You’ll need to make sure that the materials and tools that you are using for your insulation are the best that they can be, and that you’re using the right materials for the task at hand. Fibreglass and mineral wool are two of the best materials to use, but which is better for different scenarios?
What is glass wool insulation?
Glass wool insulation is also sometimes referred to as fibreglass, which makes sense considering it is literally made from glass fibres. To create it, glass is heated up to extremely high temperatures until it reaches a melting point, then is quickly spun to create glass fibres. The fibres are bound together to be used as an insulation material.
The way it works is to use the pockets of air that act as a barrier to make sure that heat does not escape. Glass wool is used in a variety of ways including within insulation boards, in batts and rolls and loose-fill insulation.
What is mineral wool insulation?
Mineral wool insulation is also referred to as stone wool or rock wool. It is made from a range of raw materials like rock and stone, and the process for this is very similar to the earlier description of the glass wool insulation process. The materials are melted at a high temperature again before being spun to form fibres. The mineral wool is then usually packed into either slabs, rolls, or batts.
Which is more sustainable?
If sustainability is your main consideration, then it’s likely glass wool that’s the best option for you. This is because it is made up of around 85% recycled materials, compared to the around 70% for mineral wool. This means that glass wool tends to be the better option for less of an environmental impact.
Which is better for blocking out sound?
If you live in a noisy area and are often disrupted by loud noises coming from outside the house, then mineral wool is the better option for blocking sound from travelling through your walls and floors, as it is a much denser material than glass wool. It also helps prevent sound from leaving your home and disturbing your neighbours, which could be important if you have a drum kit or a guitar and need extra soundproofing, for example. If this is a big issue, there are plenty of specific acoustic insulation products available.
What are the R-values of glass wool and mineral wool?
An R-value relates to a material’s ability to resist heat following through it at a certain thickness. The higher the R-value, the better it can resist heat transfer. When comparing the R-values of glass wool and mineral wool insulation, they both tend to have a thermal conductivity of around 0.044W/mK, so they are very similar in this regard.


Which one is easier to install?
As it tends to be a lot easier to cut and fit into place, mineral wool is usually considered to be easier to install, which is important if you’re undertaking the task yourself rather than calling in a professional to help. Mineral wool is heavier and fits into place easier, while glass wool tends to be difficult to fit into certain spaces when you need it to.
Which is cheaper?
It will depend on the exact product and brand that you go with, but glass wool is often cheaper than mineral wool by around 10%, give or take. Therefore, if you’re working on a strict budget then the cheaper glass wool may be the one to go for.
Which is more fire resistant?
It goes without saying that you want your chosen insulation product to be as fire resistant as possible, and both options are non-combustible. That being said, mineral wool has far better fire-resistant qualities and can even be used as a fire-stop. So, if ensuring your home is as fire-resistant as possible is top of your priority list, then mineral wool will be the choice.
Which is more damp resistant?
Moisture can form and cause a lot of damage to a property if not looked after properly, and mineral wool is certainly the more damp-resistant of the two. It has a natural resistance to water and doesn’t get damp. This is not true of glass wool, which can get wet, which reduces its insulating properties.
What are the main benefits of glass wool insulation?
- It tends to be cheaper
- It is more sustainable and has less of an impact on the environment
- It can reduce your energy bills
What are the main benefits of mineral wool insulation?
- It’s very easy to install
- It’s very fire and damp resistant
- It is denser than glass wool, therefore works better as a soundproof acoustic insulation option
- It can reduce your energy bills