So, no chimney in the room where you would like your stove? Why not create one?

Twin wall flue is also known as DW (double wall) flue.

Twin wall flue pipe cannot be cut to length by you to make it fit, So one needs to plan carefully when installing a twin wall flue chimney. 

If you are installing a wood burning stove, boiler or gas appliance and you are planning to run your flue system either through a wall, a floor or externally you will need to use a twin wall flue system.

Twin wall flue pipe has a 1 inch layer of insulation around the pipe.  Accordingly, the external diameter of twin wall pipe is always two inches larger than the internal diameter, which is the diameter it is quoted in.  This is because the internal diameter is the crucial figure when designing a wood burning stove flue system but you should always be aware of this as, for instance, if you purchase a 5 inch diameter twin wall pipe the external diameter will be 7 inches – a big difference if you were not expecting this!