Polystyrene vs Polyurethane: Understanding their Differences

When talking about building materials, two items often confuse consumers. These are Polystyrene and Polyurethane. These two materials differ from one another in terms of their functions even if they have the same prefix. This blog will help you determine the difference between the two in terms of insulation, durability, and cost to name a few to help you decide which material to use for your building needs.

Polystyrene and Polyurethane



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What is Polystyrene?

Polystyrene or PS for short is a type of plastic made up of linked styrene molecules. This material is hard and brittle which can be fragile but offers good insulation characteristics. In terms of cost, it is on the cheaper side which is why it is often used for disposable food containers, packaging materials, crafts, and as insulation for buildings.




What is Polyurethane?

Polyurethane or PU, when compared to Polystyrene has more applications. It has various types which can be rigid or flexible, have good thermal insulation properties, and are resistant to water, chemicals, and even fire. It has different features which make it more expensive than Polystyrene.



What are their Differences?

The following are the key comparisons between Polystyrene and Polyurethane to help you decide which one to choose:


1.       Insulation


PS has a moderate level of insulation that deteriorates over time especially if exposed to moisture or high temperatures. You will need a thicker layer of PS to attain the same level of PU because its R-value or resistance to heat flow is lower compared to PU.



PU has better thermal insulation than PS. Its insulating capability is excellent which is ideal for high-level requirements. It also has a higher R-value than PS making it more efficient and effective in maintaining the standard temperature.


2.       Durability


PS is hard and brittle which makes it susceptible to damage. It can be easily damaged by impact, dissolved by chemicals, and has a relatively shorter lifespan because of its fragile nature.



PU is a strong and resistant material. It can last longer, has resistance to water and some chemicals, and is more durable. Unlike PS, it can withstand pressure or impact and offers higher resistance to water, fire, and chemicals.


3.       Density


Polystyrene is a lightweight material that is often chosen because of this property. If weight is an issue, especially for packaging material, PS will always be a good choice.



Polyurethane has more density which is why it is more suitable for heavy-duty applications. It is stronger and can withstand more damage than polystyrene.



4.       Fire Resistance


Polystyrene as a material does not have high fire resistance. It easily catches on fire and spreads quickly, moreover, when burning, it releases harmful gases that are health hazards.



Most types of polyurethane have high fire resistance capabilities because of the formulations they use in treating them. Some polyurethane materials even have self-extinguishing properties that make them safe for use.


5.       Moisture Resistance


Polystyrene materials have relatively low water resistance. When exposed or subjected to water it can absorb it over time resulting in decreased insulation capability and weakened structure.



The way polyurethane is made is that its molecules are placed in a way that enhances water repulsion therefore it creates higher moisture resistance.


6.       Cost

Polystyrene and Polyurethane Cost



Cheaper and more affordable which makes it popular for mass production.



More expensive than polystyrene but performs better.


7.       Comparison of their R-Value


Has a good R-value which falls between R-3.0 to R-4.0 per inch but deteriorates over time due to aging. It needs to be thicker in layers to achieve the level of polyurethane.



Polyurethane has a higher and more excellent R-value, ranging between R-0.60 to R-0.75 per inch making it a better insulator than polystyrene. It does not deteriorate over time and a thin layer of it is comparable to a thick layer of polystyrene.



Types of Polystyrene and Polyurethane:

Now that we have identified the differences between Polystyrene and Polyurethane let us now delve into the various types of both.


1.     Polystyrene Types:

Expanded Polystyrene (EPS):

The most common type of Polystyrene that provides decent insulation. You may recognize these as lightweight, white packaging materials or disposable containers but are sometimes used as insulation for buildings.

Expanded Polystyrene (EPS)


Extruded Polystyrene (XPS):

The stronger and denser type of Polystyrene which has a higher R-value. It is also water-resistant which makes it a good option as insulation for buildings.


2.  Polyurethane Types:

Rigid Polyurethane Foam:

Commonly used as insulation for buildings specifically on walls and roofs because of its structure which provides good thermal insulation, energy efficiency and water resistance.


Open-cell PU Foam:

Open-cell foams provide good insulation aside from allowing air to pass through which is a good option for applications where airflow is desired.


Closed-cell PU Foam:

This type of foam is the opposite of the open cell. It has good water resistance and insulating properties that are useful in applications such as marine products, pipe insulation, and flotation devices.

Closed-cell PU Foam

Flexible Polyurethane Foam:

Based on its name, this material’s flexibility is its selling point. It can be made soft, firm, or bouncy which are good options for furniture paddings, soles, and even car parts.


Polyurethane Coatings & Adhesives

As a coating or adhesive, polyurethane is a good choice due to its water and chemical resistance, and its bonding properties. Typically used as coatings for flooring, furniture, and other industrial applications.



Polystyrene vs. Polyurethane: A Comparison of Their Applications

Polystyrene and Polyurethane, though may seem the same, have different applications that take advantage of their unique properties. The following are some of the applications where both may excel.


1.       Polystyrene:

Polystyrene’s affordability and low cost make it the best option for the following applications:


Cost-effective Packaging

Usually placed and used in packaging to protect fragile items during transport and shipping.


Disposable Food Containers

The lightweight property and low costs make polystyrene the best choice of  material for disposable cups, plates, and containers

Disposable Food Containers


Low-cost Building Insulation

It may not be the best material to be used for building insulation but it can still get the job done, especially for projects with a tight budget.


Craft and Hobby Materials

As stated earlier, polystyrene is light and affordable which is why it is a popular material for projects and hobbies without spending too much.

Craft and hobby materials


2.       Polyurethane

The characteristics and properties of polyurethane make it the best choice for the following applications:


Appliance Components

The insulation properties of polyurethane help maintain a consistent temperature in refrigerators and freezers. Its durability and water resistance helps keep appliances last longer.

refrigerators and freezers

Cold Room Storage

The closed-cell type of polyurethane is best used in refrigeration systems because it does not let air flow through it. It keeps the ideal temperature consistent due to its excellent insulating properties.


Pre-engineered Metal Buildings

The high water and moisture resistance of polyurethane together with its good insulating capability enables it to be used as support for structures on buildings.


Medical Applications

The flexibility of polyurethane materials allows it to be molded into different things. It is made of safe materials which is why it is used in the hospital industry as tubing in catheters, prosthetics, and implants.



The excellent insulation polyurethane provides helps prevent malfunctions and short circuits in electrical components


High-Performance Building Insulation (Wall, Roof, and Floor Insulation)

The spray foam variant of polyurethane is one of the best building materials for energy efficiency by filling cracks and gaps to prevent the temperature from decreasing while providing resistance to moisture and water.


Aerospace Applications

Some special types of polyurethane can withstand the pressure of aerospace environments coupled with their durability and weight which is why they are sometimes used as materials for aerospace applications.


Furniture Cushioning and Padding

The durability of polyurethane makes it an excellent padding for furniture. They are used as cushions to provide comfort without the risk of damage due to wear and tear.

polyurethane makes padding for furniture


Construction materials

The adhesive and coating applications of polyurethane provide water resistance, bonding strength, and chemical resistance for construction materials.



Key Considerations when Choosing between Polystyrene and Polyurethane:

In choosing between Polystyrene and Polyurethane, you may consider the point stated below:


1.       Application of the Specific Needs

Determine the requirements needed and the way you are going to use the material. The factors to consider are the temperature, moisture exposure, the type of environment, and other safety regulations.


2.       Project Requirements

For projects, determine the purpose and the level of performance needed. The durability, aesthetic appeal, and costs are also some factors to consider while keeping in mind the different regulations and procedures existing within your area.

Project Requirements


3.       Initial and Long term cost

Do not just opt for the cheaper option. Think about the initial and long-term expenditures before choosing between the two. While PS is cheaper at first glance, the superiority of PU in performance may eventually lead to efficiency and savings.


4.       Environmental Impact

Always keep in mind that the environmental impact of the materials is also an important point to consider. Polystyrene though cheap is difficult to dispose of. There are polyurethane products that are bio-based but not widely available.


5.       Regulations and Building Codes

Equip yourself with the knowledge of the different building codes and regions before choosing between the two so that you are assured that the material you choose complies with the existing requirements of the area.

Regulations and Building Codes


6.       Availability and Lead Times

Polystyrene though cheap, can contend with Polyurethane in some respects. It is also popular which is why it is readily available and easy to deliver, while polyurethane takes longer to deliver if not pre-ordered which can affect the working schedule of projects.


7.       Processing and Installation

 Polystyrene is easy to cut and install because of its characteristics while polyurethane requires a certain level of techniques when handling. Look at your current skill level and the difficulty of the project to help you choose the right material.


8.       Safety During Use and Disposal

Equip yourself with the knowledge of how to properly dispose of both materials. Always prioritize your safety and health which is why you also need to consider the possible risks that each type of material provides.


9.       Maintenance and Repair

In project planning, the maintenance and repair needs are always part of the plan. Polystyrene is easy to maintain but is brittle which makes it susceptible to damage. Polyurethane materials are more durable and require minimal maintenance which makes it a better option if you are not on a tight budget.





There are no best insulating materials. The best insulation is the one that fits the requirements of the industry. In this blog, we compared the different aspects of Polystyrene and Polyurethane, explained some key concepts, and considered some factors. No matter what material you choose, always keep in mind the things that we talked about today to help you pick the best option among the two.

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