Comfort
Even warmth from the building fabric
Pipework embedded in the concrete slab turns the floor into a large low-temperature radiant surface, reducing cold spots and harsh bursts of hot air.
Hydronic underfloor heating
In-Slab Hydronic Heating
In-slab hydronic heating for Sydney and NSW projects, designed into the slab before concrete is poured.
Installed before the slab pour
Designed around the construction programme
Compatible with efficient heat sources
Quiet radiant comfort across the floor
How it works
Warm water pipework becomes part of the slab.
Hydronic in-slab heating circulates warm water through pipework installed within the concrete slab. The water is heated by a central energy heat source, then distributed through designed loops beneath the finished floor.
Because the slab stores and releases heat, the system creates a steady ambient temperature across the room. It is quiet, concealed and suited to projects where comfort, efficiency and clean interior detailing are part of the brief.
Benefits
A durable heating layer planned into the build.
The best results come from early coordination between the heating design, slab design, insulation and construction sequence.
Efficiency
Cost-effective with no floor build-up
Pipework sits within the structural slab below the reinforcement, avoiding additional floor height and architectural impact while providing a cost-effective heating solution.
Build stage
Planned before concrete is poured
The layout is coordinated while the slab is formed and reinforcement is ready, so zones, manifolds and pipe routes are resolved before concrete works begin.
Operation
Silent heating with no visible emitters
Once installed, the heating is concealed within the slab and controlled by thermostats or a wider control strategy for each zone.
Air quality
Less air movement through occupied rooms
Radiant floor heating warms the room without relying on strong fan-driven air movement, helping maintain a calmer indoor environment.
Projects
Well suited to new builds and major works
Hydronic in-slab heating is well suited to projects where ceiling height and floor build-up need to be minimised.
Design and installation
Resolved before the concrete pour.
In-slab heating is most effective when the heating layout is part of the construction plan, not an afterthought once site work has already started.
- 01
Review the plans
We assess slab construction, room layout, floor finishes, heat loads and available plant locations.
- 02
Design the zones
Pipe spacing, loop lengths, manifold positions and control zones are documented before site works begin.
- 03
Coordinate with site
Installation is aligned with formwork, insulation, reinforcement and other services before the concrete pour.
- 04
Test and commission
Pipework is pressure tested, protected through the pour and later connected to the heat source and controls.
Technical planning
What needs to be decided early.
Slab heating affects services coordination, floor build-up, controls and the heat source. Early review helps keep the system practical on site.
- Pipe position
- Pipework is fixed within the slab build-up to suit the structural design, reinforcement layout and heating output required for each zone.
- Insulation
- The slab and edge conditions should be considered early so useful heat is directed into the building instead of being lost to the ground or perimeter.
- Thermal response
- Concrete stores heat well, so in-slab heating is best operated as steady background comfort rather than rapid on-off heating.
- Heat source
- Air-to-water heat pumps, boilers, geothermal systems, solar-assisted designs and biomass options can all be considered depending on the project requirements.
Suitable projects
Where in-slab heating makes sense.
- New concrete slab homes
- Architect-designed residences
- Minimal floor height
- Commercial buildings with early services coordination
- Projects seeking concealed heating with no wall radiators
- Buildings using efficient central plant or heat sources
FAQ
Common in-slab hydronic heating questions.
When is in-slab hydronic heating installed?
Installation takes place during the early slab stage, after slab preparation and reinforcement are ready and before the concrete pour.
Can in-slab heating be added after the slab is poured?
Not as a true in-slab system. Existing slabs usually require another approach, such as in-screed hydronic heating or another heating system suited to the floor build-up.
Is it compatible with heat pumps?
Yes. Hydronic slab heating works at lower water temperatures than many radiator systems, which can make it a strong match for correctly sized air-to-water heat pumps.
How is the system controlled?
Control is usually managed through thermostats and zoning, with manifolds and valves dividing the building into practical heating areas.
Projects
Projects using in-slab hydronic heating
Plan before the pour
Design in-slab heating before site decisions lock in.
Share your drawings and project stage. SmartHeat can review the slab heating requirements and recommend the next step.
Need full delivery support?
Review SmartHeat's design, supply and installation service for complete project coordination.
Design, Supply & Installation