If you’re building a new home, budgets are always a consideration. A hydronic heating system always has to be custom-designed to suit your house plans. However, there are a few rules of thumb to estimate what a complete installation is likely to cost.
Note that these prices are based on hydronic heating in Sydney, but are indicative of most Australian urban centres.
There are two components to a hydronic underfloor heating system – the boiler (or heat pump) and the in-slab pipework.
What type of boiler?
In most Australian cities, gas boilers are most common as they’re by far the cheapest to install and have modest running costs.
Generally a gas boiler will cost around $4000-$5000 installed and will provide enough heating for most houses up to around 300m2. Most often this is connected to the natural gas network, but if your property isn’t on the network then you’ll need LPG bottles. This increases your running costs quite a bit, but can still be an attractive option for a small property.
If you don’t have gas available or you’d prefer to steer away from fossil fuels, then another popular option for you hydronic heating is an air-to-water heat pump.
A heat pump resembles an air conditioner’s outdoor unit, but instead of heating or chilling the air, it pumps out hot or cold water. The running costs are slightly cheaper than a gas boiler, but it has the advantage that because it runs off electricity it can be powered by a solar system.
Depending on how many solar panels you install, you could just about run your heat pump for free. However, you’d be looking at between $5k – $12k depending on how many panels you need.
A typical air-to-water heat pump will cost around $8k – $12k, and will suit up to 120m2. For larger homes you’ll need to allow for a bigger heat pump. If you’re heating a space much larger than 180m2 then you’ll also need 3-phase power.
Other types of boilers are also available. Diesel boilers are a popular choice for rural areas, as they’re cheaper to install than a heat pump for the heat output they provide. Expect around $10k installed, suitable to heat a home up to 300m2. They also burn very clean and don’t produce any smoke. However, you’ll need to have a diesel fuel tank on site which doesn’t suit everyone.
Once you’ve selected your boiler, you’ll have to allow for the in-slab pipework and associated components. The cost of this depends on the area of floor to be covered.
As a guide, this typically works out to around $75 per square metre installed. As you’d expect, this will likely come down a bit for larger homes, say 300m2 or above. Smaller areas (less than 100m2) will probably cost a bit more.
Here are some expected costs for typical hydronic underfloor heating systems:
| Heat source | Heated floor area | Typical installation cost |
| Gas boiler | 50m2 | $12,000 |
| Gas boiler | 200m2 | $20,000 |
| Heat pump | 50m2 | $17,000 |
| Heat pump | 200m2 | $30,000 |
| Diesel boiler | 200m2 | $25,000 |