The right diameter depends mainly on your stove’s rated heat output. As a rule of thumb, the internal diameter of your chimney should be at least equal to the diameter of the stove outlet. So, if your stove has a 150 mm outlet, a 150 mm chimney will generally be suitable. For stoves up to 5 kW, 130 mm is usually sufficient, while 150 mm is recommended for 8–12 kW.

Our OSKAR stainless steel chimneys are available in 130 mm and 150 mm, allowing you to connect the most common wood-burning stoves up to approx. 10–12 kW.

Please note: These guidelines do not replace a binding calculation. The exact diameter required is calculated individually in accordance with DIN EN 13384-1, based on the stove output, chimney height and other factors. Before buying, it is therefore best to speak briefly with your local chimney sweep to ensure you order the right system.

How often an OSKAR chimney needs cleaning mainly depends on how you use it, rather than on the material itself:

Typical case (wood-burning stove as supplementary heating):

If the stove is only used occasionally — no more than around 8 days per month for a maximum of 5 hours, or fewer than 30 days per year in total — the German Sweeping and Inspection Regulations (KÜO) require sweeping and inspection once a year.

If the stove is used regularly throughout the year (e.g. as the home's only heat source), sweeping is required up to 4 times a year.

As OSKAR chimneys feature twin-wall insulation, the flue gases stay warm for longer and the draught is more stable. In practice, this results in fewer deposits than with single-wall or masonry systems, but it does not remove the statutory minimum sweeping requirement.

Important: Your district chimney sweep determines the specific sweeping frequency in the fireplace notice based on your actual usage — you cannot determine it yourself.

With proper care and regular maintenance by a chimney sweep, our high-quality OSKAR stainless steel chimney will last well over 30 years. Our OSKAR Care+ guarantee also gives you a 30-year guarantee on your chimney

Basic rule: The chimney outlet must extend at least 40 cm above the roof ridge — or above an imaginary ridge point if the roof is flat or has a pitch of less than 20°.

If the chimney outlet is further away from the ridge (outside a 15° zone around the ridge), it must instead terminate at least 1 metre above the roof surface.

The "radius rule" also applies: The outlet must extend at least 1 metre above all windows, doors and ventilation openings within a radius of 15 metres. Depending on neighbouring buildings, this may increase the required height further.

Special cases:

• For soft roofing (thatch, straw) and solid fuels (wood/coal): 80 cm above the roof ridge instead of 40 cm.
• Different values may apply to flat roofs with parapets; check the applicable state building regulations.

Our OSKAR stainless steel chimneys require a minimum distance of 50 mm from combustible materials. Thanks to the high-quality insulation in our twin-wall systems, this small clearance is sufficient to protect walls, beams and other combustible components safely from radiant heat. Please note that your installation must always receive final approval from the responsible chimney sweep.

A twin-wall stainless steel chimney offers several advantages over a single-wall system. The insulation layer between the inner and outer pipes keeps the flue gases warm for longer, improving the chimney draught and reducing the risk of condensation and tar deposits inside. At the same time, the outer wall stays considerably cooler, which is particularly important when installing near combustible materials. A twin-wall system is usually the better choice for modern, low-emission appliances with lower flue gas temperatures. It is also generally mandatory for freestanding or externally installed chimneys that are permanently exposed to the weather.

You can get a stainless steel chimney from OSKAR starting at 399 euros. Use our configurator to put together the right chimney for you.

If your chimney does not fit, you can return the incorrect parts at any time and simply order the right ones from us online. Not sure whether anything is missing or exactly what you need? No problem – just contact us and we will be happy to help quickly and without any hassle.

The standard warranty is 15 years – our OSKAR Care+ extended warranty lets you easily increase it to 30 years.

Yes, we are a German company based in Hamburg. All chimneys are dispatched from our own warehouse in Hamburg.

The connection technology of the Secure Adjust System (SAS-TEC) is as simple as it is ingenious:

When the components are fitted together, a slight anticlockwise turn locks them securely in place. Locking bands provide additional security and maximum stability.

As all components are enclosed, the insulation remains hidden from view, reliably preventing soot particles from escaping. This gives the SAS-TEC system particularly high stability once the chimney has been fully assembled.

Our twin-wall OSKAR stainless steel chimneys are TÜV-tested, CE-certified and built to last. Made from high-quality V4A and V2A stainless steel, they offer exceptional durability and heat resistance up to 600 °C.

Every OSKAR stainless steel chimney is twin-wall, with 25 mm insulation, and is exceptionally easy to install thanks to our SAS-TEC system – for maximum safety, excellent thermal insulation and an installation process you can truly enjoy.

At an internal temperature of up to 250 °C, the outside of your stainless steel chimney will also become warm. It is hottest around the height of the connecting piece, which is usually out of children’s reach anyway. Although it will not burn you, it is still better to be safe than sorry – this area gets very hot!