Aerolite vs Isotherm
Aerolite vs Isotherm Insulation – Which Is Better?
If you’re comparing Aerolite vs Isotherm insulation, you’re looking at two commonly used ceiling insulation options in South Africa:
- Aerolite Soft Touch – glasswool insulation
- Isotherm – polyester insulation
Both products are used in residential and commercial buildings, but they differ significantly in performance, material properties, and overall value.
You can also explore all our insulation comparisons to compare different materials, brands, and applications.
Here’s how Aerolite and Isotherm insulation compare, including performance, pricing, and which option is better for your home.
Quick Answer
- Best overall performance: Aerolite
- Best thermal efficiency: Aerolite
- Best fire resistance: Aerolite (A1 non-combustible)
- Best acoustic (noise dampening): Aerolite
- Best comfort (soft to handle): Isotherm
Both products work, but Aerolite offers higher performance across all categories, while Isotherm focuses more on comfort and ease of handling.
Aerolite vs Isotherm Comparison
| Feature |
135mm Aerolite
|
145mm Isotherm
|
|---|---|---|
| Material | Glass mineral wool | Polyester |
| Thermal Performance | High (R-value ±3.38) | Moderate (R-value ±3.37) |
| Fire Rating | Non-combustible (A1) | Combustible (B-class) |
| Acoustic Performance | Excellent | Moderate |
| Density | Higher (±11kg/m³) | Lower (±11kg/m³) |
| Comfort (handling) | Soft-touch (low itch) | Very soft, non-itch |
| Lifespan | Long-lasting and stable | Can compress slightly over time |
| Typical Price Range | ±R599 per roll |  ±R699 per roll |
Thermal Performance
Aerolite provides strong thermal performance with an R-value of around 3.38 for 135mm thickness.
Isotherm also provides insulation, but typically delivers lower thermal performance due to its material structure and density.
In real-world applications, Aerolite performs better at maintaining indoor temperature.
Fire Safety
There is a major difference here:
- Aerolite = A1 fire rating (non-combustible)
- Isotherm = B-class (combustible under certain conditions)
A1-rated insulation does not burn or contribute to fire spread, making it a significantly safer option. Aerolite offers a much higher level of fire safety.
If fire resistance is critical, you can also explore our fire-rated insulation products for higher-spec applications.
Acoustic Performance
Aerolite performs well in reducing noise due to its fibrous glasswool structure and higher density.
Isotherm still provides sound absorption, but typically not to the same level.
For noise reduction and soundproofing, Aerolite is the much better option.
Price and Value
Pricing can vary depending on supplier, but typically:
- Aerolite: ±R599 per roll (covers ±6m²)
- Isotherm: ±R699 per roll (covers ±6m²)
When comparing value:
- Aerolite offers higher performance
- Isotherm often costs more
Aerolite provides better overall value per m²
Real-World Recommendation
Choose Aerolite if:
- You want better thermal performance
- You want non-combustible insulation
- You want stronger acoustic performance
- You want better value for money
Choose Isotherm if:
- You prefer a completely non-itch material
- Comfort during installation is your main priority
Final Verdict
Both Aerolite and Isotherm are widely used insulation products.
However:
- Aerolite offers higher thermal performance
- Aerolite is non-combustible (A1 rated)
- Aerolite provides better acoustic insulation
- Aerolite offers better value for money
For most homes, Aerolite is the better overall insulation choice
Best overall:
Aerolite Insulation
Alternative option:
Isotherm Insulation
Compare Aerolite vs Isotherm Insulation Options
What To Do Next
-
- View Aerolite insulation prices
- View Isotherm insulation prices
- Shop ceiling insulation
- Shop roof insulation
- Browse glasswool insulation
- Browse polyester insulation