Elastomeric vs Mineral Wool — Which Is Best?
Elastomeric vs Mineral Wool — Which Is Best?
A Professional Comparison for HVAC, Refrigeration & Commercial Pipe Insulation
Choosing between elastomeric and mineral wool insulation is one of the most important decisions for any HVAC or refrigeration project. Both materials have distinct advantages, and the right choice depends on your application, temperature range, and installation environment.
This guide compares the two materials side-by-side to help you make the best decision for your project.
📊 Quick Comparison Table
| Feature | Elastomeric (K-FLEX ST/SK) | Mineral Wool (K-Rock) |
|---|---|---|
| Material Type | Closed-cell synthetic rubber | Stone wool fibres |
| Temperature Range | -50°C to +105°C (Solar HT: +150°C) | -40°C to +250°C |
| Moisture Resistance | Excellent (closed-cell structure) | Requires vapour barrier |
| Fire Rating | Class O / Class 1 | Non-combustible (A1/A2) |
| Installation | Fast, flexible, self-seal options | Rigid sections, requires cladding |
| Best For | Chilled water, refrigeration, HVAC | High-temp steam, fire-critical areas |
| Condensation Control | Excellent (built-in vapour barrier) | Requires external vapour barrier |
| Cost | Mid-range | Higher (inc. cladding & labour) |
✅ When to Choose Elastomeric (K-FLEX ST/SK/PE)
👍 Best Applications:
- Chilled water systems (6-12°C)
- Refrigeration lines (-30 to +10°C)
- Heat pump pipework
- HVAC heating & cooling (up to 105°C)
- Domestic hot & cold water
- Condensation-prone environments
⭐ Key Advantages:
- ✅ Built-in vapour barrier — No need for additional wrapping
- ✅ Fast installation — Flexible tubes, self-seal options (SK range)
- ✅ Excellent condensation control — Closed-cell structure prevents moisture ingress
- ✅ Lightweight and flexible — Easy to handle and fit around bends
- ✅ No cladding required (for most applications)
⚠️ Limitations:
- ❌ Not suitable for very high temperatures (>105°C, except Solar HT)
- ❌ Not non-combustible (use mineral wool for fire-critical areas)
🔥 When to Choose Mineral Wool (K-Rock)
👍 Best Applications:
- High-temperature steam lines (100-250°C)
- Fire-critical plant rooms
- Commercial risers requiring non-combustible insulation
- Industrial heating systems
- Building Regulation compliance (fire safety)
⭐ Key Advantages:
- ✅ Non-combustible — A1/A2 fire rating
- ✅ High-temperature performance — Up to 250°C
- ✅ Excellent thermal efficiency
- ✅ Ideal for fire-critical areas (plant rooms, risers)
⚠️ Limitations:
- ❌ Requires vapour barrier for cold applications
- ❌ Rigid sections — Slower installation than elastomeric
- ❌ Needs protective cladding (aluminium or PVC)
- ❌ Higher total cost (material + labour + cladding)
🤔 Which Should You Choose?
👉 Choose Elastomeric (K-FLEX) if:
- You're insulating chilled water, refrigeration, or HVAC systems
- Condensation control is critical
- You want fast, flexible installation
- Temperature range is -50°C to +105°C
- Fire rating Class O/1 is acceptable
👉 Choose Mineral Wool (K-Rock) if:
- You're insulating high-temperature steam or heating systems (>105°C)
- Non-combustible insulation is required (fire regulations)
- You're working in fire-critical plant rooms or commercial risers
- Building Regulations specify A1/A2 fire rating
📚 Related Guides
- Insulation Thickness Selection Guide
- Dew Point & Condensation Explained
- K-FLEX Premium Range Overview
- Back to Knowledge Centre
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Need help choosing? Contact our technical team for project-specific advice.