Rock Wool Insulation vs Glass Wool Insulation – What is the Difference

From insulating industrial pipelines and cinema walls to insulating ceilings and walls in residential complexes, rock wool and glass wool insulation materials come out on top. Although they are distinct insulation materials, they share a multitude of impressive traits, making them a darling among architects, HVAC engineers, and contractors.

But what do you know about them? Read along to find out.

What is Rock Wool Insulation?

Rock wool insulation is a distinct material comprised of either dolomite or basalt and recycled elements that allows it to block the transfer of heat between two mediums. The inclusion of volcanic rocks in its composition contributes to its exceptional fire resistance. These rocks only melt at around 1,600 °C, making rock wool the perfect insulation for walls or components exposed to flames and high heat.

What is Glass Wool Insulation?

Glass wool insulation, conversely, is a fibrous insulation material with an R-value of between 2.2 and 2.7 that typically comes as rigid boards or flexible rolls, making it the perfect fit for cavity walls and lofts. Furthermore, it doubles up as an excellent acoustic insulator, making it ideal for insulating walls, roofs, and floors in noise-sensitive spaces such as cinemas and office complexes.

Key Differences Between Rock Wool and Glass Wool Insulation

The vast majority of insulators being utilized in industries, homes, and commercial spaces are either made from rock wool or glass wool. This is a testament to the great insulation properties that these distinct materials possess. However, they are different in several ways, most of which are discussed below;

· R Value

This value gauges an insulator’s ability to block the exchange of heat, and rock wool insulators are slightly superior compared to their glass wool counterparts. They boast an R-value of approximately 3.0 to 3.3 per inch, while the latter comes with an R-value of approximately 2.2 to 2.7.  This means that rock wool insulation guarantees greater resistance against heat loss or heat gain.

· Sound Insulation

Rock wool is comparatively denser, thanks to its thicker core made up of volcanic rocks. This means that it blocks the transmission of sound between media more effectively, making it the ideal acoustic and thermal insulator for applications prioritizing silence, such as music studios. Glass wool, in contrast, demonstrates great acoustic insulation. However, it is not quite as effective as rock wool since it is relatively less dense.

· Density

The average density or thickness of rock wool is approximately 1.8 pounds per cubic foot, making it significantly thicker than glass wool. As a result, it boasts greater compressive strength and fire resistance properties, making it ideal for relatively demanding applications such as pipeline insulation. The average density of glass wool insulation stands at approximately 0.5-1.0 pounds per cubic foot.

· Compressive Strength

Rock wool thrives in insulation installations demanding greater compressive strength, such as residential floors and industrial flat roofs, because it boasts up to 200kg in density. This means that the rock wool insulation products installed in such scenarios can withstand enormous loads without breaking. Compared to glass wool insulation products, this is significantly higher, given that their density is approximately 110 kg.

· Water Resistance

Glass wool insulation ideally necessitates a vapor barrier for it to work flawlessly in moisture-prone settings such as bathrooms. This is because moisture penetrates the spaces between the glass fibers, consequently diluting its insulation strengths.

Rock wool, on the other hand, suits perfectly humid bathrooms and even basements since it is hydrophobic. You can install it in your bathroom walls, ceiling, or floor without having to worry about reduced thermal insulation or the growth of molds.

· Fire Resistance

High-density rock wool insulators double up as excellent fire-retardants, qualifying their use in high-temperature applications such as kitchen and furnace insulation. Thanks to its high density, rock wool insulation can withstand temperatures as high as 700°C. Fiberglass insulation, in contrast, degrades much more quickly when subjected to high temperatures, particularly temperatures exceeding 400°C. This limits its use to low-temperature applications such as air conditioning ducts and ceiling insulation.

· Cost

Although the price of both rock wool and glass wool insulation products depends largely on availability, glass wool is quite often the cheaper option. In fact, you can buy glass wool insulation products at approximately 25%-50% of the price of rock wool. This is because its raw materials are generally more accessible, cost less, and are less dense.

· Weight

Fiberglass insulation, compared to rock or mineral wool insulation, weighs significantly less. This makes it ideal for structures or components that may crumble when subjected to great force. This makes installing fiberglass insulation products much easier. However, it disqualifies their use in structures where they will be subjected to heavy loads. In contrast, mineral wool is much heavier owing to its volcanic rock core and relatively higher density.

· Environmental Impact

The unwavering adoration accorded to fiberglass and rock wool insulation products is partly down to their eco-friendliness. They are both made from environmentally-friendly raw materials, some of which are products of recycling, making their use a step in the right direction regarding sustainability.

Comparing the Distinct Applications of Rock Wool and Glass Wool Insulation

Having looked at the distinct properties demonstrated by rock wool and glass wool insulation products, it is quite evident that each insulation product is designed for particular applications. The table below compares their respective uses.

Rock Wool Vs Glass Wool Insulation: Finding the Right Insulation for You

Rock wool and glass wool insulation, as impressive as each is in its respective rights, are built for distinct uses. Rock wool, thanks to its comparatively higher density and compressive strength, suits better demanding applications, whereas glass wool thrives better in applications necessitating flexibility and budget-friendliness.

Here is a table summarizing the respective use scenarios favored by each insulation product:

FAQs

Is rock wool a better thermal insulator than glass wool?

Yes. Rock wool boasts an R value of around 3.0 to 3.3, meaning it is more effective at blocking the exchange of heat between mediums. Glass wool, in contrast, records a maximum R value of around 2.7, meaning it is not as efficient as rock wool when it comes to thermal insulation.

Which is the healthier insulation, rock wool or glass wool?

Both rock wool and glass wool are considered healthy insulation options, meaning you can deploy them in your home or workplace without putting your health at risk. They both boast excellent moisture resistance, consequently minimizing the risk of bacterial or mold growth.

Does glass wool last longer than rock wool insulation?

No. Whereas glass wool is quite durable, it hardly outlives mineral wool insulation. Rock wool insulation products have an average lifespan of over 70 years, thanks to their relatively stiffer construction and great compressive strength. Glass wool, in contrast, averages a lifespan of around 55 years.

Is rock wool insulation water-resistant?

Yes. In fact, it is hydrophobic, meaning you can utilize it to insulate structures or components in humid environments, such as bathroom walls and ship components. This high degree of moisture-resistance makes rock wool insulation immune to mold growth, consequently qualifying it as a safe and healthy insulation product.

Between rock wool and fiberglass insulation, which is the best for external walls?

Rock wool suits better external walls, since it is hydrophobic, denser, and stronger. It can withstand physical impact and continuous exposure to moisture without swelling or losing its insulation properties.

Lutonpanel; Your Sandwich Panel Manufacturer in China

Whether you are looking for rock wool insulation or glass wool insulation panels, Lutonpanel is your trusted manufacturer in China. At Lutonpanel, we customize very panel to match your unique project’s needs and requirements.

Partner with us today, for all your custom-made insulation panels – talk to our sales team now.