Heat loads
Room-by-room sizing
Size each zone based on calculated heat loss, including glazing, insulation, orientation and outdoor design conditions.
Hydronic heating
Hydronic Heating Systems
Explore water-based heating for your home, from underfloor heating to radiators. SmartHeat plans the heating system and heat source together, with design, supply and installation across Sydney and NSW.
Water-based heating systems
Underfloor, radiators and towel rails
Heat pump and boiler compatibility
Design, supply and installation across NSW
Hydronic heating overview
What is hydronic heating?
Hydronic heating uses warm water to carry heat around a building. A heat pump or boiler heats the water, which circulates through pipes to underfloor heating, radiators or towel rails. After releasing heat, the water returns to the heat source to be reheated.
Planning a system involves three connected choices: how to heat the water, how to release heat into each room, and how to control different areas. Your project stage and floor construction help determine the options to explore.
The basics
How does hydronic heating work?
A heat source warms the system water. A circulation pump moves it through the pipework to floor circuits or radiators, which release heat into the rooms. The cooler water then returns to the heat source and the cycle repeats.
Thermostats and zone controls help manage where heat is needed. The heat source, pipework, heating surfaces and controls need to work together as one system.
Your heating options
Underfloor heating, radiators and heat sources
Underfloor heating places the heating surface beneath the floor. In-slab pipework is planned before a new concrete slab is poured; in-screed pipework sits above the structural slab within a screed layer. Floor levels, insulation and the finished flooring need to be considered together.
Radiators provide room-based heat from wall-mounted panels. They can be considered where floor heating is not practical, subject to pipe access, available wall space and the heating output required.
A heat pump or boiler supplies the warm water. Choose the heat source alongside the room heating requirements, operating water temperature, available energy supply and equipment space.
Before you choose
Benefits and practical considerations
Hydronic underfloor heating and radiators deliver room heat without relying on ducted airflow. Zones can be designed around how different areas of your home are used, and a coordinated system can combine different heating methods.
Installation needs to fit the building. Underfloor heating must be coordinated with floor construction and finishes; radiators require wall space and pipe access. Both need space for the heat source and associated equipment.
Warm-up time depends on the floor or radiator type, starting temperature, insulation and system design. Discuss whether you want steady background warmth or heating focused on particular rooms and times.
Planning your budget
What affects the cost of hydronic heating?
A useful quote needs to describe your project, not just the floor area. These factors help define the scope:
- Rooms and heating requirements: the areas to be heated and the number of control zones.
- Heating method: underfloor circuits, radiators, towel rails or a combination.
- Heat source: the equipment and its connection to the heating system.
- Building work: floor preparation, pipe access, equipment location and coordination with other trades.
- Delivery scope: design, supply, installation, controls and commissioning.
Making a comparison
What should a heating quote include?
Check whether each quote includes the heat source, pipework, radiators or floor circuits, controls, installation and commissioning. Clarify GST, electrical work, floor preparation and making good, and identify work to be completed by other trades.
Running costs are a separate consideration. They depend on building heat demand, insulation, heating schedule, zoning, heat source, operating water temperature and energy tariffs. A meaningful estimate needs these assumptions to be stated.
Hydronic systems
Compare hydronic systems by floor construction and project stage.
Start with the system type, then move into the detail page that best matches the project stage and construction method.
01
Hydronic Underfloor Heating
Concealed radiant floor heating for new builds, renovations and projects where comfort should come through the floor.
02
Hydronic Underfloor Heating In-Slab
Pipework embedded into a new concrete slab for steady background radiant heating and strong thermal mass.
03
Hydronic Underfloor Heating In-Screed
Pipework installed above the structural slab within a screed layer for a more responsive radiant floor system.
Choose by project stage
Which hydronic heating option suits your home?
| Your project | Options to explore | What to check first |
|---|---|---|
| New home with a concrete slab | In-slab hydronic underfloor heating. | Coordinate the heating layout, insulation and construction programme before the slab is poured. |
| Renovation with a new floor build-up | In-screed hydronic underfloor heating. | Review available floor depth, finished levels and the proposed floor material. |
| Existing home with floors remaining | Hydronic radiators, subject to a review of the building. | Check pipe routes, wall space, room heating requirements and equipment location. |
Design considerations
Hydronic heating is a complete system, not a single product.
Heat emitters, heat source, pipework, controls and water temperatures must be engineered as one system.
Heat source
Temperature and capacity matching
Match heat pumps or boilers to the building load, flow temperature and required emitter output.
Hydraulics
Flow and pipe sizing
Coordinate pipe sizes, circuit lengths, manifolds and pumps to maintain design flow rates.
Controls
Zoning and temperature control
Coordinate thermostats, actuators, valves and weather compensation for stable, efficient zoning.
Construction
Build-up and sequencing
Plan pipe layouts, floor build-ups and trade sequencing before in-slab, in-screed or radiator installation.
Commissioning
Testing and balancing
Pressure test, flush and balance the system, then verify controls, zones and heat-source operation.
Related system decisions
Plan the supporting parts of the system.
These related elements help shape the final system specification and are useful next steps during design.
FAQ
Common questions.
Is hydronic heating expensive to run?
Running costs depend on building heat demand, insulation, heating schedule, zoning, heat source, operating water temperature and energy tariffs. Compare estimates using the same assumptions about the home and how it will be heated.
Can hydronic heating be installed in an existing home?
It depends on the building and available construction depth. When installing hydronic heating in an existing home, floor build-up, pipe routes, wall space and plant location should be reviewed first. Radiators, towel rails and some in-screed systems may suit renovations, while in-slab heating is generally planned for new concrete slabs.
Can hydronic heating be zoned?
Yes. Thermostats, manifolds, valves and controls can help different rooms or areas operate separately, so lightly used spaces do not need to be heated the same way as primary living areas.
Should I choose a heat pump or boiler?
That depends on the heat load, required water temperature, emitter sizing, available power, plant space and project goals. Air-to-water heat pumps can be a strong all-electric source when the full hydronic system is designed around them.
How quickly does hydronic heating warm up?
Response time depends on the emitter and floor construction. In-slab systems provide steadier background heat through thermal mass, while in-screed systems, radiators and towel rails can respond more quickly when sized and controlled correctly.
Is hydronic heating the same as electric underfloor heating?
No. Hydronic underfloor heating circulates warm water through pipes. Electric underfloor heating uses heating cables or mats. Room size, floor construction and project stage help determine which approach to consider.
Which floor finishes can I use?
The proposed floor finish needs to be checked against the heating design and the flooring manufacturer’s requirements. Share the product details before the floor build-up is finalised.
What should I send with my enquiry?
Include the project suburb, whether it is a new build or renovation, the rooms to be heated, the project stage and any available drawings or floor construction details. If some details are undecided, tell us what is currently known.
Guides
Plan with practical guidance.
Product Selection
Electric vs Hydronic Underfloor Heating
Compare electric and hydronic underfloor heating to find the right option for your room size, floor construction and project stage.
Product Selection
Hydronic Heat Pump vs Gas Boiler
Compare hydronic heat pumps and gas boilers, including how each produces heat, water-temperature requirements and suitability for new or existing systems.
Fundamentals
How Does a Hydronic Heating System Work?
Learn how a hydronic heating system heats water, distributes it to radiators or underfloor circuits, and returns it to the heat source in a continuous loop.
Projects
Projects using hydronic heating systems
Hydronic in-screed underfloor heating installed over 10mm Profi Duo boards across a South Bowenfels residence.
South Bowenfels, Central Tablelands, NSW
10mm Profi Duo Board Hydronic Underfloor Heating – South Bowenfels
Hydronic Underfloor Heating - In-Screed
A multi-zone hydronic underfloor heating system installed at a Bar Beach residence.
Bar Beach, Newcastle, NSW
Hydronic Heating System – Bar Beach
Hydronic Underfloor Heating - In-Screed
Hydronic in-screed underfloor heating using 10mm pipe installed across multiple zones of a Bronte residence.
Bronte, Eastern Suburbs, NSW
Hydronic In-Screed Underfloor Heating – Bronte
Hydronic Underfloor Heating - In-Screed
Start with the system
Plan your hydronic heating with SmartHeat.
Tell us the project suburb, whether you are building or renovating, the rooms you want to heat and your project stage. Include available floor plans, floor construction details and information about any existing heating.
Need full delivery support?
Review SmartHeat's design, supply and installation service for complete project coordination.
Design, Supply & Installation