Home Insulation Materials Comparison

Compare thermal performance, costs, fire safety and environmental impact of different insulation materials

About Insulation Materials

Choosing the right insulation material is crucial for energy efficiency, comfort, and long-term performance. Different materials offer varying thermal properties, installation methods, environmental benefits, and cost considerations.

Best Performers

Best Thermal

Phenolic Foam

Most Cost-Effective

Cellulose

Most Eco-Friendly

Cellulose

Best Fire Rating

Cellulose

Material Performance & Cost Comparison

Cellulose

Fibrous

Made from recycled newspaper and cardboard, cellulose is an eco-friendly option treated with fire retardants. Popular for loft insulation and cavity filling.

Key Benefits

  • R-value: 3.6 per inch
  • Good (Treated) fire resistance
  • Lifespan: 30+ years
  • Recyclable material

Performance Ratings

Fire Rating
Good (Treated)
Moisture Resistance
Fair
Eco-Friendliness
Excellent

Thermal Conductivity

0.039 W/m·K

Cost per m²

£2.80

R-Value

R-3.6

Made from recycled glass or volcanic rock, mineral wool is one of the most popular insulation materials in the UK due to its excellent thermal performance and fire resistance.

Key Benefits

  • R-value: 4.2 per inch
  • Excellent (Non-combustible) fire resistance
  • Lifespan: 50+ years
  • Recyclable material

Performance Ratings

Fire Rating
Excellent (Non-combustible)
Moisture Resistance
Good
Eco-Friendliness
Good

Thermal Conductivity

0.034 W/m·K

Cost per m²

£3.50

R-Value

R-4.2

Lightweight foam boards made from expanded polystyrene beads. Popular for external wall insulation systems due to good insulation properties and affordability.

Key Benefits

  • R-value: 3.8 per inch
  • Fair (Combustible) fire resistance
  • Lifespan: 50+ years
  • Recyclable material

Performance Ratings

Fire Rating
Fair (Combustible)
Moisture Resistance
Excellent
Eco-Friendliness
Fair

Thermal Conductivity

0.037 W/m·K

Cost per m²

£4.20

R-Value

R-3.8

Reflective Foil

Reflective

Multi-layer reflective insulation that works by reflecting radiant heat. Most effective in hot climates or for reducing summer heat gain.

Key Benefits

  • R-value: 2.5 per inch
  • Good fire resistance
  • Lifespan: 20+ years
  • Recyclable material

Performance Ratings

Fire Rating
Good
Moisture Resistance
Excellent
Eco-Friendliness
Good

Thermal Conductivity

0.045 W/m·K

Cost per m²

£6.50

R-Value

R-2.5

High-performance foam insulation available as spray-applied or rigid boards. Excellent thermal performance and air sealing properties make it ideal for difficult-to-insulate areas.

Key Benefits

  • R-value: 6.0 per inch
  • Fair (Combustible) fire resistance
  • Lifespan: 25+ years

Performance Ratings

Fire Rating
Fair (Combustible)
Moisture Resistance
Excellent
Eco-Friendliness
Fair

Thermal Conductivity

0.025 W/m·K

Cost per m²

£8.50

R-Value

R-6.0

Natural wool fiber insulation offering excellent thermal performance with moisture-regulating properties. Sustainable and safe option for environmentally conscious homeowners.

Key Benefits

  • R-value: 3.8 per inch
  • Good (Naturally fire retardant) fire resistance
  • Lifespan: 50+ years
  • Recyclable material

Performance Ratings

Fire Rating
Good (Naturally fire retardant)
Moisture Resistance
Excellent
Eco-Friendliness
Excellent

Thermal Conductivity

0.038 W/m·K

Cost per m²

£12.00

R-Value

R-3.8

High-performance rigid foam boards with excellent thermal properties and fire resistance. Often used where space is limited and maximum insulation is needed.

Key Benefits

  • R-value: 7.0 per inch
  • Excellent (Self-extinguishing) fire resistance
  • Lifespan: 30+ years

Performance Ratings

Fire Rating
Excellent (Self-extinguishing)
Moisture Resistance
Good
Eco-Friendliness
Fair

Thermal Conductivity

0.022 W/m·K

Cost per m²

£15.50

R-Value

R-7.0

Insulation Material Categories

Fibrous Materials

Made from glass or rock fibers. Excellent thermal performance, fire resistance, and sound absorption. Popular choices include mineral wool and fiberglass.

Foam Materials

Expanding foams that create air-tight seals. Superior thermal performance and moisture barriers. Includes spray foam and rigid foam boards.

Natural Materials

Eco-friendly options from renewable sources. Breathable, moisture-regulating properties. Includes sheep wool, cellulose, and cork.

Reflective Materials

Radiant barriers that reflect heat. Effective in hot climates and roof applications. Often combined with other insulation types.

Need Help Choosing the Right Insulation Material?

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