Twin Wall to Twin Wall Increaser Ø 125 - Ø 150
At a Glance
- - Increases flue diameter from Ø125 to Ø150 for a secure, efficient fit
- - Constructed with durable 304 and 316 stainless steel for long-lasting performance
- - Incorporates compressed rockwool insulation (200kg/m³) for optimal thermal efficiency
- - Quick and reliable installation using a security Locking Band
- - Fully HETAS approved and CE marked to meet stringent safety standards
- - Versatile compatibility with solid fuel, gas, and oil appliances

Please Note: All dimensions refer to the internal diameter of flues. If unsure, please call 01670 206999 to ensure you choose the correct products.
We Won't Be Beaten On Price
At National Flues, we continuously monitor competitor prices. This ensures that we consistently offer you the best deals on all our products. Here’s how we keep your costs low:
- Daily Price Matching: Our team adjusts prices to ensure we stay competitive.
- Bulk Purchasing Power: We sell a lot, so we can negotiate better rates with suppliers, passing the savings directly to you.
- Operational Efficiency: We have streamlined processes to reduce overhead.
Price Match Guarantee: If you find the same product cheaper within 48 hours, we’ll match it and refund the difference.
Free Delivery Over £100: Orders over £100 are free delivery (call us if delivery is required outside the mainland UK).
“I saved 20% on my purchase compared to other retailers. Exceptional service!” – Jane D.
Have Questions?
Phone: 01670 206999
Email: [email protected]
- Info
- Specs
- Install
- FAQs
The Twin Wall to Twin Wall Increaser Ø 125 - Ø 150 is a critical component for any chimney system where an increase in flue size is required. Specifically designed for use with solid fuel, gas, and oil appliances, such as woodstoves, gas coal effect fires, and boilers, this increaser caters to a wide range of heating setups. Constructed with a robust 304 grade stainless steel outer skin and a 316 grade stainless steel inner skin, both featuring a thickness of 0.4mm, this product is engineered for durability and longevity.
The incorporation of compressed rockwool insulation, with a density of 200kg/m3, ensures optimal thermal efficiency and safety. All components are fully welded, enhancing the structural integrity. For installation, the Twin Wall Insulated Chimney parts are secured with a reliable Locking Band, and it is crucial to maintain a 50mm distance from any combustible materials to ensure safety.
The TWPro Twin Wall system is HETAS approved and CE marked, adhering to stringent safety standards and regulations.
SKU: 2-125-004
Technical Specifications | |
---|---|
Model | Twin Wall to Twin Wall Increaser u00d8 125 - u00d8 150 |
Diameter Range | u00d8125 to u00d8150 |
Inner Material | 316L Stainless Steel (0.40mm thick) |
Outer Material | 304 Stainless Steel (0.40mm thick) |
Insulation | Compressed Rockwool (200kg/mu00b3) |
Fuel Compatibility | Wood, Oil, Gas, Low sulphur coal |
Approvals | HETAS / CE |
Minimum Clearance | 50mm from combustible materials |
Designation | EN1856-1 T600 N1 W V2 L50040 G50; EN1856-1 T200 P1 W V2 L50040 020 |
System | TWPro Twin Wall |
Delivery Information +
We work relentlessly to ensure you get your order fast. Estimated delivery for this product is Tuesday, April 8th. If you need faster stove or fireplace delivery please give us a call. We can often reduce longer lead times if we pay the carrier £25 for express delivery. Visit our Shipping Information page for more information.
Warranty & Returns +
All our products come with warranties. Mi-Flex offers a lifetime guarantee. Returns for damaged items are covered by insurance; non-damaged returns incur return delivery costs.
Price Match Guarantee +
We will match any price like for like. If you find it cheaper within 48 hours, we'll refund the difference.
Compatible and other products that may be of interest...
National Flues Ltd Verdict
Our Twin Wall to Twin Wall Increaser Ø 125 - Ø 150 is a must-have for any chimney setup requiring increased flue diameter. Made from high-quality stainless steel, this increaser ensures top-notch performance and is suitable for a variety of fuel types including solid fuel, gas, and oil. With our reliability in pricing and delivery, National Flues is your go-to supplier. We proudly serve both retail and trade customers nationwide.
The Twin Wall to Twin Wall Increaser Ø 125 - Ø 150 is used to increase the diameter of a twin wall flue pipe system, providing a safe and effective transition for various heating appliances.
National Flues is a leading supplier of high-quality fireplaces and flues, catering to both retail and trade customers across the UK. Known for unbeatable prices and reliable delivery, we pride ourselves on excellent customer service and industry expertise.
