Two quotes for “the same” insulation can differ by 40% — and neither supplier is lying. Rock wool and fibreglass (glass wool) are priced on completely different numbers: density, thickness, form, facing, and how much air you are shipping in the container. This guide breaks down what actually drives the price so you can compare quotations line by line instead of comparing totals.
1. The five factors that decide your price
- Density (kg/m³) — the single biggest driver. Insulation is sold by weight at the factory gate, so a 100 kg/m³ board costs roughly three times a 32 kg/m³ product of the same volume. Rock wool boards normally run 60–200 kg/m³; glass wool rolls run 24–32 kg/m³.
- Thickness (mm) — cost scales almost linearly with thickness. 100 mm costs about twice 50 mm in the same density.
- Product form — a board, a strip, a felt blanket, a pipe section and a granulate can all be made from the same fibre, but cutting, moulding and packaging change the conversion cost. Pipe sections and machined strips carry the highest conversion premium.
- Facing and treatment — aluminium foil, black glass tissue, water-repellent (hydrophobic) treatment, or a factory-applied vapour barrier. A foil facing can add a measurable percentage to the unit price, and it changes the panels, glue and packing you need too.
- Order size and freight — insulation is bulky but relatively light, so you often pay for volume, not weight. A full 40HQ container spreads the same sea freight over far more square metres than an LCL trial order, and that difference frequently exceeds the product-price difference between two suppliers.
2. Cost per m²: the only comparison that matters
Price per tonne and price per m² are different questions. Convert everything to cost per square metre so quotes become comparable:
Cost per m² = price per kg × density (kg/m³) × thickness (mm) ÷ 1000
Worked example at an illustrative 0.50 USD/kg (ask us for today’s factory price):
| Product | Density | Thickness | Weight per m² | Illustrative cost per m² |
|---|---|---|---|---|
| Glass wool roll | 32 kg/m³ | 100 mm | 3.2 kg | ≈ 1.60 USD |
| Rock wool board | 80 kg/m³ | 100 mm | 8.0 kg | ≈ 4.00 USD |
| Rock wool board | 100 kg/m³ | 100 mm | 10.0 kg | ≈ 5.00 USD |
The pattern is consistent across markets: at the same thickness, glass wool is the cheaper square metre and rock wool is the heavier, more expensive one. The real question is whether the cheaper square metre is still acceptable once fire rating, rigidity, moisture and service life are taken into account.
3. Where the price difference pays back
- Fire-rated compartments. Rock wool is A1 non-combustible with a melting point above 1,000 °C and keeps its shape in a fire. For high-rise facades, escape routes, car parks and fire-rated ductwork it is normally the specified product — a cheaper glass wool fill that fails the fire test is the most expensive decision on the project.
- Rigidity and load. In ETICS facades, curtain walls, roof build-ups and sandwich panel cores, the board has to hold its own shape. 100–140 kg/m³ rock wool is structural in a way 32 kg/m³ glass wool is not.
- Moisture and condensation. Cold rooms, food plants, coastal and tropical projects: hydrophobic rock wool holds thermal performance when humidity is high, where lighter glass wool needs a well-detailed vapour barrier.
- High temperature. Pipe, tank and process insulation above roughly 250 °C belongs to rock wool (pipe sections, felt blankets), not to resin-bonded glass wool.
4. Cost by application
| Application | Typical product | Where the cost sits |
|---|---|---|
| Exterior wall / ETICS | Rock wool board 50–140 kg/m³ | Density and thickness; fixings and render add more than the board |
| Cold room / sandwich panel core | Stone wool strip 80–120 kg/m³ | Cut-to-size tolerance versus your panel line |
| Curtain wall / rainscreen | Curtain wall board 60–120 kg/m³ | Density plus facade certification |
| HVAC duct and ceiling | Glass wool roll / board 24–32 kg/m³ | Facing and roll length; freight dominates |
| Pipe, tank, plant | Pipe sections and felt blankets | Conversion cost — diameter and thickness combinations |
| Flat and metal roof | Roof board 100–150 kg/m³ | Compressive strength, water repellency |
5. Five checks that make two quotes comparable
- Verified density, not declared density. Ask for the batch test report for your production run. A “100 kg/m³” board that arrives at 82 kg/m³ is the most common hidden cost in the trade.
- Thickness tolerance and size tolerance. ±1 mm versus ±3 mm changes how the product performs on a facade system or a panel line.
- Facing named exactly. “Foil” is not a specification; the foil weight (gsm) and the glue system are.
- Packing and loading plan. Ask how many m² fit in a 40HQ at your thickness — the loading plan usually explains more of the price gap than the product does.
- Delivered terms. Compare FOB with FOB, or CIF with CIF including insurance. A quote that excludes packing, pallets, inland haulage or documentation is not a lower price.
6. What a CIF quotation should itemise
Product ex-works → packing and pallets → inland haulage to the port → export documentation (invoice, packing list, certificate of origin, test reports) → ocean freight and insurance. When you ask for a quotation, send the following and you will get a comparable number back the first time: product form, density, thickness, dimensions or pipe size, facing, quantity in m² or m³, destination port, and Incoterm.
Frequently asked questions
Is glass wool always cheaper than rock wool?
Per square metre at the same thickness, usually yes, because glass wool is much lighter — 24–32 kg/m³ against 60–200 kg/m³. Per square metre at the same fire rating, rigidity and moisture performance, the two products are often much closer than the headline prices suggest.
Why is a 40HQ container cheaper per m² than an LCL order?
Insulation ships mostly by volume. A full container spreads the fixed ocean freight, terminal charges and documentation over far more cubic metres, so the delivered cost per m² drops sharply. Trial orders are best used to qualify the product, then converted to container volume.
Can you supply a mixed container with several densities?
Yes. Our range covers 40–200 kg/m³ in boards, strips, felts, pipe sections and granulate, and mixed loading is normal for distributors who stock more than one application.
How do prices move over a year?
Watch basalt and slag raw material, binder and energy costs, plus ocean freight rates and container availability. Locking a volume with a validity window is usually cheaper than buying spot month by month.
Get a priced comparison for your project
Send us your specification and destination port and we will quote the product you actually need — with batch test reports, loading plan and delivered cost per m². Request a quotation, or browse the full product range first. WhatsApp +86 175 6050 1246. We reply within 24 hours.
Related reading
- Rock Wool vs Fiberglass Insulation: Complete Comparison
- Rock Wool Thermal Conductivity and R-Value Explained
- How to Import Rock Wool from China: A Complete 7-Step Guide
Sourcing by market
- Rock Wool Supplier for Indonesia
- Rock Wool Supplier for Thailand
- Rock Wool Supplier for Vietnam
- Rock Wool Supplier for the Philippines
- Rock Wool Supplier for Malaysia
- Rock Wool Supplier for Saudi Arabia
- Rock Wool Supplier for the UAE
- Singapore
6. How to compare two quotes fairly — a five-point checklist
- Density and thickness stated in kg/m³ and mm — never “standard”.
- λ value and the standard it was tested to, so you can convert to R-value yourself.
- Format and facing exactly as quoted (board / strip / blanket / pipe section, plain / foil / mesh).
- m³ per container and packing method, so you can compute landed cost per m³.
- MOQ, lead time, Incoterm and payment terms — FOB and CIF quotes are not comparable.
If a supplier will not answer all five, you cannot compare their price to anyone else’s.
Frequently asked questions
Is rock wool more expensive than glass wool?
Per cubic metre at the same density, rock wool usually costs more because the fibre is denser and melts at a higher temperature. Per square metre of installed insulation, the gap narrows — or reverses — once you account for the density and thickness your specification actually requires.
Does higher density mean better insulation?
No. Density mainly controls strength, fire performance and acoustic mass. Insulation value comes from thickness and λ. Choose the lowest density that meets your structural and fire requirements.
What is R-value for 100 mm rock wool?
At a typical λ of 0.040 W/(m·K), 100 mm gives R = 2.5 m²·K/W. A denser product with the same λ gives the same R-value — density is not the variable you are buying here.
How do I get an actual price?
Send three things: product and density, thickness, and quantity with destination port. We quote factory-direct from Shandong, China, and reply within one working day.
About this guide
Who maintains it
This guide is maintained by the Taishi Rock Wool export team in Shandong, China — factory-direct rock wool and glass wool from seven production bases with a combined capacity of 800,000 tonnes a year. Technical questions go straight to the factory rather than to a trading desk: WhatsApp +86 175 6050 1246 or email cliu32626@gmail.com.
Standards and sources referenced
- GB/T 25975-2018 — Chinese national standard for rock wool and its products; our production and test reports follow it.
- EN 13162 — European product standard for mineral wool, including how thermal conductivity (λ) is declared.
- EN 13501-1 — fire classification of construction products; class A1 means non-combustible.
- ISO 8301 / ASTM C518 — steady-state thermal conductivity test methods behind any quoted λ figure.
- ASHRAE Handbook—Fundamentals — definitions of thermal conductivity and R-value used here.
- EURIMA — European Mineral Wool Manufacturers Association, technical guidance on mineral wool performance.
- Insulation Institute (NAIMA) — industry technical resources on insulation performance and specification.
Last updated: September 23, 2026