Multifoil vs Mineral Wool: Which Insulation Is Right for Your Home?
Comparing the UK's two most popular loft insulation types to help you choose the best option for your property.
Choosing the Right Insulation
When it comes to loft insulation, two options dominate the UK market: traditional mineral wool rolls and modern multifoil insulation. Both have their strengths, and the right choice depends on your specific situation.
Mineral Wool
How It Works
Mineral wool traps millions of tiny air pockets within its fibrous structure, resisting heat transfer and keeping warmth in your living spaces.
Pros
- Proven track record in millions of UK homes
- Most cost-effective option per square metre
- Easy to install between joists
- Fire-resistant and non-combustible
- Excellent acoustic properties
- No mortgage concerns — universally accepted
Cons
- Requires 270mm depth for recommended performance
- Absorbs moisture if it gets wet
- Irritant fibres during installation
- Limits loft storage space
Multifoil Insulation
How It Works
Multiple layers of reflective foil separated by wadding reflect radiant heat back towards its source, while internal layers provide additional thermal resistance.
Pros
- Slim profile (25-40mm) preserves loft space
- Lightweight and clean to install
- Moisture resistant
- Ideal for loft conversions where headroom is limited
- Doesn't compress or degrade over time
Cons
- Higher cost per square metre
- Requires air gaps to work effectively
- Installation technique matters more
- Shorter track record in the UK
Head-to-Head
Cost: Mineral wool wins — £300-£600 vs £500-£1,000 for a typical 3-bed semi.
Space: Multifoil wins — 25-40mm vs 270mm thickness.
Installation: Mineral wool is more forgiving of imperfect installation.
Longevity: Multifoil maintains performance longer without maintenance.
Which Should You Choose?
Choose mineral wool if budget is key, you have good loft headroom, and want a proven solution. Choose multifoil if space is limited, you're doing a loft conversion, or long-term performance matters most.
Consider combining both — mineral wool between joists topped with multifoil gives excellent thermal performance plus a flat surface for lightweight storage.
A free loft assessment can evaluate your specific situation and recommend the most effective solution for your home.