Cropped and Close up image of outdoor dining room installed with Hydronic heating

In-slab hydronic underfloor heating is a highly efficient, straightforward option when of warming your home.  In-slab heating is very popular in modern homes as an alternative to older, more costly, and less efficient heating systems.  In-slab heating can be provided for polished concrete floors and other modern types of flooring.


Hydronic in-slab heating is suitable for large areas (80 m2 +) where the slab is used as heat storage [Thermal mass]. In-slab heating has a slow response time and can take between 1-2 days to heat up, depending on slab thickness and insulation.


REHAU PEX pipe is specifically used for under floor heating. It is a cross-linked polyethylene pipe with an oxygen barrier to prevent corrosion.


With in-slab hydronic heating, we aim for a heat output of 100-120 W/m². A combination of flow and temperature is balanced to suit the heat load requirement of each room.


The hydronic floor heating pipe is installed before the slab is poured. The pipe is attached to either the mesh or the reinforcing rods with 200mm centres (one direction only). With slabs poured directly onto the earth, it is advised to insulate under the slab to avoid heat loss into the ground. All pipe work connects back to a central manifold and onto the nominated heat source.


The hydronic floor heating pipe can be installed across expansion joints with the correct installation method. The minimum concrete coverage over the pipe is 30mm – this means a distance of 50mm from the top of the top mesh to the finished surface of the slab.  Less will mean different more costly installation options.  The minimum coverage is to ensure the structural integrity of the finished slab. Comfort Heat must be informed of any expansion joints in the slab.

Explore Your Choices for In Slab Hydronic Heating

To find out more about in slab hydronic heating, download our brochures below. You can also call or contact us online to speak directly to our experts about your in slab heating options. We’ll be happy to provide all the technical support, guidance and practical help you need.

Please note: In-slab hydronic heating installation requires a range of site-specific metrics. To provide you with technical advice and an accurate quote, we will need floor measurements, specifications and information regarding slab construction.


Pipe Type : Cross linked polyethylene pipe with oxygen barrier
Pipe Diameter : 16mm
Slab Thickness : Minimum 30mm coverage above the pipe
Warranty : 25 years




E-brochure_Polished Concrete