Iso Block System

With regulations governing energy consumption in buildings becoming more and more stringent, the passive house approach is now a realistic option for specification by builders and architects. 

However, when installing a chimney system into a passive house, we are faced with two conflicting requirements — the passage of a chimney through a ceiling or roof has to be sealed and insulated to meet the energy standards and to maintain fire protection, but the chimney system itself has to be adequately cooled for safety reasons. 

The solution to this dilemma is the Metaloterm Iso-block system.

Iso-block provides a lightweight insulated and air tight passage for a stainless steel chimney system through a wall, floor or roof whilst maintaining full fire protection and ventilation for the surface of the chimney.

Saving energy with Iso-block

It is not just passive standard housing that can benefit from Iso-block technology. Because the unique construction retains heat extremely efficiently it can contribute significantly to energy savings in any property.



The illustration on the above shows a typical application where Iso-block has been used in conjunction with the Metaloterm AT chimney system and a wood burning stove. The blocks are fixed at both ceiling and roof level and the intervening length of chimney is enclosed in fire resistant boarding.


By adding high level and low level vents to the enclosure, the heat radiated by the outer skin of the chimney is utilised in the room above the stove.


The AT system is a twin wall insulated chimney ideal for use with wood burning stoves. It has a maximum temperature rating of 600ºC and has the added benefit of the Metaloterm 30 year warranty.

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Metaloterm – Iso Block System