In 2026, China's construction industry will be fully adapted to the "dual carbon" targets of "peak carbon dioxide emissions" by 2030 and "carbon neutrality" by 2060, with a focus on energy conservation through exterior wall insulation. Industry reports by China Building Energy Conservation Association and other related associations reveal that "over 35% of total building energy conservation investments" come from "exterior wall insulation." The selection of good quality exterior wall insulation materials will directly affect "carbon dioxide emissions" during the building's lifecycle. "Insufficient building insulation will increase building energy consumption by 30-50%." On the other hand, good building insulation will greatly reduce a building's "carbon footprint" and achieve "green building" certifications like LEED or China Green Building Evaluation Standard.

United Insulation, a professional supplier of glass wool and rock wool, dedicated to exporting related products, bases our service on our experience serving international projects and our knowledge of related standards, including GB/T 25975-2020 "Rock Wool Products for External Wall Insulation Systems" and GB/T 17738-2022 "Glass Wool Products." Here, you can compare "Rock Wool Boards" and "Glass Wool Boards" side by side, which are two of the best "Class A Fire-Resistant" materials.

I. Quick Overview: Rock Wool Boards and Glass Wool Boards

Rock Wool Boards: Mainly composed of basalt, melted and spun into rough, stiff fibers. The rock wool boards exported by us have a density of 80-150 kg/m³, an acidity coefficient of ≥1.6, and good corrosion resistance, which are suitable for external wall insulation of high-rise buildings.

Glass Wool Boards: Made of molten silica sand and borax, spun into fine, long, and soft fibers. The density of glass wool boards ranges from 24-96 kg/m³, with a fiber diameter of 5-8 micrometers, and good moisture resistance, which are suitable for low- to mid-rise buildings or where weight is a concern.

Both rock wool and glass wool are inorganic fiber insulation materials that are green, environmentally friendly, formaldehyde-free, and have low VOCs, and their production process complies with REACH environmental regulations, which helps reduce carbon dioxide emission in buildings during use and is beneficial to the protection of the natural environment.

II. Core Performance Comparison (data source: GB 8624-2012, GB/T 10295-2021, and industry reports for 2025-2026).

Table below shows the latest actual parameters (average temperature 25℃, in accordance with national standards and industry test reports):

Thermal performance is an important characteristic of exterior wall insulation materials with respect to their efficiency. The glass wool boards have an excellent grade with a thermal conductivity of ≤0.035. The material allows 10-20% thinner layers to have the same R value. This helps reduce material usage and carbon emissions during transportation. The rock wool boards have a slightly higher rate of thermal conductivity. However, they have better stability and can be used in areas with extreme cold conditions and temperature fluctuations.

Fire resistance: Both materials have Class A non-combustibility (GB 8624). The rock wool boards have the highest rating, Class A1. It has a fire resistance period longer than 4 hours and does not produce toxic fumes. According to a 2025-2026 report on the industry, fire resistance ratings are becoming increasingly stringent for exterior wall insulation materials in exterior walls of high-rise buildings. This again supports the use of rock wool boards as Class A fire-resistant exterior wall insulation materials.

Water absorption and durability: The glass wool material resists water absorption better. It is a suitable environmentally friendly material for exterior wall insulation in hot southern climates. The rock wool material has excellent durability and long service life. This helps reduce waste and carbon emissions during replacements.

III. Deep Connection with Ecological Protection: How External Wall Insulation Can Support the "Dual Carbon" Goal

Among all building carbon reduction measures, external wall insulation is the most direct approach to reducing carbon emissions. Research carried out by the China Academy of Building Research, as well as the 14th Five-Year Plan on low carbon exterior wall insulation systems, indicates that high-quality insulation materials can reduce building operating energy consumption by 30-50%, which is equivalent to reducing CO₂ emissions by 15-30 kg per square meter of exterior wall per year. The Life Cycle Assessment (LCA) indicates that:

- The carbon footprint of glass wool board is low, with some adhesives used in the manufacturing process having low carbon emissions. The recyclability of glass wool is high, with up to 84% recyclability. The energy-saving effect is significant. For example, an exterior wall system consisting of an 80mm glass wool board is used in buildings located in hot summer, cold winter zones. The building's energy consumption is reduced by 35%, which is equivalent to planting 10-15 trees per year.

- The carbon footprint of rock wool board is also low, with about 70% of the raw materials used in manufacturing having come from recycled slag. The durability of the material is high, with an expected lifespan of over 50 years. The carbon footprint reduction effect is significant. For example, high-rise buildings using rock wool exterior wall insulation systems meet fire resistance and energy-saving standards. The carbon emission reduction efficiency is over 40% as indicated in the report published in 2026.

In addition, the use of low carbon exterior wall insulation materials not only meets the EU REACH and China's dual carbon goals but also enables projects to qualify for subsidies. The ISO 14001:2015 Environmental Management System Certification ensures that United Insulation's products are reliable, energy-saving, and environmentally friendly.

IV. 2026 Typical Application Material Selection Guide for Exterior Wall Insulation

1.High-rise buildings, public buildings, etc. (Fire resistance priority): Use rock wool board for exterior wall insulation, with A1 grade long fire resistance. The recommended thickness is 80-120mm, which meets GB 50016 standards for high-rise building fire protection.

2.Mid- and low-rise residential buildings, villas, etc. (Energy saving and cost-effectiveness): Choose glass wool board with low thermal conductivity, light weight, and faster construction speed, with a recommended thickness of 60-100mm.

3.Hot and humid regions, coastal areas, etc.: Glass wool board has better water repellency and anti-condensation performance.

4.Extremely cold regions: Rock wool board has better density and stability, and can be combined with thin-plaster exterior wall systems.

5.Green building certification: Both materials are qualified, but choose rock wool board with better durability based on life cycle assessment results to achieve greater carbon reduction benefits.

V. Frequently Asked Questions (FAQs)

FAQ1: In 2026, is rock wool board or glass wool board more environmentally friendly for exterior wall insulation?

Both materials are green, formaldehyde-free, and low-VOC. Glass wool board has a slightly better carbon footprint and recycling performance, while rock wool board has stronger durability, higher recycled slag content, and greater carbon reduction benefits. For low-carbon exterior wall insulation, choose a material based on fire protection requirements and climate regions, as they will greatly affect the "dual carbon" goal.

FAQ2: Under Class A fire resistance requirements, which is more worthwhile to buy, rock wool board or glass wool board?

Rock wool board, with Class A1 fire resistance rating and longer fire resistance, is a must-have for high-rise buildings. If you are building a mid- or low-rise building or have a budget constraint, Class A non-combustible glass wool board with low thermal conductivity is your best choice. United Insulation also offers free thermal calculations and free fire safety reports.

FAQ3: How to choose the thickness of an exterior wall insulation system to maximize energy saving and carbon reduction?

Different climate zones have different energy-saving standards. In hot summer/cold winter zones, you should use ≥70mm; in frigid zones, you should use ≥100mm. With glass wool board, you can also reduce thickness by 10-20% while still achieving the same thermal resistance. In fact, studies have also shown that adding 20mm thickness to glass wool board can lead to a 10-15% reduction in carbon emissions, but you have to weigh the costs.

Conclusion:

Rock wool boards are excellent materials with top-class fire resistance and durability, while glass wool boards are excellent materials with low thermal conductivity, light weight, and cost-effectiveness. In 2026, selecting the right exterior insulation materials is not only about energy savings and cost savings, but also about ecological responsibility.

United Insulation (www.unitedinsulation.com) is a leading insulation supplier of export-grade rock wool boards and glass wool boards with stable product specifications and full product certifications, with successful cases of low-carbon exterior wall insulation in the Middle East, Southeast Asia, Europe, and other countries. We now have 2026 product samples, data, LCA, and free consultation on selecting materials, so please don't hesitate to contact us to work together to drive the green building industry forward.