Materials Comparison: Common Thermal Barriers and Their Uses
Understanding the differences between thermal barrier materials helps homeowners, builders, and retrofitting professionals choose solutions that balance energy efficiency, comfort, and cost. This article compares common insulation types, explains thermal conductivity and practical applications, and outlines where draftproofing and air sealing complement material choices for measurable savings.
Materials Comparison: Common Thermal Barriers and Their Uses
Selecting the right thermal barrier for a building affects energy use, indoor comfort, and long-term savings. This article explains common options—foam, fiberglass, cellulose, rigid boards and mineral wool—how conductivity and installation influence performance, and how retrofit measures like draftproofing and air sealing tie into a broader efficiency strategy.
What are common thermal materials?
Common thermal materials used in walls, attics, roofs, and cavity fills include fiberglass batts, cellulose loose-fill, mineral wool, open- and closed-cell spray foam, and rigid board insulation (polyiso, XPS). Each material is a thermal barrier that slows heat transfer; choices depend on the installation location, whether you need air sealing, moisture resistance, fire performance, or sound attenuation. Materials also differ in embodied energy and recyclability, which can influence sustainable specifications.
How does conductivity affect energy efficiency?
Thermal conductivity (and its inverse, R-value) describes how readily heat passes through a material: lower conductivity and higher R-value mean better resistance to heat flow. Buildings in colder climates prioritize higher R-value per inch, while temperate climates balance insulation with ventilation. Conductivity interacts with installation quality: gaps, compression, or poor coverage will reduce real-world effectiveness. To maximize energy savings, pair appropriate material R-values with proper installation and continuous insulation where feasible.
Where to focus: retrofit, draftproofing, and airseal?
When retrofitting an existing building, identify air leaks and thermal bridges before adding bulk insulation. Draftproofing around windows, doors, and service penetrations plus a targeted airseal of attic and floor junctions can often deliver significant comfort gains and reduce heating/cooling loads. Air sealing is complementary to insulation: a well-sealed envelope means insulation performs closer to its rated value and occupants notice reduced drafts and more even indoor temperatures.
Applications: attic, cavity, and cladding
Attics are commonly insulated with blown cellulose or fiberglass because they can fill irregular cavities; spray foam is also used when air sealing and moisture control are priorities. Cavity insulation (between studs) favors batts or dense-packed cellulose for retrofit access. Cladding and exterior continuous insulation typically use rigid boards (polyiso, XPS) to reduce thermal bridging through studs and improve whole-wall performance. Consider ventilation, vapor control, and roof assembly compatibility when choosing a material for these applications.
Foam, fiberglass, and cellulose: performance and comfort
Open-cell foam excels at filling gaps and improving comfort by reducing air movement, though it has a lower R-value per inch than closed-cell foam. Fiberglass is cost-effective and DIY-friendly but relies on precise installation to avoid gaps or compression. Cellulose, made largely from recycled paper, offers good cavity fill and sound attenuation and can be dense-packed for retrofit walls. Comfort outcomes—reduced drafts, steadier indoor temperatures, and quieter rooms—depend on matching material properties to the installation context.
Cost and product comparison
Real-world cost and provider performance vary by material, installation complexity, and region. Below is a concise comparison of representative products and manufacturers to illustrate typical features and ballpark cost ranges. These entries reflect common market offerings and should be treated as estimates rather than fixed prices.
| Product/Service Name | Provider | Key Features | Cost Estimation |
|---|---|---|---|
| Fiberglass batts | Owens Corning | Pre-cut, DIY-friendly, suitable for stud bays | $0.30–$0.60 per sq ft (material only) |
| Mineral wool (stone wool) | ROCKWOOL | Fire-resistant, sound control, moisture tolerant | $0.60–$1.20 per sq ft (material only) |
| Cellulose loose-fill (blown) | GreenFiber / Applegate | Recycled content, good for attics and retrofits | $0.50–$1.00 per sq ft installed |
| Open-cell spray foam | Icynene | Air-sealing, expands into cavities | $1.00–$1.50 per sq ft installed |
| Closed-cell spray foam | Demilec / Dow systems | Higher R-value per inch, moisture barrier | $1.80–$3.00 per sq ft installed |
| Rigid polyiso / XPS boards | Kingspan / Dow | High R-value per inch, used on roofs and cladding | $0.80–$2.00 per sq ft (material) |
Prices, rates, or cost estimates mentioned in this article are based on the latest available information but may change over time. Independent research is advised before making financial decisions.
These cost ranges reflect typical material and installed prices in many markets but will shift with labor rates, regional supply, job size, access, and local codes. For accurate budgeting, obtain quotes from multiple certified installers and consider life-cycle savings—higher upfront costs for a higher-performing system can yield lower energy bills and greater comfort over time.
Conclusion
Choosing a thermal barrier requires weighing material conductivity, installation quality, location-specific needs (attic, cavity, cladding), and how retrofit steps like draftproofing and air sealing will improve real-world performance. Use the table above as a starting point to compare product features and likely costs, then prioritize airtightness and continuous insulation strategies to maximize energy efficiency, comfort, and long-term savings.
