Hydronic Underfloor Heating
What is Hydronic Underfloor Heating?
How does hydronic underfloor heating work?
The boiler used for heating the water can be powered using one of several energy efficient and environmentally means. The most common is via natural gas or LPG, or you can also use an electric heat pump to heat the water. Perhaps the most efficient way of powering the boiler is by using solar energy but you may have to install a gas or heat pump backup for days that are cloudy.
Heat Sources and Running Costs
There are a number of energy sources and systems you can use to heat your water for your underfloor heating, including natural gas or LPG boilers, electric air to water heat pumps, wood pellet boilers, a diesel boiler or electric boiler.
Running costs are a key consideration and one which can be challenging to answer due to the variability in types of fuels and prices. Actual cost of heating will depend on the area heated, running time, thermostat settings, house insulation, energy tariffs and the local climate. The costing graph below is based on the following typical heat load.
Heat Source Outputs & Cost Per Unit
Running Cost Calculation Example - Wood Pellet
22.3 kw maximum power = 4.9 kg/h
1 kg of wood pellets = $0.52
Figures are accurate as of 1st August 2017 and should be used as example only. Excludes – supply, rental and delivery charges, on time payment, member discounts, government subsidies (eg agricultural diesel), and GST.
Australian Hydronic Heating and Cooling can work with you to determine the best heat source for your underfloor system.
For more information on heat sources and running costs please refer to the Hunt Heating Underfloor Heating Guide.
Benefits of hydronic underfloor heating
Installation and Maintenance
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 …
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.