Hydronic Heating Running Costs in Australia (2026): By City & Heat Source

Every hydronic system, whatever the brand, follows the same arithmetic:

Running cost = heat demand (kWh) ÷ efficiency × energy price

• Heat demand is the heat your home loses over a winter, in kilowatt-hours. It depends on climate, floor area, insulation, glazing, draughts and the temperature you keep.
• Efficiency is the heat delivered per unit of energy bought: a heat pump's seasonal COP (3.5–5.5 in the right conditions), about 0.9 for a condensing gas boiler and exactly 1.0 for an electric boiler.
• Energy price is the usage rate on your bill: cents per kWh for electricity, cents per megajoule (MJ) for natural gas.

Gas needs one conversion: 1 kWh = 3.6 MJ. Gas at 4 c/MJ costs 14.4 c per kWh, and a 90%-efficient boiler turns that into heat at 16 c per kWh. A heat pump at COP 4 on 30 c/kWh electricity delivers heat at 7.5 c per kWh — the whole heat pump vs gas argument in one line, before the gas supply charge is even counted.

The emitters don't appear in the formula. Radiators, underfloor loops and skirting use no energy themselves; they matter only through the water temperature they need, which changes the heat pump's COP.

Tariffs vary by state, network, retailer and plan, and change every year. The figures below are round example numbers chosen to show the method — not quotes or forecasts. Take the usage rates from your own bills, or compare plans on the government's free Energy Made Easy service (Victorians use Victorian Energy Compare), and re-run the sums.

Two caveats. The gas supply charge only disappears if you disconnect from gas entirely. And a heat pump's seasonal COP sits below its headline rating because of cold weather and defrost cycles, so we've used conservative figures for colder cities.

The quickest comparison is the cost of delivering a fixed block of heat. At the example rates above:

The pattern holds at almost any realistic tariff: an air-to-water heat pump delivers heat for roughly half the cost of a gas boiler on grid power and about a quarter of an electric boiler. Across our installs, heat pump running costs are typically 60–75% lower than gas. On a flat grid tariff at our example rates the gap is nearer 50%; it widens into that range once you leave the gas network and run part of the heating on solar or an off-peak rate.

Hardware sets the ceiling. The Maxa i-290 R290 monoblock is rated at a heating COP of 4.94 on its 16 kW model, across a 6–27 kW range, and the Immergas Magis heat pump range starts with a compact 4–6 kW band for apartments and townhouses. The Viessmann Vitodens 100-W condensing boiler is rated up to 98% efficient at its best operating point, but only approaches that figure when the return water is cool. Weighing a switch from gas? Our guide to replacing a gas hydronic boiler with a heat pump covers the retrofit side.

Climate sets heat demand. Scaling our 200 m² example home by heating degree-days (HDD, base 18 °C) — Canberra about 2,300, the upper Blue Mountains about 2,000, Melbourne about 1,500, Sydney about 700 and Brisbane about 150 — gives these illustrative annual space-heating costs. Gas is shown as usage plus the $292 supply charge, which you only save by leaving gas entirely.

Figures are rounded to the nearest $10 and cover space heating only, not hot water or summer cooling. Your own number could easily be half or double these; the method is the point.

• Hydronic heating Canberra: the longest heating season of any capital, so the heat source is worth thousands of dollars over a system's life. For ACT-specific rates and the gas phase-out, see our Canberra hydronic heating running costs guide.
• Hydronic heating Melbourne: roughly double Sydney's load, with a −1 °C design temperature. Swapping an existing gas boiler for a heat pump is where most Melbourne savings lie.
• Hydronic heating Geelong: a heating season close to Melbourne's, so start from the Melbourne row and adjust for your home's insulation and exposure.
• Hydronic heating Albury: inland winters with frostier nights than Melbourne's; expect a figure between the Melbourne and Canberra rows, and specify a frost-rated heat pump.
• Hydronic heating Blue Mountains: a near-Canberra load with −4 to −6 °C design temperatures, so cold-climate heat pump ratings matter more here than almost anywhere in NSW.
• Hydronic heating Sydney: modest demand means the gas supply charge is a large share of a gas system's total, which tilts Sydney firmly toward a heat pump.
• Hydronic heating Newcastle: a coastal load close to Sydney's; use the Sydney row, adjusting upward for inland Hunter sites with colder nights.
• Hydronic heating Brisbane: heating alone barely registers. Hydronic earns its place here as a reversible heat-and-cool system, and summer cooling — not modelled above — is the bigger running cost.

After the heat source, the building and your settings decide the bill. Government guidance puts numbers on the main levers:

• Thermostat. The federal energy.gov.au winter guide recommends heating to 18–20 °C and says every degree you increase your heating can add 5–10% to your energy costs. Radiant warmth often feels comfortable at a slightly lower setting than blown air.
• Insulation and windows. The same guide estimates effective insulation can reduce heating and cooling costs by 45%, and that up to 40% of a home's heating energy can be lost through windows — so heavy curtains and better glazing are running-cost upgrades too.
• Draught-proofing. Sealing gaps around doors, windows and floor junctions can save up to 25% on heating bills.
• Zoning. Heat the living zone in the evening and bedrooms overnight, not the whole house all day. Programmable controls such as Maxa thermostats make the schedule stick.

Before investing $20,000–$60,000+ in a whole-home system, money spent on insulation and sealing can let us specify a smaller heat source and lower every bill after it.

A heat pump's COP climbs as the water it produces gets cooler, so the emitter is a running-cost decision, not just a design one.

• Underfloor heating runs at 35–45 °C flow, the heat pump's most efficient band, so the cost to run underfloor heating on a heat pump is usually the lowest of any hydronic layout. In-slab systems respond over hours and run long, gentle cycles with modest setbacks. The government's Your Home guide notes that in-slab heating suits steady rather than occasional use, that zones and thermostats are essential to reduce energy use, and that slab edges — ideally the whole slab — should be insulated.
• Radiators run at about 45–55 °C and warm a room in 15–25 minutes, suiting households that heat in shorter bursts. Sizing up — a K22 double-panel or K33 triple-panel IMAS radiator where a single-panel K11 would just cope — meets the same heat loss at a lower flow temperature and a better COP. See the full hydronic radiators range.
• Skirting heating sits between the two; our comparison of ThermaSkirt vs radiators vs underfloor heating covers the trade-offs.

The trap is undersized radiators on a heat pump: the system must run hot, the COP sags toward 3 and the bill rises by a third (compare the $75 and $100 rows above). Condensing gas boilers lose out too, because they stop condensing when return water runs hot.

Because a heat pump is all-electric, rooftop solar changes its maths in a way gas never can. Solar you use on site costs only the feed-in tariff you forgo — about 5 c in our example — so heat made at COP 4 from your own panels costs around 1.3 c per kWh.

The catch is timing: solar peaks at midday, heating demand in the morning and evening. Thermal mass bridges the gap — an in-slab underfloor system can charge the slab through the day and coast into the evening. Your Home recommends the same approach: pre-heat a well-sealed, well-insulated house when rooftop solar has excess power or low- or no-cost tariffs are on offer, so you avoid running in the evening peak. Radiators store less heat but can still pre-heat living areas in the afternoon.

On a time-of-use tariff, schedule the heavy lifting into solar-soak, shoulder or off-peak periods and keep peak running to topping up. On a demand tariff, stagger zone start times so the heat pump isn't ramping every zone at once. Our solar hydronic heating guide covers solar thermal collectors, a different route to the same goal.

Moving water and staying ready also uses electricity — small next to the heat source, but it runs for thousands of hours.

• Circulating pumps. Your Home names uninsulated circulation pipes and unmanaged pump use as the main causes of higher hydronic running costs. A variable-speed ECM circulating pump uses up to 80% less electricity than an old fixed-speed unit. As an illustration, a pump drawing 25 W for 1,500 hours uses about 38 kWh (around $11 at 30 c); an old 100 W pump over the same hours uses 150 kWh (about $45), more if it runs year-round.
• Heat pump standby. Outdoor units keep their controls powered, and many use small heaters to protect the compressor or prevent icing in cold weather. Check the standby figure on the datasheet: small, but continuous.
• Gas boilers use electricity for the fan, controls and pump, and the gas supply charge — about $292 a year at our example rate — is effectively the standby cost of staying on gas.
• Pipe insulation through subfloors and roof spaces keeps the heat for the rooms you're paying to warm.

We recommend an annual service of the heat pump or boiler, checks of system pressure, pumps and inhibitor levels, and in older systems a power flush every 5–7 years to clear sludge. Annual servicing also keeps manufacturer warranties valid.

It pays for itself in efficiency. Sludge, trapped air, a blocked strainer, a dirty outdoor coil or a fouled boiler heat exchanger all push a system below its rated efficiency, so the bill drifts up without anything obviously failing. Ask for the annual service price with any quote so you can compare true lifetime cost.

Our hydronic heating cost guide covers the install side, and the heat pump rebates guide explains why not to count on a rebate: STCs apply to registered heat pump and solar water heaters, not to air-to-water heat pumps used for hydronic space heating.

Electric boiler running costs are simple: every kWh of heat costs a full kWh of electricity. Whether that's acceptable depends on how much heat you need.

Where it's fine. A well-insulated 70 m² Sydney apartment needing, say, 1,500 kWh of heat a year costs about $450 on an electric boiler at 30 c/kWh, against about $100 on a heat pump at COP 4.5. A $350-a-year difference may never repay a heat pump's extra cost and complexity — especially where strata rules or a lack of balcony space rule out an outdoor unit. Compact, flueless and silent, electric boilers also suit granny flats and occasional-use zones.

Where it's ruinous. In a 200 m² Canberra home the example bill is about $5,400 a year against roughly $1,540 for a heat pump — close to $3,900 a year, or tens of thousands of dollars over the system's life. Your Home notes that direct electric in-slab heating generally has the highest energy use of any heating system, and an electric boiler feeding slab loops makes heat at the same one-for-one rate. If a cold-climate whole-home quote uses an electric boiler to keep the upfront price down, ask what it will cost to run. Our electric boiler vs heat pump guide and the hydronic boilers range set out the alternatives.

1. Start with a room-by-room heat-loss calculation, so the heat source is sized to your home, not a rule of thumb.
2. Choose a heat pump over a boiler wherever an outdoor unit can go, and a cold-climate-rated model in Canberra, the Blue Mountains, Albury and Melbourne's colder fringes.
3. Run the lowest flow temperature that keeps rooms warm: underfloor, or generously sized radiators.
4. Insulate and draught-proof before or alongside the install, including slab edges and exposed pipe runs.
5. Set 18–20 °C, zone the house and schedule each zone around how you live.
6. Shift heating into solar and off-peak hours, especially with in-slab underfloor.
7. If gas will only be used for heating, plan to disconnect and drop the supply charge.
8. Fit a variable-speed circulating pump and set it to the correct curve.
9. Service annually and keep inhibitor levels correct.
10. Re-check your tariff every year and compare plans when your usage changes.

• energy.gov.au winter energy savings guidance: thermostat settings, insulation, windows and draught-proofing (checked October 2026).
• Your Home (yourhome.gov.au) heating and cooling chapter: thermostat settings, hydronic pumps and pipes, in-slab heating, and pre-heating on solar or low-cost tariffs (checked October 2026).
• Energy Made Easy, the Australian Government's free energy-plan comparison service.
• Manufacturer datasheets for the heat pumps, boilers, pumps and radiators we install.
• Bureau of Meteorology climate data and the heating degree-day figures we use in heat-loss calculations.
• AHHAC design, install and service experience across 2,400+ hydronic systems since 1998.

Every tariff and annual figure here is an illustrative example calculated from the stated assumptions — not a quote, forecast or measured result. Written and reviewed by the AHHAC Technical Team — licensed plumbers and hydronic engineers (NSW Lic 262528C). We'll review the example rates before winter 2027.