: We use flame-resistant facing batts on basement walls.
- Attic rafters or trusses.
- Floor joists.
Basically, we are laying blankets of insulation on our unfinished walls, floors, and even ceilings (in attic or basements). Batt insulation is made out of different materials, including:
- Fiberglass. Fiberglass is the most commonly used material batts are made out of because it is flexible, widely available, and has high R-values.
- Cellulose; we talk about cellulose batt insulation.
- Mineral wool.
- Natural fibers.
- In limited cases, batts can be made out of plastic alternatives to fiberglass as well.
R-value of fiberglass batts is very high. You are looking at anywhere from R-2.9 to R-3.8 per inch of different types of batt insulation. High-density batts with compressed fiberglass can reach R-values as high as R-4.3.
That means that standard sizes of insulation batts have an extremely high overall R-value:
- 2×4 inch walls can hold batts with R-13 or even R-15 values.
- 2×6 inch walls can hold batts with R-19 or R-21 values.
We have batt insulation with or without facing. Facing is basically an aluminum foil layer (also kraft paper, or vinyl) that covers the batts. These facing can work as air barriers, radiant barriers (we cover radiant barriers in #6 type below), or vapor barriers.
Pretty much everybody is familiar with batt insulation. The key advantage of this type of insulation is that you can install it yourself (DIY insulation) and it’s pretty cheap compared to other types of insulation.
Insulation Type 2: Concrete Block Insulation
If you want to build a high R-value house insulation, you usually start with concrete block insulation. As with any concrete blocks, these ones are used to build the house foundation and walls. Construction-wise, however, you may determine that the cores of some concrete blocks don’t need to provide additional support.
In that case, you can use concrete blocks that are filled with insulation material; thereby raising the overall wall and foundation R-values during construction.
Material-wise, there are two types of these insulating concrete blocks:
- Polystyrene bead concrete blocks. In this type, polystyrene beads are incorporated into existing blocks. These are high R-value concrete blocks.
- Rigid foam rigid blocks. Here we use rigid foam inserts into various concrete blocks with empty cores. Be aware that the rigid foam is inserted into existing blocks; you usually can’t buy concrete blocks that already have rigid foam inserted.
- Concrete blocks with wood chips. Adding wood chips into cores increases the R-value of concrete blocks. These wood chip-filled blocks are stacked one on top of the other without the use of mortar. In construction terms, we call this ‘dry stacking’.
As with most concrete blocks, we have to be aware of the negative effects moisture and insects can have.
Of the precast high R-value blocks, you can either get:
- Autoclaved aerated concrete blocks (AAC). AAC are made out of high-silica sand. By volume, these concrete blocks are 80% air; extremely useful for insulation.
- Autoclaved cellular concrete blocks (ACC). ACC are made out of fly ash; a material that is used when burning coal.
As about 80% of the total volume of the blocks is air, you can imagine these concrete blocks are very light. They are quite easy to handle, you can shape them with a regular saw to fit the building requirements.
Overall, these concrete insulation blocks can have up to 10x higher R-value than regular concrete.
Insulation Type 3: Rigid Foam Or Foam Boards
Rigid foam boards are perfect to put on top of existing walls, ceilings, or floors. They are basically big thick panels with very high R-values that you can use pretty much anywhere, including:
- Outer walls as exterior wall sheathing. You can wrap foundation walls with foam boards to increase the R-value of foundation and basements.
- Inner walls as interior wall sheathing. Example: Rigid foam is one of the best types of insulation to insulate basement walls.
- Low-sloped ceilings.
- Attic inner walls. Attics are notoriously badly insulated. In order to increase the R-values, placing a foam board on the inner attic wall is a very effective solution.
These foam boards have an extremely high thermal resistance. Some of the high-density foams can reach an R-value of R-8 per inch. That is about twice as much as other comparable insulation type materials, like batts or foamed-in-place insulation. Example: If you were to use 5-inch rigid foam, you are already looking at the R-40 insulation value.
This is because of the insulation materials rigid foam is made out of. They include:
- Polyiso (also known as ISO or polyisocyanurate).
Insulation Type 4: Insulating Concrete Walls Forms (ICFs)
These are, in essence, poured concrete walls that can add up to R-20 insulation value to the walls themselves. Basically, standard walls don’t really provide that much insulation. That’s why these high thermal resistance concrete walls are used in order to prop up R-values and lower heating and air conditioning costs.
At its core, these wall forms are made out of several foam boards, placed inside the concrete wall forms. You connect these high R-value boards with plastic ties. There is a drawback to using these forms, however; you might imagine that they don’t have the same high structural properties as standard concrete blocks.
In order to increase the structural properties, steel rods are added into these forms before the concrete is poured over the. In such a way, we get:
- High R-value walls that decrease our heating and AC costs.
- Strong walls that can support our house.
Because the basis of these wall forms are foam boards, made out of polystyrene, polyiso, or other insulating materials, there is a danger that we will get high relative humidity there and insects. To prevent this from happening, some insulating concrete wall forms are pre-emptively treated with insecticides.
Insecticide treatment, coupled with waterproofing methods to keep the moisture out, are adequate measures that keep the wall forms from rooting from the inside out.
Insulation Type 5: Blown-In Insulation And Loose-Fill Insulation
The more insulation, the better is usually the rule. That’s why we build houses with insulation in mind. However, there are empty air pockets that can either stay empty (and provide no insulation) or be filled with insulation (providing additional R-values).
Here is where the loose-fill insulation type comes in. This type of insulation is basically blown-in (using a blowing machine) to fill any empty space and thereby utilize it for insulation.
Loose-fill insulation is incredibly versatile because you can use it pretty much anywhere:
- Attics. Blown-in insulation is the best insulation for attics because you usually have floor joists, empty nooks, and crannies into which you can easily fill insulation.
- Hard-to-reach spaces. You can’t use rigid foam boards in smaller spaces between walls, for example. Blown-in insulation comes in handy in these situations.
- Spaces with difficult shapes. Again, boards and batts need a horizontal surface area in order to be adequately installed. With loose-fill insulation, you can use it as a loose alternative to batts, for example.
Materials loose-fill insulation is made out of are pretty much any small particles with high thermal resistance like fiber (fiberglass, cellulose), foam, or mineral wool. Here are some examples of materials and their constitution:
- Cellulose loose-fill insulation. Much of the cellulose particles used in blown-in insulation are, in fact, made out of old newspapers.
- Fiberglass loose-fill insulation. For blown-in insulation, fiberglass containing anywhere from 40% to 60% of recycled glass is used.
- Mineral wool loose-fill insulation. This is rock wool or slag wool that is usually made out (mostly) of recycled wool.
- Polystyrene loose-fill insulation. Polystyrene is mainly used for rigid foam or boards. If you cut them down into small particles, you get a very effective blown-in insulation material.
Given there are many different types of blown-in insulation, the R-values also vary quite a lot. In general, we cite that loose-fill insulation has an R-value of R-2.2 to R-3.8. For the exact R-value, you should check the packaging of loose-fill insulation. Manufacturers are federally obligated to label the exact R-value of the insulation material on the packaging.
In the case of loose-fill insulation, this is especially important because the R-value per inch cannot be extrapolated with this type of insulation. Example: If you have a cellulose loose-fill insulation with an R-value of R-3 per inch, that doesn’t mean 4 inches thick cellulose insulation will have an R-value of R-12.
This is primarily because the more loose-fill insulation you use, the denser it gets (due to its own weight). That means that a 4-inch thick cellulose loose-fill will have an R-value greater than R-12 but you will also have to use more than 4 times as much material as you would for a 1-inch thick loose-fill.
We talk about initial thickness and settled thickness because R-value per inch is changing with the thickness of loose-fill insulation.
Insulation Type 6: Radiant Barrier Insulation
A radiant barrier is a specific type of insulation. We don’t have R-values here because we don’t use a radiant barrier to reduce heat conduction. We use a radiant barrier to significantly reduce radiant heat; that is heat generated by radiation (essentially, this is light).
Example: When you live a car in the sun, you will find that the car is hot. The energy that heated up your car is, primarily, solar radiation.
The purpose here is to reflect as much light (primarily sunlight) away from your home. That’s why we usually use aluminum foil over foam boards or kraft paper to radiate the heat away from your house.
These radiant barriers are best used where there is most sunlight, including:
- Attics. Attics are usually the main victims of radiant heating since they are located on top of a house and get a lot of sun exposure. A radiant barrier installed in the attic can reduce air conditioning costs by up to 5-10%.
- Unfinished walls. Sunshine on a wall with no radiant barrier can heat a house, even if you have R-40 insulation. If you were to use a radiant barrier, much of the radiation energy from the sun can be reflected away from your house.
- Garages. Garages usually have sub-par insulation and are exposed to the sun. The simple way to cool a garage in the summer is to use a radiant barrier in order to shield the attached garage from direct sun exposure.
It needs to be said that radiant barriers are mostly relevant for houses in hot climates. If you live in New York, you probably won’t reduce AC costs significantly enough to justify the cost of installing a radiant barrier.
If you live in Dallas, Miami, Or California, for example, and have an attic, a radiant barrier can be a very cost-effective way to cut the AC costs in the summer. If you have air cooling ducts running through the attic, the addition of a radiant barrier can reduce the AC costs by as much as 10% in hot climates.
Note: Installing a radiant barrier in cold climates isn’t financially viable. Yes, you may decrease AC costs by a couple of percent, but the radiation from the sun also warms your house in the winter. If you install a radiant barrier, you might have to pay more for heating than you save for air conditioning. That’s why thermal insulation is a better choice for colder climates.
Insulation Type 7: Rigid Fiber Board Insulation
This is a special HVAC insulation, mostly used for insulating ductwork. As you might imagine, the air in the ducts can be either cold (air conditioning in the summer) or hot (heating in the winter). Adequately insulating ductwork can significantly increase the effectiveness of heating/cooling.
Rigid fiber boards are made out of:
- Fiberglass. These are fiberglass rigid boards.
- Mineral wool. These are mineral wool rigid boards.
To insulate HVAC ductworks, you use prefabricated boards. These have thicknesses from 1 inch to about 2.5 inches. Basically, you have to wrap the exterior duct walls with rigid fiber boards. Given that a typical R-value of rigid fiber boards is about R-5.4 per inch of thickness, the thickest 2.5-inch board has can have an R-value of R-13.5.
These boards are mounted with weld pins and secured with clips or washers. On top of the boards, you can add insulating cement, waterproof mastic, or other materials for additional insulation.
As we have said, this is a specialized type of insulation that gets overlooked quite easily. Nonetheless, pretty much everybody understands that is useful to keep ductwork insulated due to the high difference in temperature between air ducts and the surrounding environment.
Insulation Type 8: Sprayed-Foam Insulation Or Foamed-In-Place Insulation
Sprayed foam is one of the most useful insulation types. It comes from small spray cans to big construction-size foamed-in-place machines. Basically, these spray foams consist of liquid foam that expands and fills in the gaps in walls, ceilings, basements, attics, you name it. It is incredibly versatile and can be used in pretty much any part of the construction phase, and even after that.
Smaller spray cans come especially handy when you have to do small DIY jobs that do a significant positive impact. These include:
- Using spray foam around doors. The area around the doors conducts heat very well. That’s why it needs to be insulated very well.
- Spraying around windows. Windows are in many cases the part of the house where we use the most heat.
- Insulating vents with spray foam.
In bigger jobs, the sprayed foam can be blown into large walls, onto attic surfaces, and on top of floors. If you want to insulate an attic or basement, the foamed-in-place insulation is the quickest and one of the most efficient ways to do it.
If you have ever used a sprayed foam, you know that it expands quickly, and it’s easy to cut, trim, or even paint over.
There are two main types of foamed-in-place insulation foam, namely:
- Open-cell spray foams. These are simple polyurethane foams, filled with air. They are of lower density and have lower R-values. A typical open-cell spray foam will have an R-value of R-3.7 per inch of thickness. Open-cell spray is cheaper than closed-cell spray.
- Closed-cell spray foams. These are also made out of polyurethane foams. They consist of high-density cells; these cells are closed and contain a gas that helps them to expand into any space surrounding the spray foam. Because closed cells are more densely packed, they have a higher R-value than open-cell foams. Typically, closed-cell spray foam will have an R-value of at least R-4 per inch of thickness but you can also find high R-value closed-cell foam sprays with up to R-6.5 per inch insulation value. They are more expensive than open-cell foams, however.
Which one is better: Open-cell foam or closed-cell foam?
When you compare open-cell foam vs closed-cell foam, you will likely have to compare:
- R-values. Closed cells have about 50% higher R-value than open cells.
- Price. Open cells can be anywhere from 10% to 70% cheaper than closed cells.
A key advantage of closed-cell foam compared to open-cell foam is water resistance. That’s why if you are trying to insulate spaces that are usually moist like basements, you are always recommended to choose closed-cell spray foam instead of open-cell spray foam.
Because it can be sprayed in place pretty much anywhere and has a very high R-value per inch, this type of insulation is especially useful in colder climates. For installation, you can do DIY for smaller jobs. For bigger jobs, you will need insulation professionals.
Insulation Type 9: Structural Insulated Panels (SIPs)
Structural insulated panels are used during the construction phase. They are usually shipped from the factory to the construction site; they are prefabricated. Basically, SIPs are insulation-focused building materials that can reduce heating and AC costs by as much as 14%, according to the US Department Of Energy.
Using SIPs, you can build pretty much any part of the house, including:
In essence, SIPs consist of layers of foam boards squeezed together by an oriented strand board on either side. You can easily get SIPs with facing on the interior side, exterior side, or both. Foam boards can be made out of polystyrene or polyiso foam.
Obviously, SIPs have a very high R-value for building materials. A typical R-value per inch for structural insulated panels is about R-3 per inch. You would use 4-inch or 8-inch boards; with a total insulation R-value of R-12 or R-24, respectively.
This is not its only useful quality. Namely, for an insulation type, structural insulated panels:
- Have a very high strength-to-weight ratio. Hence the word “structural” is justifiably used here. If you compare structural insulation panels to concrete block insulation, you will see that you don’t need steel reinforcements here due to an amply high strength-to-weight ratio.
- Provide for a quieter home. The SIPs are very airtight, and thereby provide sound insulation as well.
To prevent fires, SIPs are also covered with fire-retardant materials.
Summary Of Insulation Types
All in all, we have a clear overview of all types of insulation used in home construction. Most of these types will require professional installation. However, some smaller jobs like sprayed-foam insulation you can do yourself.
This is an overview article. We have looked into specific problems and questions about insulation. If you just look around a bit, you might find answers to your insulation questions. If you don’t, you can use the comment section below and we will try to help you out.