Underfloor Heating – In-slab Radiant in-floor heating.


ecoMASTER Underfloor Heating and Hot Water Heating heat pumps provide reliable and cost-effective heating of hot water for both underfloor heating and domestic hot water cylinders.

This is commonly known as heat pump, hydronic (underfloor) heating.

These highly efficient systems are ideal for in-slab or underfloor situations and should be considered when building. In some situations, the same size heat pump can also provide your hot water needs when coupled to a hot water cylinder. As underfloor systems run at lower temperatures than other forms of home heating this improves efficiency and reduces running costs.

The system comprises of a heat pump that is generally located outside the dwelling, which couples to an indoor manifold or to the optional hot water cylinder. From the manifold hot water is distributed around the slab by a network of very durable plastic pipes. Location of heat pumps and manifolds needs some consideration at the design stage to enable easy installation, access and service. A circulation pump either on or near the heat pump moves hot water to where it is needed.

For even and reliable heating, it is recommended that water tube spacing is at 150mm centres and limited to circuits of no more than 120 metres. While longer runs and wider spacing is possible this may impact on over quality and distribution of heat throughout the slab or foundation.


The water tubes are generally fixed by staples in circuits on top of the polystyrene insulation. These are a dual layer polyethylene pipe with cross link, heat, aging and oxidation inhibiting properties.

The reinforcing mesh is laid over the top and then about 100mm of concrete is poured over the top. This mass of concrete holds heat almost as a gentle giant storage unit and releases heat over a period of time.

How does underfloor heating work?

Where a single heat pump is used for in-slab underfloor heating and domestic hot water heating (dual system) the in-slab water circuit is routed through a coil in a purposely built hot water cylinder. This means the domestic hot water is never mixed with the in-slab underfloor heating water.

Because heat pumps are extremely efficient this means your whole house can be evenly heated using in-slab, under floor hydronic heating very cost effectively compared to other forms of heating.

It is important to note that any heating only replaces any heat lost from a building and the best results come from houses that are well insulated, have solar gain and energy efficient products. We recommend under slab and perimeter insulation.

How does underfloor heating work