If you want to know who would be the winner in the direct competition between EPS vs XPS foam, you are in the right place. This article mentions factors to consider when comparing the two to truly know which one is good and a better fit for you.
Let’s start off with what these plastic foams are, to better compare them
What is EPS foam?
Expanded Polystyrene (EPS) is a closed-cell, rigid, and lightweight foam that is created by expanding Polystyrene resin or beads. This expansion is done inside moulds that resemble the shape of blocks, creating small EPS blocks. These blocks are then further cut into small sheets of variable size and thickness to suit daily needs. Some other common names of EPS sheets are Thermocol/Thermapor sheets.
EPS is not the same as Styrofoam. It is most commonly confused with Styrofoam due to having a similar appearance but the two have different manufacturing processes and results.
What is XPS foam?
Extruded Polystyrene (XPS) is a closed-cell thermoplastic foam that is durable, flexible, and used for insulation purposes all around the world. XPS foam is made up of a material called Polystyrene, which is further achieved through the polymerization of a petroleum-based product called Styrene. Another fact about XPS foam is that it is the exact same as Styrofoam. The name Styrofoam is just a trademarked brand name for Extruded Polystyrene (XPS), which was patented in 1944.
The main difference between XPS and EPS foam is in the manufacturing process. EPS foams undergo expansion while XPS foams undergo extrusion. This results in different materials with different properties.
Factors for comparing EPS vs XPS foam
If we want to truly get to the bottom of this issue, we have to analyze the properties that set each of these foam boards apart.
Thermal Resistance
Before discussing thermal resistance, we need to discuss the R-value as it is crucial to know which foam board is better at insulation. The thermal resistance of different products is measured in their R-value, where R stands for Resistance. So the higher the R-value, the higher the insulation. XPS foam has a higher R-value than EPS foam in general.
This is due to there being more air pockets in EPS foam boards from undergoing expansion. The Polystyrene beads fuse when expanded inside a mould but not every small open space is covered by the expanding beads. This leads to air being trapped inside, and since air is a conductor of temperature, EPS sheets become poor insulators as compared to XPS sheets, which undergo extrusion and have significantly less number of air pockets.
Compressive strength
XPS foam in general has a higher compressive strength than EPS foam. Known as the resistance to break under compression, both foams have amazing compressive strength as they are used in shock absorption for transporting cargo, and goods. The slight difference is due to the uniform structure of XPS foam which makes it more resistant to compression. The general values for compressive strength of XPS foam range from 15 to 60 psi while in comparison, EPS foam is typically between 10 to 40 psi.
Water Vapor Permeance
When it comes to comparing the permeance, the lower it is the better the material is at insulation. XPS has a lower amount of permeance, meaning it is less permissible to water and moisture than EPS. The specific values of permeance for XPS foam are around 1.1 to 1.5 perms at around 1 inch of thickness while EPS foam for the same thickness has around 3.5 to 5 perms.
EPS foam absorbs more water due to there being tiny air pockets in its structure. Rather than XPS which is extruded through a tight space, which results in a smoother surface at the top and the bottom. While EPS sheets of various densities can also be manufactured to lower their perm value, on average the XPS sheet is the clear winner.
Cost
EPS costs less than XPS foam on average. The cost varies depending on the density and thickness of the foam itself, but on average XPS foam is more expensive.
This is due to the higher manufacturing costs required to produce XPS. The extrusion process required to manufacture it utilizes advanced technology and more energy as compared to EPS foam. Due to having better compressive strength, thermal conductivity, and water vapor permeance, the cost of XPS rises up even further as compared to EPS.
Overall, If cost is the main factor in your final decision, EPS sheets are the right choice as they are more affordable and a budget-friendly version of XPS.
Popular uses of EPS vs XPS foam
Both are highly versatile and can be used in several ways in various industries. If you are curious as to if your intended use falls in this category, then continue reading.
Uses of XPS foam
Following are the most popular uses of XPS foam around the world
- Roof insulation: XPS offers excellent thermal insulation and is the ideal choice for insulating roofs, both flat and sloped. It can be used in false ceilings and inverted roofs to provide moisture resistance and Thermal Insulation
- Under Concrete Slabs: Due to their high compressive strength and low moisture permeance, XPS sheets are used for insulating concrete slabs.
- Model building: Whether it’s for creating different terrains, dioramas, or 3D designing, XPS is an excellent material for all model-making activities as they are easier to cut and mold.
- Refrigeration: To protect from external temperature and moisture fluctuations, XPS sheets are used to insulate refrigerators and even whole cold storage rooms
- Control rooms: Xps foam is used in lining material for insulating control rooms, the most popular being server rooms, poultry control sheds, and more
Uses of XPS foam
EPS foam is quite good at its own set of applications. The most popular and common uses of EPS foam are
- Packaging: Most EPS is used to package common goods such as glassware, electronics, medicine, and food.
- Insulation: Being the cost-effective alternative to XPS, EPS sheets are widely utilized in building insulation to reduce energy consumption. EPS is a thermal insulator and while not as comparable to XPS, it still can keep buildings warm in the winter and cool in the summer.
- Decorated tiles and molding: To cover up transitions and gaps in surfaces, decorated EPS tiles are used. Due to their customizable nature, they can be easily shaped and painted to match a specific design.
- Structural Insulated Panels (SIPs): Utilized in walls, roofs, and floors to provide structural support, SIPs are widely used in the construction industry. They are three layered panels with a core sandwiched between facers. The core is mostly EPS foam which is bonded to two Oriented Strand Boards(OSBs) to provide excellent insulation.
- Geofoam: An alternative to traditional fill materials which is also inexpensive. EPS foam used as geofoam is utilized in backfilling bridge abutments and any areas where lightweight fill is required
It is clearly evident that XPS is the better option amongst the two when comparing their attributes, but EPS foam is still a close second as it also provides solutions at an affordable cost. In the end, both have their advantages and disadvantages, so when choosing between the two, it is important to consider the budget and intended use to make the right choice
