EPS vs XPS vs Polyiso: Which Insulation Is Best for Massachusetts Homes and Buildings?
Choosing the right rigid foam insulation can be the difference between a drafty structure and one that performs efficiently for decades. In New England’s unpredictable climate — where a single day can swing from frost to thaw — insulation isn’t just a material choice, it’s an investment in comfort, sustainability, and cost control.
At Green Insulation Group, we specialize in reclaimed rigid foam boards — the same high-performance materials used in commercial construction, repurposed to reduce waste and cost. But which type is best for your project? Let’s explore the differences among EPS, XPS, and Polyiso, and how each performs in Massachusetts conditions.
EPS (Expanded Polystyrene): The Budget-Friendly All-Rounder
EPS, often recognized by its white bead appearance, is one of the most versatile and affordable insulation types.
R-Value: 3.6 – 4.2 per inch
Best Use: Under slab foundations, wall sheathing, and roofing in moderate exposure conditions.
EPS performs well in below-grade applications where moisture management is key — especially when paired with proper drainage and vapor barriers. In Massachusetts homes, it’s often used under basement slabs and garage floors to prevent heat loss into the ground.
Its biggest advantage? Cost and recyclability. EPS is easy to source, lightweight, and fully reusable — making reclaimed EPS panels a sustainable option for contractors and homeowners alike.
XPS (Extruded Polystyrene): The Durable Workhorse
XPS is known for its smooth, closed-cell structure and exceptional resistance to water absorption. Its blue, pink, or green coloration varies by manufacturer, but its performance remains consistent.
R-Value: 4.7 – 5.0 per inch
Best Use: Exterior walls, foundation insulation, and beneath slabs.
Because of its water resistance and compressive strength, XPS is the go-to choice for below-grade foundation insulation and perimeter drainage protection — especially in Massachusetts homes where spring thaw and coastal humidity can test even the best building envelopes.
Reclaimed XPS boards from Green Insulation Group maintain their structural integrity, offering the same R-value as new boards at a fraction of the price.
Polyiso (Polyisocyanurate): The High-Efficiency Performer
Polyiso, or Polyisocyanurate, is the insulation of choice for projects that demand maximum R-value per inch — perfect for attics, roofs, and wall assemblies where space is limited.
R-Value: 5.6 – 6.8 per inch
Best Use: Roof and wall insulation, especially in retrofit or high-efficiency builds.
In New England climates, Polyiso shines when used above grade with appropriate weather protection. It offers superior thermal performance but can lose R-value slightly in extreme cold, so installation techniques matter. Pairing Polyiso with a thermal break or combining layers with EPS can yield exceptional year-round results.
At Green Insulation Group, we stock reclaimed Polyiso panels from major commercial projects, making high-R insulation accessible for residential and small business retrofits.
Massachusetts Applications: What Works Best Locally
Our climate demands insulation that resists both moisture and temperature extremes. Here’s how each material typically performs in common Massachusetts scenarios:
| Application | Recommended Type | Why It Works |
|---|---|---|
| Basement/Foundation Walls | XPS or EPS | Handles ground moisture and freeze–thaw cycles. |
| Attics & Roofs | Polyiso | Delivers highest R-value where space is limited. |
| Exterior Sheathing | EPS or Polyiso | Lightweight, easy to cut, adds continuous insulation. |
| Slab Insulation | XPS | Strong compressive strength for bearing loads. |
Because Green Insulation Group offers reclaimed boards, you can mix materials strategically without overspending — a big advantage for contractors optimizing both performance and sustainability.
The Sustainable Advantage: Reclaimed Foam Boards
Each reclaimed panel you purchase prevents high-quality insulation from entering the waste stream. Reuse also means avoiding the emissions associated with new manufacturing. Builders across Massachusetts and southern New England are turning to reclaimed EPS, XPS, and Polyiso as the smarter, greener alternative to new foam boards.
Reclaimed insulation offers:
-
40–70% cost savings versus new products
-
Lower embodied carbon footprint
-
Same structural and thermal performance when sourced from reputable recyclers
Our reclaimed boards are inspected, sorted, and delivered ready to install — ensuring that sustainability doesn’t come at the expense of quality.
Save on Heating Costs This Winter — Available Now in Massachusetts
As colder weather approaches, reclaimed foam insulation can make a dramatic difference in home efficiency. Whether you’re insulating a basement, upgrading a roof, or preparing a commercial renovation, our stock of reclaimed EPS, XPS, and Polyiso boards is ready for pickup or delivery across Massachusetts.
Call us today or request a quote to find out how much you can save — both on energy and materials — this winter. Serving Massachusetts, New Hampshire, Rhode Island, and Connecticut. Sustainable. Affordable. Locally supplied.