When deciding on which insulation type to use, it can be difficult to figure out the differences between all the options on the market. Knowing what makes each insulation type special will help you make an informed decision. Insulation is one of the most important parts of your building, so it is a decision you will want to get right.
The Importance of Insulation
Insulation is incredibly important to a building’s performance and longevity although it often does not get the credit it deserves. The main role of insulation is to slow down the transfer of heat into and out of the building. By slowing down this rate of heat transfer, the building’s HVAC does not have to use as much energy to keep the building comfortable.
In addition to energy efficiency, some other benefits of insulation are:
Noise Reduction
Buildings with little or no insulation tend to be very loud. Insulation reduces the noise from loud sounds outside and prevents sound from being able to echo off the building’s walls internally. Without insulation, noise can reverberate throughout the building. Insulation acts to dampen these sounds, keeping them from getting louder and making your building more enjoyable to be in for all occupants.
Fire Resistance
Code requirements require insulation to pass a minimum fire rating test. Buildings with insulation make it harder for a fire to spread throughout the building. Not only can this reduce structural damage in case of a fire, but it will also reduce the likelihood of fire-related injuries to building occupants.
Thermal Comfort
Insulation helps to slow down heat transfer into and out of the building, and also keeps the temperature in a building more consistent. Without proper insulation, a building is more likely to have hot and cold spots throughout. Thermal comfort keeps occupants more productive and reduces the variability in how your HVAC equipment operates.
EPS and XPS: What’s the Difference?
Expanded polystyrene (EPS) and extruded polystyrene (XPS) are both popular forms of insulation and while similar, they do have their differences.
Composition
XPS is made via an extrusion process, resulting in a closed cell structure and a smooth layer on the top and bottom sides of the board. The closed cell structure of XPS prevents water penetration into the insulation and gives XPS enhanced strength and durability
EPS is made using beads of foam instead of an extrusion process. The beads are placed into a mold and then heated to fuse them. Since voids can occur between the beads, the insulation is not a closed cell board and is less resistant to water.
Thermal Conductivity
One of the key parameters for any type of insulation is its thermal conductivity. XPS and EPS are both popular insulation types because they both have low thermal conductivity. EPS has pockets of air trapped inside the foam board, so XPS typically outperforms EPS. High-density EPS is closer in performance to XPS, but XPS still usually performs better.
Compressive Strength
For some applications, the insulation’s compressive strength becomes very important. Concrete floors, flat roofs, foundations, and cold storage all put more stress on the insulation. XPS is typically stronger in compression than EPS, requiring thicker, higher-density versions of EPS to match XPS insulation’s performance.
Water Vapor
Often a deciding factor for when to use XPS versus EPS is the ability to resist water vapor diffusion. Water vapor can travel through insulation and into the building. The closed-cell nature of XPS makes it much more difficult for this to occur. In wetter locations, XPS is usually selected over EPS.
Polyiso: the Better Alternative
Polyisocyanurate (polyiso) provides a superior alternative to both EPS and XPS insulation. Polyiso is a completely different kind of plastic, a thermoset instead of a thermoplastic. When exposed to high heat, XPS and EPS soften and melt. Polyiso, on the other hand, simply chars.
The structure of polyiso tends to be stronger than XPS or EPS due to the bonds of its chemical makeup. Polyiso has a three-dimensional network of bonds or cross-linking, that gives it both strength and high-temperature durability. This durability helps polyiso keep its shape and high performance better than XPS and EPS.
Polyiso is higher-performing insulation with thermal conductivities better than XPS. Even with exceptional performance, polyiso is still comparable in cost with XPS and EPS, based on its lower price per R-value per inch. Polyiso matches or exceeds the performance of both XPS and EPS including being more sustainable for the environment, having higher thermal performance, greater fire resistance, thinner wall profiles, and better moisture management and air infiltration reduction.
Find the Best in Polyiso with Rmax
At Rmax, our mission is to take the best polyiso insulation available and maximize its performance even further. When choosing the insulation for your building, reach out to our experts at Rmax today to learn more about why Rmax’s polyiso wall insulation is the best choice.