Understanding R-Values in Insulation: R2.0 to R7.0 Explained for Adelaide Homes

Understanding R-Values in Insulation: R2.0 to R7.0 Explained for Adelaide Homes

If you’ve been shopping for insulation in Adelaide, you’ve probably seen terms like R2.5, R4.0 or R6.0 on packaging and product pages. But what do those numbers actually mean?

This guide breaks down everything you need to know about R-values — how they work, why they matter, and which R-value is best suited to Adelaide’s climate.

What is an R-Value?

The R-value is a measure of thermal resistance — in simple terms, how well the insulation resists heat flow. The higher the R-value, the better the insulation is at keeping heat out in summer and in during winter.

Here’s a quick breakdown:

  • Low R-values (R1.5–R2.5): Suitable for mild climates or specific zones like walls and underfloor areas.
  • Medium R-values (R3.5–R4.0): Ideal for standard ceilings in most Adelaide homes.
  • High R-values (R5.0–R7.0): Best for energy-efficient homes or extreme weather protection.

What’s the Best R-Value for Adelaide Homes?

Adelaide experiences hot summers and cool winters, so well-balanced insulation is key. The South Australian government recommends:

  • Ceilings: R4.0 to R6.0
  • Walls: R2.0 to R2.7
  • Underfloors: R2.5

You can browse our full range of Earthwool products by R-value:

Do Higher R-Values Always Mean Better Performance?

Higher R-values generally provide better thermal resistance, but they also cost more and may require more installation space. The key is choosing the right R-value for each part of your home:

  • Ceiling spaces: Go for at least R4.0 — higher if you want better energy efficiency.
  • Walls: R2.0–R2.7 is usually enough for Adelaide conditions.
  • Underfloor: Use R2.5 batts like our Earthwool FloorShield.

How to Choose the Right Product

It’s not just about R-value — also consider:

  • Density (kg/m³): Higher density products like Earthwool 14kg/m³ offer better soundproofing and fit tighter in wall cavities.
  • Application: Ceiling, wall, or underfloor insulation all require different types of batts.
  • Size of your space: Measure your square metre coverage needs carefully before ordering.

Still Unsure? We Can Help

If you're unsure which R-value is right for your Adelaide home, reach out to our team. We’ll help you choose the right combination of performance and price — whether you’re building new, renovating, or retrofitting insulation into an existing property.

Shop our full range of Earthwool insulation products today and get fast, affordable delivery across South Australia.

Back to blog