At Quarve Contracting, we believe homeowners deserve clear, honest information about the materials protecting their home. This guide explains the four most common types of rigid foam insulation used in Minnesota homes — XPS, EPS, Polyiso, and GPS — so you can feel confident in the choice we recommend for your project.

What Is Rigid Foam Insulation?

Rigid foam insulation is installed on the exterior of your home to improve energy efficiency, reduce drafts, prevent moisture issues, and increase overall comfort. It acts like a warm “blanket” around your home’s structure.

Different types of foam offer different benefits. Here’s how they compare.

Rigid Foam Comparison

GPS (Graphite‑Enhanced EPS) — Our Preferred Choice

Best overall performance for Minnesota homes

  • Excellent insulation value, even in very cold weather

  • Helps your home “breathe” by allowing moisture to dry outward

  • Environmentally friendly

  • Great long‑term performance

  • Ideal for siding replacement and energy‑efficient upgrades

Why we recommend it:
GPS delivers the best balance of comfort, efficiency, and durability for Minnesota’s climate.

XPS (Extruded Polystyrene)

Best for below‑grade or high‑moisture areas

  • Strong moisture resistance

  • Good insulation value

  • Durable and rigid

Where it’s used:
Basement walls, foundations, and areas with soil contact.

EPS (Expanded Polystyrene)

Most budget‑friendly option

  • Good long‑term performance

  • Allows moisture to dry outward

  • Cost‑effective

Where it’s used:
General exterior insulation, roofing systems, and insulated panels.

Polyiso (Polyisocyanurate)

High R‑value — but only in warmer temperatures

  • Very high insulation value in warm weather

  • Often used in commercial roofing

  • Foil‑faced versions act as vapor barriers

Limitations:
Polyiso loses insulation value in cold weather, making it less ideal for Minnesota exterior walls.

Which One Is Best for Your Home?

For most Minnesota homes:

👉 GPS (Graphite‑Enhanced EPS)
It performs consistently in cold weather, supports wall drying, and improves long‑term energy efficiency.

For basements or below‑grade areas:

👉 XPS

For budget‑focused projects:

👉 EPS

For commercial or warm‑climate applications:

👉 Polyiso

Why Homeowners Choose Quarve Contracting

  • Over 40 years of exterior remodeling expertise

  • Minnesota‑specific building science knowledge

  • Premium materials selected for long‑term performance

  • Clear communication and transparent recommendations

  • Workmanship backed by industry‑leading warranties

Your home deserves insulation that performs in our climate — and a contractor who understands how to install it correctly.