Hydronic Underfloor Heating
What is Hydronic Underfloor Heating?
How does hydronic underfloor heating work?
Benefits of hydronic underfloor heating
- No need for radiators or air conditioning units taking up space within a room.
- Much less maintenance required compared to other heating systems.
- Very economical to run compared to other heating systems.
- Can use solar energy to minimise running costs even further.
- The water can be cooled to provide an all in one heating and cooling system
- Draft and noise free heating.
- Even distribution of heat throughout the room.
- Modern systems can be controlled by a 7-day timer thermostat which allows you to heat specific rooms or spaces independently, using different settings for weekdays and weekends.
- Health benefits due to no recirculation of stale air used by other systems.
Installation and Maintenance
- how the water will be heated – natural gas, LPG, heat pump, solar
- where the boiler will be located – often needs a large area such as a garage or storage room
- type of under floor heating – will it be installed within the slab, in the screed above the slab, or directly under the floor covering
- thermostat – how much control will you require over the heating – time of day, days of week, different rooms
- speed of heating – will you require the floor to heat up quickly or happy for it to be a more gradual heating throughout the day.
Types of hydronic underfloor heating
Hydronic slab heating
The heat from the water warms up the slab first and then radiates into the room above. It can take anything between 24 to 48 hours to realise any benefit depending on the thickness of the cover which acts as form of storage.
The ‘PEX’ Pipe used under the slab which transfers the heated water has been especially designed to prevent corrosion, and is secured prior to the pouring of the slab, to either the mesh or the reinforcing steel rods. To avoid loss of heat into the earth, insulation can be first installed before any of this work begins.
Hydronic screed heating
In-screed installations have a faster response time than in concrete slab installations, as it is closer to the floor surface. The same ‘PEX’ pipe is used but the method of securing it is by either pins attached to insulation foam or clipped to wire mesh. In addition the screed should be reinforced.
Hydronic heating directly under floor surface
The same ‘PEX” pipe is installed and allowances for insulation, pipe diameter and space taken into consideration. The pipe is secured by pins to insulation foam and where necessary notched batons which allow the pipe movement across the floor. The heating pipe is normally installed, before the floors are laid.
Cool your home with the same system
The water that is used to heat your underfloor slab in winter can also be cooled to cool your room in summer. With the addition of a chiller, the cooled water is pumped through the same underfloor slab as used for your heating system, avoiding the need for two expensive systems to heat and cool your home. Find out more …
Underfloor Products

Australian Hydronic Heating and Cooling, a division of AJ’s Plumbing Pty Ltd, work with a range of suppliers and only use the best products on the market. One of our suppliers, Hunt Heating, have a range of top quality underfloor heating products.
A manifold is central to your underfloor heating system, and and is used to distribute the water through. It provides a central place to connect both your supply and return lines. Supply water from the heat source enters the manifold and circulates hot water throughout the system. This Hunt Heating manifold is developed and designed with control valves for every circuit, lower installation depth and the ultimate in versatility.
When laying slab underfloor heating using a pipe positioning board helps create a thermal break between the slab and the screed which means you are only heating up the secondary layer of screed. This increases efficiency as it reduces the time it takes to heat up. The Hunt Heating pipe positioning board is a market leading pre-formed panel with an R 1.0 value.


The most essential element to any underfloor heating system is the pipes, as a faulty pipe can lead to leaks or corrosion. Most underfloor systems now use a PEX (cross-linked polyethylene) pipe as they are flexible, won’t corrode, don’t burst in freezing conditions and are easier to install. This Pex-A pipe supplied by Hunt Heating is the most flexible PEX on the market allowing for the tightest bend radius and less likelihood of kinking.
Thinking of renovating and want to install underfloor heating? The Uponor Minitec underfloor heating system is ideal for renovation projects. It can easily be laid on existing screed, timber or tiles, has a total build height of only 15mm and has a fast reaction time so the floor surfaces can start to feel warm within minutes. The Minitec system can be easily customised to fit around obstacles and the desired floor finish can simply be lay on top, leading to a fast installation.

For more information on underfloor heating download this guide from Hunt Heating – Hydronic Underfloor Heating Guide