This article aims to help you understand

  • What controls a hydronic slab heating system
  • What a boiler does within a floor heating system
  • The two methods of slab heating
  • Demonstration of heat transfer
  • Demonstration of efficiency

A centrally located thermostat of which there is a range of choices is the brains behind a hydronic heating system. When a thermostat control detects that the room temperature has become lower than the target temperature set by programming your control unit – it will call for heat from the boiler to be pumped through the system until the target temperature is met.

The Role of a Hydronic Heating Boiler

In this case, the hydronic heating gas boiler is going to turn on much like an instantaneous hot water system. By burning gas, it transfers heat energy into the water.

With slab heating, the boiler is set to raise the water temperature to 50C. The boiler has an internal pump that circulates the hot water through the flow and return pipes to a manifold.

Slab Heating Pipework

The flow and return pipes run from and to the boiler, to a manifold.

The manifold is made up of a number of blocks, with each block creating a circuit of 100m of pipe covering an area of 20sqm. Therefore if you have an area of 100 sqm to heat then you would require 5 circuits your manifold would have 5 blocks.

The Two Methods of Installing Hydronic Heating

In Slab

In-slab heating is when the pipework is installed within the structural slab of the building. We tie the pipe to a ‘sacrificial’ mesh in a spiral fashion. By spiraling it correctly the floor will be evenly heated and not have cold spots. The structural mesh is then placed on top of our pipework and the concrete is poured as per normal. The system is filled with water and pressurised so that it doesn’t collapse and so that if in the unlikely event it is punctured it is visible. On the rare occasion that slab pipes are punctured, we will conduct an emergency repair and re-pressurise the system to ensure it’s integrity.

In Screed

In-screed heating is where the pipework is installed into a screed or topping slab on top of the structural slab. The benefit of screed heating is that it is insulated underneath and that it is heating a much thinner slab. This makes it more efficient and responsive.

Radiant Heat Transfer

Slab Heating Diagram

The heat energy from the water is transferred into the concrete, and then the concrete radiates heat into the room. This is why it’s so comfortable. There is no blown air which moves dust around. It’s also why it’s so efficient due to the concrete and water slowly releasing the heat energy while the source of the heat – the gas – is no longer being burnt.

Feel free to visit our showroom/selection centre


18 De Havilland Rd, Mordialloc 3195 VIC


252-256 Sydney Rd, Balgowlah 2093 NSW

If you have any questions please write them in the comments section so that we can help you and others with similar questions into the future.