5 Most Common Thermal Insulation Materials

There are plenty of cheap and common insulation materials available on the market today. Many of these have been around for quite some time. Each of these insulations have their own ups and downs. As a result, when deciding which insulation material you should use, you should be sure to be aware of which material would work the best in your situation. We have considered differences like R-value, price, environmental impact, flammability, sound insulation and other factors below. Here are the 5 most common types of insulation materials:

The table below scrolls horizontally to display additional columns of data.

Insulation MaterialPrice/Sq Ft.R-Value/InchGreen? (Environmentally Friendly)Flammable?Notes:
Fibreglass$R-3.1YesNoDoes not absorb water.
Mineral Wool$$R-3.1YesNoDoes not melt or support combustion.
Cellulose$$R-3.7YesYesContains the highest amount of recycled content.
Polyurethane Foam$$$R-6.3NoYesMakes a great sound insulator.
Polystyrene (EPS)$R-4NoYesDifficult to use around imperfections, can be come costly.


1. Fiberglass

pink fiberglass insulation

Fiberglass Insulation.

Fiberglass is the most common insulation used in modern times. Because of how it is made, by effectively weaving fine strands of glass into an insulation material, fiberglass is able to minimize heat transfer. The main downside of fiberglass is the danger of handling it. Since fiberglass is made out of finely woven silicon, glass powder and tiny shards of glass are formed. These can cause damage to the eyes, lungs, and even skin if the proper safety equipment isn’t worn. Nevertheless, when the proper safety equipment is used, fiberglass installation can be performed without incident.

Fiberglass is an excellent non-flammable insulation material, with R-values ranging from R-2.9 to R-3.8 per inch. If you are seeking a cheap insulation this is definitely the way to go, though installing it requires safety precautions. Be sure to use eye protection, masks, and gloves when handling this product.

2. Mineral Wool

mineral wool

Mineral Wool.

Mineral wool actually refers to several different types of insulation. First, it may refer to glass wool which is fiberglass manufactured from recycled glass. Second, it may refer to rock wool which is a type of insulation made from basalt. Finally, it may refer to slag wool which is produced from the slag from steel mills. The majority of mineral wool in the United States is actually slag wool.

Mineral wool can be purchased in batts or as a loose material. Most mineral wool does not have additives to make it fire resistant, making it poor for use in situation where extreme heat is present. However, it is not combustable. When used in conjunction with other, more fire resistant forms of insulation, mineral wool can definitely be an effective way of insulating large areas. Mineral wool has an R-value ranging from R-2.8 to R-3.5.

3. Cellulose


Cellulose Insulation Material.

Cellulose insulation is perhaps one of the most eco-friendly forms of insulation. Cellulose is made from recycled cardboard, paper, and other similar materials and comes in loose form. Cellulose has an R-value between R-3.1 and R-3.7. Some recent studies on cellulose have shown that it might be an excellent product for use in minimizing fire damage. Because of the compactness of the material, cellulose contains next to no oxygen within it. Without oxygen within the material, this helps to minimize the amount of damage that a fire can cause.

So not only is cellulose perhaps one of the most eco-friendly forms of insulation, but it is also one of the most fire resistant forms of insulation. However, there are certain downsides to this material as well, such as the allergies that some people may have to newspaper dust. Also, finding individuals skilled in using this type of insulation is relatively hard compared to, say, fiberglass. Still, cellulose is a cheap and effective means of insulating.

4. Polyurethane Foam

polyurethane insulation spray application

Polyurethane Insulation.

While not the most abundant of insulations, polyurethane foams are an excellent form of insulation. Nowadays, polyurethane foams use non-chlorofluorocarbon (CFC) gas for use as a blowing agent. This helps to decrease the amount of damage to the ozone layer. They are relatively light, weighing approximately two pounds per cubic foot (2 lb/ft^3). They have an R-value of approximately R-6.3 per inch of thickness. There are also low density foams that can be sprayed into areas that have no insulation. These types of polyurethane insulation tend to have approximately R-3.6 rating per inch of thickness. Another advantage of this type of insulation is that it is fire resistant.

5. Polystyrene

polystyrene material

Polystyrene (Styrofoam).

Polystyrene is a waterproof thermoplastic foam which is an excellent sound and temperature insulation material. It comes in two types, expanded (EPS) and extruded (XEPS) also known as Styrofoam. The two types differ in performance ratings and cost. The more costly XEPS has a R-value of R-5.5 while EPS is R-4. Polystyrene insulation has a uniquely smooth surface which no other type of insulation possesses.

Typically the foam is created or cut into blocks, ideal for wall insulation. The foam is flammable and needs to be coated in a fireproofing chemical called Hexabromocyclododecane (HBCD). HBCD has been brought under fire recently for health and environmental risks associated with its use.

Other Common Insulation Materials

Although the items listed above are the most common insulation materials, they are not the only ones used. Recently, materials like aerogel (used by NASA for the construction of heat resistant tiles, capable of withstanding heat up to approximately 2000 degrees Fahrenheit with little or no heat transfer), have become affordable and available.  One in particular is Pyrogel XT. Pyrogel is one of the most efficient industrial insulations in the world. Its required thicknesses are 50% – 80% less than other insulation materials. Although a little more expensive than some of the other insulation materials, Pyrogel is being used more and more for specific applications.



Other insulation materials not mentioned are natural fibers such as hemp, sheep’s wool, cotton, and straw. Polyisocyanurate, similar to polyurethane, is a closed cell thermoset plastic with a high R-value making it a popular choice as an insulator as well. Some health hazardous materials that were used in the past as insulation and are now outlawed, unavailable, or uncommonly used are vermiculite, perlite, and urea-formaldehyde. These materials have reputations for containing formaldehyde or asbestos, which has essentially removed them from the list of commonly used insulation materials. .

There are many forms of insulation available, each with their own set of properties. Only by researching each kind thoroughly can you discover which will be the right kind for your particular needs. As a quick overview:

  • Aerogel is more expensive, but definitely the best type of insulation.
  • Fiberglass is cheap, but requires careful handling.
  • Mineral wool is effective, but not fire resistant.
  • Cellulose is fire resistant, eco-friendly, and effective, but hard to apply.
  • Polyurethane is an all around good insulation product, though not particularly eco-friendly.
  • Polystyrene is a diverse insulation material, but its safety is debated.

Related Posts:

The Difference Between Hot And Cold Insulation Materials

Insulation Ratings: Calculating R Factor, K Factor & C Factor



About Thermaxx Jackets

Thermaxx Jackets was founded over 25 years ago with a single purpose: to save energy when traditional stay-in-place insulation is not practical. Combining expertise in heat loss, wireless monitoring, insulation design, and several other disciplines, we’ve become the #1 provider of removable insulation jackets and covers.
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97 Responses to 5 Most Common Thermal Insulation Materials

  1. Inayat Durrani says:

    I have a study project for thermal insulation solution. I have a red hot exhaust pipe with temperature of hot gases of about 800 degree celcius. The space available above it is 13mm and a motor above it have temperature bearing capacity of 50 degreee celcius. I want a its thermal insulation so that temperature reduces to 50 degree celcius so that motor operates efficiently.

    • haresh vashi says:

      Go with two layer of ceramic blanket of 6mm to 8mm thickness .make sure that the first layer joint is overlapped by the other layer . this will surly work

  2. Brian Bannon says:

    13mm is a very small space to insulate. I do not know of any insulation, 13mm thick, that will reduce the temperatures to your requirement. You may want to investigate reflective shields.

  3. lorenzo says:

    a layer of aerogel blanket should work. the best would have to be a solid layer of aerogel cast on the exhaust pipe or engine, but a blanked should do.
    you can find 8 mm thick blankets online and maybe squeeze in 2 layers in your 13 mm space.
    hope this helps

  4. carol gunsallus says:

    bales of hay or rolls of hay which is best anyone out there with coments ????

  5. carol gunsallus says:

    we r trying to insulate a school bus …quickly… thanks

    • haresh vashi says:

      for insulating a school bus. puff panel of 25mm thickness is the best choice and where there is an uneven places just inject the puff

  6. Typical insulations for piping systems will not be a good choice for a school bus due to fiberglass fibers making children itch! It would seem that a 1″ thick Styrofoam type of insulation (found at Lowes/Home dept) would work nicely. The panels can be easily cut and glued to the structure.

  7. Aliyah says:

    What is the best thermal insulator out of polyestyrene, fibre glass and bubble wrap???
    And why?

  8. Will jones says:

    What are you insulating? What temperatures, interior or exterior application

  9. thomas says:

    i need help for providing a heat insulation for 500 degree C.which insulation should i prefer
    provided the rate of material should not be expensive

    • haresh vashi says:

      There are two options.
      1. either go with two layer of L R B .50mm thick & 150 kg/m3 density. make sure that the first layer joint is properly overlapped by the other layer. Cover the entire insulation with aluminium sheet to ensure weather proof.

      2. Cerewool blanket of 25mm & 96 kg/m3 will also do Again it should be double layer and joints as above

    • haresh vashi says:

      There are two options.
      1. either go with two layer of L R B .50mm thick & 150 kg/m3 density. make sure that the first layer joint is properly overlapped by the other layer. Cover the entire insulation with aluminium sheet to ensure weather proof.

      2. Cerewool blanket of 25mm & 96 kg/m3 will also do Again it should be double layer and joints as above

      LRB 50mm x 150kg/m3 = 350=00 per M2
      cerewool 25mm x 96 kg/m3 =500=00 m2
      Aluminium sheet of 24 swg = 400=00 m2

  10. Will Jones says:

    There are several choices. If you are simply insulation a component and not utilizing a removable insulation jacket then type E needled fiberglass, Pyrogel XT-E and Silica would all do a good job. To get a touch temperature below 60C you would need appox. 90mm (3.5″) of type E needled fiberglass . If Pryogel XT is used then 50mm (2″) would lower the touch temperature to below 60 C. Cost is relative.

  11. albertus ng says:

    I’m designing a fiberglass box delivery (motorcycle delivery) for frozen processed food. The fiberglass itself is good for thermal insulation. However since it was originally designed for container instead of thermal insulation, I decided to add an additional heat insulation, inside. What is the most suitable materials, considering thinner is better (as to safe the inner space)?

    • Rubber insulation should do a great job!

    • haresh vashi says:

      There is a thermal insulation paint .just paint with double coat. this will do.

      Another option is if you can vacumize between the two layer of your container that is also the best method. This helps by the way ,non movement of air in your container.

  12. shivam dwivedi says:

    I need to know of any insulation that can be applied on a pipe of dia 1.4 meters transfering hot gases with temperature ranging from 800 ‘ celcius with a length of 16 meters.
    my objective is to stop surface heat loses and to reduce temperature drop due to same it.

    • Shivam,
      First thing is an insulation which will perform at 800 C, Ceramic insulation blankets will do the job. Next, we need to design for a “touch temperature”. A Pipe at 1.4 meters diameter has a tremendous heat loss. Using 3EPlus to calculate the BTU loss and insulation thickness, 24cm of insulation is required to get the surface temperature below 60 C. The BTU per hour savings is 254583 BTU/FT ( 30.48 cm) of pipe. This is a significant savings.

  13. Jeremy says:

    Looking to cool off my garage very cheap… thoughts on using recycled paper egg cartons?

    • Recycled Egg cartons is an excellent idea. The design by nature has lots of dead air space, it is light weight and easily handled. If the garage has no ceiling, rather exposed rafters I would put a small exhaust fan at the peak at the exterior wall and get the really hot air out of the space. That should do it!!

  14. Shivam,
    First thing is an insulation which will perform at 800 C, Ceramic insulation blankets will do the job. Next, we need to design for a “touch temperature”. A Pipe at 1.4 meters diameter has a tremendous heat loss. Using 3EPlus to calculate the BTU loss and insulation thickness, 24cm of insulation is required to get the surface temperature below 60 C. The BTU per hour savings is 254583 BTU/FT ( 30.48 cm) of pipe. This is a significant savings.

  15. biodun says:

    Am work on developing a lagging material as a project…can someone tell me some of the standard methods for testing insulating materials…that I can I use to compare the thermal conductivity of the lagging material..

    • Brian Bannon says:

      Most commercial insulation manufactures can provide you with the K factor. You can also contact NIA…the National Insulation Association

  16. Nilesh says:

    I want to use thermal insulation in thermal mug. which material is best out f the above?

  17. Abdullahi Suleiman says:

    Please who has an idea of how to design, construct and test a cupola furnance.

  18. vaibhav says:

    I want to insulate a copper piece of 80 degrees. Insulation thickness should be nearly 1 mm. Do you any material which can fulfill my need ?

    • Brian Bannon says:

      1mm is very thin and with copper you are going to need something flexible….I assume the copper diameter is less than 1.5″? if so an Armaflex Pipe insulation is probably best

  19. salman says:

    i want to put an insulation between two heat sinks,as one is to be hot and the other one is to be cold . my problem is its thickness should be only 3mm and it should be flat sheet.

    • The best insulation that I could recommend would be 5mm thickness of Pyrogel XT. The Pyrogel is referred to as “solid smoke”, the K factor is 0.14 with an R value of 7.14. I’m sure you could work the material down between your two heat sinks.

  20. vaibhav says:

    what will be the cost of armflex & where can i get it.

    • Price of armaflex will vary from supply house to supply house. Look up mechanical insulation suppliers on google and pick one in your area. Another avenue would be to call a local HVAC contractor and ask them about it. That is a product used often in HVAC applications.

  21. Shamkhal says:

    Hi. I would like to know if your firm delivers materials to Germany.
    If yes than can You please provide me with your prise list? We are
    interested in finding a large amount of material for our production.
    Thanks a lot.

  22. Shara Nursal says:

    Hi, my company would apply thermal insulation for our warehouse with 6 m of height and 10×10 m2 of dimension. Could you suggest best product for us?

  23. Pingback: Wood foam – The most promising new thermal insulation material | Chong Yin @ Econcore

  24. Shara,
    For a building of that size Fiberglass batts, or 2″ thick Styrofoam insulation would be the easiest to install.

  25. Twinkle says:

    I require thermal insulation for my glass door as the direct sunlight melts all my gelato. Please suggest the best thing.

  26. Will jones says:

    Dear Twinkle
    I would suggest going to a place that sells doors. They should have the window covering that blocks the sunlight, yet still allows you to see out. Another suggestion would be to put the gelato in the refrigerator.

  27. MEURICE says:

    Nice !!

  28. najeeha says:

    How about the material used in car interior (headliner fabric), polyester usually used for this purpose. why do you thing polyester is more preferable fabric to be used as headliner, it is because polyester is a good heat insulator? And what do you think about the relationship between thermal conductivity (k-value) and thickness, fabric weight and pore size (porosity)? Do you have any suggestion or recommendation regarding the suitable fabric for automotive headlining other than polyester to be applied as headliner for heat insulator?

  29. Dev says:

    What type of insulation is most suitable for a mushroom farm of size 70 x 22 x13 (LWH). Outside temparature in summar is 47°C and in winter 6°C. I would like to install a chiller system inside the room. Please help if puf panel is better solution. If so what should be its thicknes.

  30. ubong okon says:

    thanks for answers

  31. Vipul says:

    Please suggest me a solution for my problem, we have insulated our kiln with rockwool and covered with SS304 sheet 2 mm thick from outside we have welded the sealed the sheet air tight, but as the temperature inside the kiln reaches 700 degree centigrade it breaks the welded joints and the rockwool comes out.

    • Vipul,
      My first question would be, how thick is the mineral wool. The thickness dictates the touch temperature of the outer layer.
      Question 2: Is the insulation you are using rated to withstand that temperature
      Question 3: If the purpose of insulating the kiln is for personal protection then the touch temperature must be below 60C. with the parameters given that will require 10 inches of rockwool insulation.
      All the best

  32. Tulga says:

    Dear William Jones
    I am working on the project that will make Mongolian traditional tent called ger more modern . But the problem is Nomads, Mongolians, live in the tent for 4 seasons at from +40 to -40 c degrees and they move and carry it 4 times each year. I need the best insulation material for 10 centimeter wall space, which will keep warm temperature at -40 degrees during the winter. The ger has a door through which most of the heat is missed and has a window on its top which is open for a day. Please i need your help and i want to buy a lots of the materials from you. can you give me your advice and your contacts ASAP!

  33. Tulga,
    We emailed the pricing to you, all you need to do is place an order!

  34. Tenho um mini forno e necessito de uma placa de isolamento entre a base do forno eletrico e a superficie superior da arca congeladora, na qual o forno esta pousado, e gostaria de saber tambem se existe, quanto custa.

  35. Katherine says:

    I want to line a kitchen counter “garage” with an easy-to-install material to reduce the cold air from non insulated walls. Any suggestions? Do I go to a hardware store or a fabric store? Thanks in advance for suggestions.

    • Thermaxx Jackets says:

      Stop by a home depot or lowes. let them know the problem and they will be able to set you up with some Wall Panel insulation or duct board insulation. Both are very easy to install

  36. Akshay says:

    i am constructing a catalytic convertor for a 300cc engine with exhaust temperature around 800 C which kind of insulation is suitable

    • Thermaxx Jackets says:

      Sounds like a fun project! 800c is Hot….
      You are going to need ceramic insulation. You should google an industrial insulation supply house in your area. They can help
      Good luck

  37. Carlos says:

    I have a Kenwood bread toaster which the outside cover is untouchable when operating. My idea is to put some isolation around the inside of the cover as there is about 2 cm space between the heating plates ahd the cover. Could somebody give me an idea about some kind of sheet material that I can use? Thank you for the reply

    • Thermaxx Jackets says:

      My only concern is dust. Most of the insulating products used in boiler rooms are very dusty and not designed to mix with food. there are some good insulation that is 5mm that may do the job but again…the dust is a concern. Is sealed..away from the food product? what are the exact dimensions you have?

  38. anees says:

    which insulation material is best inside the house. Our building is not insulated from outside.

  39. david schmid says:

    i want to make a cold storage unit out of wood and a reflective material what material for 36 degrees with a aircoditioner and cold balt unit can any one help me. thank you dave.

    • Thermaxx Jackets says:

      you can use a foil faced insulation board (1″ should do it). OK to google search mechanical insulation supply in your area. Good luck

  40. Alvin says:

    I am working on a pyrolysis project. I got insulate the heating system of interior 500 C to exterior 100 C with a application of 2 -3 mm thick insulator… What can be the best material for it ??

    • Will Jones says:

      2 to 3 mm of space is not enough to insulate and reach your goal of 100 C. 5mm of Pyrogel XT-E will reduce the temperature from 500 C to 175 C, that is far above your goal. The challenge is the 2 to 3mm of space. 15mm of Pyrogel XT-E would reduce the temperature to 99.7 C and 20mm of Pyrogel XT-E would reduce the temperature to 85.22. The bottom line, you need more annular space.

  41. David says:

    I going to be building a powder coating oven its going to be 6x6x7 using inner and outer walls made of 18 gauge sheet metal thinking of metal 2×4 studs what type of insulation should I use to keep my interior of the oven at 500 to 700 degree with out burning up the insulation .I will be using electric elements for the heating .

    • Will Jones says:

      I am going to assume that when you say 500 to 700 degrees you are using Fahrenheit. At 700F the BTU loss per SF/HR is 3115.0, with 2″ of type E needled fiberglass (often times called “tempmat”) the BTU loss will be reduced to 120.8 BTU’s per SF/HR the efficiency is 96% and the touch temperature is 139F. You can obviously use a thicker insulation however you need to look at the economy of scale, is it worth the cost to put more insulation on. To obtain the Tempmat or type E needled fiberglass you can find a local Mechanical insulation supplier.
      Good Luck

  42. Jessica Montgomery says:

    I am looking at retrofitting railroad boxcars with an insulator so that they can be used in the shipment of canned goods. When the cans are shipped without an insulator they become very cold but do not freeze due to the vibrations of the car. However condensation forms on the cans when they are removed from the boxcar and placed in a warmer storage warehouse. Rust forms on the cans and the product is lost. The cans will be on the cars for an absolute maximum of 2 weeks but more typically 4-5 days and they ship through the northern united states. because the insulation is going on the inside on the boxcar I need an insulation that will not cause irritation to operators loading the cars. Can I get information on the thermal properties of your insulators as well as pricing information?

  43. megha says:

    which insulating material is best for stainless steel pipe at 250 degree C.

    • Thermaxx Jackets says:

      250c is in the range for most of the insulation materials on the market. If indoors, and not exposed to weather, a needled fiber glass will work well

  44. Jack says:

    I’m trying to insulate a small camera with circuitry components (like capacitors and IC chips) on a printed circuit board (around 5.5cm square). The temperature of operation will be around 60 to 100C. What would be a good material to use?

  45. S. K Mohapatra says:

    I want to insulate the outer wall of a U-shaped jacket of an equipment. The jacket has heated thermo-oil at 250 degree Celsius. Insulation is required on the outer wall of the jacket to keep touch temperature below 50 degree Celsius. Please advise most economical material & its thickness.
    S. K. Mohapatra

  46. haresh vashi says:

    LRB of 75mm thickness can do with 120 kg/m3 if is indoor.

  47. Suhad says:

    I heard there z a material called “silk plaster” or “liquid wallpaper” used for insulation. It z a combination of cotton silk and cellulose.. All z natural material. I need to know f it z effective in temperature insulation or not. Plz f anyone has review

  48. mehul says:

    our project based on effect of temperature and pressure on composite material.temp rangd is upto 400 degree celcius…than what kind of insulation is provide at this range?

  49. msc rao says:

    we are trying to develop battery enclosure for extreme temperature(for high and low around +60 degree and -30 degree. our battery nominal working temperatures are +40 and -0 degrees. to enhance working temperatures of batteries we are trying to insulate battery enclosures.please suggest best insulating material and thickness

  50. You have lots of useful info and I’m glad I found this site for my school science fair

  51. Chrys says:

    I need an insulating material to use for a thermoelectric wine chiller, any suggestions as to which material would be best suited and why ?

  52. bosi says:

    what is the most sutiable insulator matrial at the desert in egypt ??

  53. Pingback: Insulating Under a Mobile Home with Foam Board (DIY Project)

  54. simmmi says:

    i want to know which type of insulating material is good for insulating solar box cooker. my senior has used stryo foam and i want to use something else which is available at low cost

    • Thermaxx Jackets says:

      You may want to stop by your local home depot and get some tank insulation board. You can also purchase it online

  55. Luke says:

    Hi there I need to insulate mild steel metal tubing next to camp fire, I’m trying to prevent the metal from absorbing the radiant heat so it remains a low enough temperature that it can be touch by a bare hand.

  56. Rahul says:

    Which insulating material is suitable for covering the pipe having diameter 165 mm? and Why?

    • Will Jones says:

      There are many factors that one would need to know before making a selection of insulation material. What is the Temperature of the fluid in the pipe, is the application indoors or outdoors, is the application subject to wash down activities. If you can give the needed information I can tell you what insulation I would use and why I would use it.

  57. Ed Stephens says:

    I have to replace the doors on several walk in ovens which operate between 350-400 degrees. What would be my best choice to complete this job ?

  58. Rudresh Shukla says:

    hey i am doing project.. in this i have a problem regarding fire resistance of steel jacketing of beam, column… i need material to coat it around the beam and column any suggestions??

  59. alexander burkhardt says:

    I have to isolate an aluminum roof of 2000 m2.
    The outside temperature is around 40 degree C and there is often heavy rain.

    Any ideas?

    Thank you.

  60. Shoaib javed says:

    I need to insulate a stainless steel chamber..inside temp is 70 degree celsius…which material is best and how much thickness

    • Will Jones says:

      To insulate a Stainless Steel tank at 70C or 158F there are several choices. If the application is outdoors we would recommend 10mm of Pyrogel XT-E aerogel insulation. Aerogel insulation is hydrophobic and will not absorb liquid water.
      If the application is indoors you have several choices:
      1) 1″ of mineral fiber pipe and tank insulation
      2) 1″ of type E needled fiberglass insulation
      3) 1″ of elastomeric or closed cell insulation.
      We hope this helps.

  61. billy mcpeterson says:

    I did an experiment in my beach house’s attic by using cotton candy as an insulator.

    Didn’t work.

    Don’t attempt.

  62. John says:

    I really liked the graph highlighting the types of insulation commonly used. It mentioned that fiberglass and mineral wool are really the only types that aren’t flammable. I’d imagine having insulation that is flame-resistant would be really important especially in an industrial setting.

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