What’s the difference between standard EPS and Graphite Infused EPS?

At Formance SIPs, we offer two insulation options for our Structural Insulated Panels (SIPs)

  • Standard White Construction Grade (EPS)
  • Graphite Infused Construction Grade (GRP)

They both come from a virgin material that is expanded using steam and then molded into large blocks. The difference with the graphite Infused EPs is that graphite particles are added to the raw materials. This gives the Graphite Infused EPS a grey colour.

Both provide excellent thermal performance, but GRP unlocks a secret weapon for superior insulation without sacrificing wall thickness as it offers an upgrade in R-Value of approximately 18%, depending on the thickness of the Formance SIPs panel

Standard White EPS: A Reliable Choice

This well-established material offers a balance of affordability and proven performance. Its high R-value effectively traps air, slowing heat transfer. The more popular choice, it’s easier to recycle and is commonly used for projects where a balance of performance and cost is required. 

Graphite Infused EPS (GRP): The Efficiency Champion

GRP incorporates graphite particles, boosting its ability to resist temperature. This translates to superior thermal performance compared to standard EPS. Due to this increased efficiency, GRP panels can be thinner than EPS while achieving the similar R-values. This allows you to maximize valuable interior space without compromising insulation. This feature is particularly crucial for clients aiming for the stringent energy standards of Passive Houses, known for their ultra-low energy consumption.

Choosing Your Ideal Insulation

The best choice depends on your project's specific needs. Here's a simplified breakdown:

  • For cost-effectiveness and moderate climates, standard EPS is excellent.
  • For superior energy performance, especially in colder climates or Passive House projects where space optimization is crucial, GRP might be a better option.

For a scientific answer, we’d recommend getting your home thermally modeled with our Passive House Planning Package (PHPP) software. It allows you to know exactly how much energy your home will consume, and then value engineer different product choices to suit.


Reach out to the Formance team on 0800 000 527 or email [email protected] to learn more.

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