Thermal vs. Acoustic Insulation: What’s Best for Your Build?

By CB Building Products – Your UK Thermal and Acoustic Insulation Supplier

Choosing the right insulation is one of the most important decisions during any build or renovation. Whether you’re working on a home loft conversion, commercial office fit-out, or new build, you’ll need to consider both temperature control and soundproofing.

As a leading thermal insulation supplier and stockist of acoustic insulation, we’re here to help you make an informed decision. In this guide, we’ll compare both types of insulation, explore their benefits, and help you decide which is best suited to your project.

What Is Thermal Insulation?

Thermal insulation helps control indoor temperature by reducing heat transfer. It keeps heat in during winter and out during summer. This not only improves comfort but also reduces energy bills and carbon emissions.

Key materials include:

• PIR rigid boards.
• Mineral wool.
• Foil-backed insulation rolls.
• Expanded polystyrene.

Best suited for:

• Loft insulation in UK homes.
• Wall and roof insulation in domestic and commercial builds.
• Floors and underfloor heating systems.

Thermal insulation is regulated under UK Building Regulations (Part L), meaning you’ll need to meet specific U-values depending on the area of the building.

 

Key Differences at a Glance

Feature	Thermal Insulation	Acoustic Insulation
Purpose	Controls heat transfer	Reduces noise transfer
Common Areas	Lofts, walls, roofs, floors	Partitions, ceilings, floors
Key Materials	PIR, mineral wool, EPS, natural fibres	High-density wool, plasterboard, acoustic mats
Measured By	U-values and R-values	Sound Transmission Class (STC), Decibels (dB)
Building Regulations	Part L (thermal performance)	Part E (soundproofing for dwellings)

 

When to Use Thermal Insulation

Choose thermal insulation when your goal is energy efficiency, comfort, and meeting regulatory targets for heat retention.

Common use cases include:

• Loft conversions where heat escapes rapidly.
• External wall insulation on new builds.
• Flat and pitched roof insulation.
• Underfloor insulation to support heating systems.

If you’re targeting lower energy bills and increased EPC ratings, this is your go-to solution.

Can You Combine Thermal and Acoustic Insulation?

Yes – and in many cases, you should. Certain products are designed to offer both thermal and acoustic benefits, especially high-density mineral wool.

At CB Building Products, we can recommend dual-performance solutions that reduce heat loss and block out sound without sacrificing performance in either area.

Examples of combined applications:

• Drylining systems using dense mineral wool slabs.
• Partition walls using acoustic plasterboard and thermal liners.
• Roof and loft builds using multi-layer insulation systems.

 

FAQs: Helping You Choose

Which insulation should I use for an office?
Use acoustic insulation to reduce sound transfer between partitions. For roof or wall areas, combine with thermal insulation to control temperature.

What’s best for a loft conversion?
A mix of both. Use thermal insulation for roof slopes and walls, and acoustic insulation for partitions or separating floors.

Can I just use thermal insulation in a wall?
You can, but if the wall is between rooms or buildings, you may also need soundproofing to meet Part E regulations.

Is acoustic insulation more expensive?
It depends on the product. High-density materials often cost more but are essential for proper sound attenuation. We can advise based on your budget and spec.

Do you offer advice on specification?
Yes. As a trusted thermal insulation supplier and acoustic expert, we offer free guidance to help match products with your building requirements.