Hydronic Underfloor Heating System

Underfloor heating is a common method of heating homes throughout Europe and North America. It’s less common in Australia but is quickly becoming much more popular.

There are two types of underfloor heating available – electric and hydronic.

Electric underfloor heating consists of electric wires, usually installed under tiles. The wires heat up and warm the tiles. These types of systems are cost-effective to install, but expensive to run. They’re suitable for bathrooms and other small areas that aren’t in use for long periods of time.

Hydronic underfloor heating systems consist of a network of small pipes, usually embedded in a concrete floor slab. Hot water is run through the pipes, which heats up the concrete slab. Because of the extra materials involved, these systems are more expensive than electric underfloor heating systems to install, but they’re much more cost-effective to operate.

How are hydronic underfloor systems installed?

The most common (and cost-effective) method that’s used in Australia is the pipework is tied to the steel reinforcing mesh before the concrete floor slab is poured.

If your project has a “topping” slab then usually the hydronic pipework will be installed in the topping slab rather than the structural slab. This is to keep the pipes close to the top surface so the heat can radiate into the house. Topping slabs are common with polished concrete floors or if your property has an existing slab, and you’re constructing a new floor slab on top.

Generally, the pipework is installed in a ‘spiral’ pattern, spaced 200mm apart. This ensures even heat distribution throughout your house.

Our engineers will design a suitable pipework layout based on your building plans, and we’ll coordinate with your builder to install the pipes once your steel is in place.

How do you heat the water?

The hydronic heating system isn’t connected to your domestic hot water system (used for your showers, basins etc.) Instead, the hydronic heating system is a separate, sealed circuit with its own heat source.

In Australia, the most common heat source is a gas boiler. These are cost-effective to install and run, and the boilers are compact in size.

Electric heat pumps are starting to become more popular, especially in areas not connected to a gas network. A heat pump is a similar mechanism to an air conditioner, except that it is designed to heat water rather than air.

Heat pump systems are more expensive to install than gas systems, but they can be cheaper to run especially if you’re also installing solar panels, which will produce free electricity to run the heat pump.

Alternatively, there are a range of other fuel types available.

Will the pipes leak?

Once the pipework is embedded in the concrete, it’s very low maintenance. The pipes are continuous lengths of plastic polymer pipe (usually around 100m long), so there are no joints or fittings within the concrete that can fail.

The only way for the pipes to leak is if they’re damaged during building. We pressurize the pipework with compressed air during construction to monitor its integrity, so we know if the pipes have been damaged by watching the pressure gauge.

Once your home is complete, there’s really no way for the pipework to fail. In fact, this is the least likely thing to go wrong with a hydronic heating system. There are many other components more likely to need maintenance, but fortunately these are all accessible for servicing. We recommend that you have your heating system serviced annually, before winter.

How is the system controlled?

We’ll install a thermostat that lets you adjust the temperature in your home. More complex systems might be divided into different zones, and each zone would have its own thermostat.

Hydronic underfloor heating systems work by heating the entire concrete floor slab of your home. Because this is a large mass, it typically takes around 24 hours to heat up from cold. For this reason, we always recommend that you turn on your underfloor heating system at the start of winter, and leave in on until the end of the season.

You can still turn the temperature down using the thermostat, so the boiler only runs when needed. This is the most efficient and cost-effective way to run the heating system.