---
title: "What is hydronic heating? A homeowner's guide to how it works"
date: 2024-12-20T15:26:00+11:00
author: Geoff Pennington
canonical_url: "https://sogeo.com.au/blog/understanding-exactly-how-hydronic-heating-systems-work-the-basics-for-homeowners"
section: Pages
---
<!\[CDATA\[YII-BLOCK-BODY-BEGIN\]\]> - [ About ](https://sogeo.com.au/about-us)
- Systems Toggle Systems submenu
- [ Ground Source Heat Pumps ](https://sogeo.com.au/ground-source-heat-pumps)
- [ Air Source Heat Pumps ](https://sogeo.com.au/air-source-heat-pumps)
- [ Hydronic Heating & Cooling Specialists, Melbourne ](https://sogeo.com.au/hydronic-heating-cooling)
- Solutions Toggle Solutions submenu
- [ Commercial & Multi-Residential Hydronic Heat Pump Systems ](https://sogeo.com.au/commercial-multi-residential-hydronic-heat-pump-systems)
- [ Case Studies ](https://sogeo.com.au/case-studies)
- Resources Toggle Resources submenu
- [ How Geothermal Works ](https://sogeo.com.au/how-geothermal-works)
- [ Replace Your Gas Boiler with a Hydronic Heat Pump ](https://sogeo.com.au/replace-gas-boiler-hydronic-heat-pump)
- [ Underfloor vs Radiators: Which Suits Your Home? ](https://sogeo.com.au/underfloor-vs-radiators-melbourne)
- [ Power-Flushing for Hydronic Heating ](https://sogeo.com.au/power-flushing-hydronic)
- [ Geothermal Drilling Options for Tight Melbourne Sites ](https://sogeo.com.au/geothermal-drilling-options-for-tight-melbourne-sites)
- [ Hydronic and Geothermal Pre-Design Guide for Architects and Builders ](https://sogeo.com.au/architect-builder-guide-hydronic-geothermal)
- [ Blog ](https://sogeo.com.au/blog)
- [ FAQs ](https://sogeo.com.au/faqs)
- [ Contact Us ](https://sogeo.com.au/contact-us)
![SóGeo hydronic heating Melbourne]()
# What is hydronic heating? A homeowner's guide to how it works
If you’re researching hydronic heating for the first time, you’ve probably noticed it comes with its own language - emitters, manifolds, weather compensation, flow temperatures, heat-loss calculations. This guide answers the questions homeowners actually ask, in plain English, so you can decide whether a hydronic system is right for your home.
SóGeo designs and installs hydronic systems across Melbourne, and these are the answers we walk every prospective client through before any quote is given.
If you’re researching hydronic heating for the first time, you’ve probably noticed it comes with its own language, emitters, manifolds, weather compensation, flow temperatures, heat-loss calculations. This guide answers the questions homeowners actually ask, in plain English, so you can decide whether a hydronic system is right for your home.
SóGeo designs and installs hydronic systems across Melbourne, and these are the answers we walk every prospective client through before any quote is given.
## What is hydronic heating?
Hydronic heating is a method of warming a home using heated water rather than heated air. A central appliance, usually a heat pump in a modern system, or a gas boiler in older systems, heats water and circulates it through a sealed loop of pipes to emitters in each room. The emitters release the heat into the room: panel radiators on walls, underfloor pipework embedded in the slab or screed, or low-profile fan-coil units. The water then returns to the heat pump to be reheated, and the cycle repeats.
The fundamental difference from a ducted reverse-cycle air conditioner is the medium. Water carries roughly 3,500 times the heat of the same volume of air, which is why hydronic systems can deliver consistent, room-by-room warmth at low electrical input. Hydronic heating runs silently, doesn’t move dust or allergens through ductwork, and holds its heat in the building’s thermal mass for hours after the heat source cycles off.
## How does hydronic heating work?
A hydronic heating system has four working parts: the heat source, the circulation loop, the emitters, and the controls. Each plays a specific role in the cycle.
The heat source heats water to a target flow temperature, typically 45 to 55°C for a heat pump system, higher for an old gas boiler. A circulator pump moves the heated water through insulated piping into each zone of the house. The water passes through whichever emitters are installed in that zone, radiators, underfloor loops, or fan coils, releasing its heat through the emitter surface. The cooler return water flows back to the heat source through the return leg of the loop, and the heat source reheats it before sending it out again.
A thermostat in each zone communicates with the heat source and the pump, calling for heat when the room temperature drops below the setpoint. In a well-designed system, a weather-compensation control modulates the flow temperature based on the outdoor temperature, running hotter water through the system on the coldest days, cooler water on milder days. This is the single biggest efficiency lever in hydronic design and a SóGeo specialty.
Because the entire loop is sealed and runs at low pressure, a hydronic system operates silently and doesn’t lose heat into wall cavities or roof spaces the way ducted air does. The only moving part is the pump.
## The main components of a hydronic heating system
A SóGeo hydronic install typically includes the following components, each sized during the design stage to match the home’s heat-loss calculation.
The heat pump is the modern heart of the system. An air-source heat pump draws thermal energy from the outside air using a refrigerant cycle; a ground-source heat pump draws it from a borefield or ground loop in the soil beneath or beside the property. Both deliver three to five units of heating for every unit of electricity consumed, which is the efficiency multiplier (coefficient of performance, or COP) that makes hydronic heat pumps so cheap to run.
A buffer tank or low-loss header sits between the heat pump and the emitter loops, smoothing the temperature delivery and giving the heat pump longer, more efficient cycles. The circulator pump moves water around the sealed loop; a manifold distributes flow into each zone independently. Inside each room, the emitters do the actual heating, radiators, underfloor pipework, or fan coils, depending on the layout and aesthetic preferences. Controls and a thermostat in each zone tie the system together and respond to weather compensation logic.
All SóGeo equipment is EHPA-certified to European Heat Pump Association standards, with annual maintenance scheduled to keep the system running at design COP across its 15- to 20-year service life.
## Types of hydronic emitters: radiators, underfloor, and fan coils
The emitter is what you actually see and feel inside the room — and the choice between radiators, underfloor heating, and fan coils is mostly about layout, comfort preference, and the construction stage of the home.
[Hydronic radiators](https://sogeo.com.au/hydronic-heating-cooling/hydronic-radiators-stylish-energy-efficient-heating-for-your-home) are wall-mounted panels, available in standard white or designer finishes. They warm up quickly, are easy to retrofit into an existing home, and offer the most flexibility for room-by-room temperature control. Most [boiler-to-heat-pump replacement](https://sogeo.com.au/replace-gas-boiler-hydronic-heat-pump) projects retain the existing radiators where the heat-loss calculation confirms they’re correctly sized for the new flow temperature.
[Hydronic underfloor heating](https://sogeo.com.au/hydronic-heating-cooling/hydronic-underfloor-heating-comfort-efficiency) buries the pipework in the slab or screed beneath the floor finish. The entire floor becomes the emitter, delivering radiant heat from below at low temperature. It disappears visually, frees up wall space, and produces the most even temperature profile in the room. Underfloor is best specified at new-build or major-renovation stage, but retrofit-friendly systems are available for existing slabs.
Hydronic fan coils combine a small water-to-air heat exchanger with a quiet internal fan, mounted in a discrete bulkhead or wall console. They deliver heat (and in cooling-capable systems, cooled air) faster than a radiator, useful for rooms with high occupancy or rapid-response needs.
SóGeo sizes and specifies emitters during the heat-loss calculation, typically a mix of underfloor in the living areas, radiators in the bedrooms, and fan coils where targeted output is needed.
## Hydronic heating vs ducted reverse-cycle: which is right for you?
The most common alternative to hydronic heating in a Melbourne home is a ducted reverse-cycle air conditioning system. Both are electric, both can heat and cool, and both can be efficient, but they deliver very different comfort, running cost, and longevity profiles.
A ducted reverse-cycle system pushes heated or cooled air through sheet-metal ducts in the roof space, then out through ceiling registers in each room. It heats fast, cools fast, and the ductwork is comparatively cheap to install during a new build. The trade-offs are noise (the indoor fan unit runs whenever the system is on), uneven room temperatures (rooms at the end of long duct runs warm last), heat loss into the roof space, and a shorter equipment lifespan (typically 8 to 12 years before refrigerant or compressor replacement).
A hydronic heat pump system distributes warmth via water through small-diameter pipework. It heats and cools quietly, holds heat in the building’s thermal mass after the heat pump cycles off, delivers radiant comfort that doesn’t dry out the air, and runs for 15 to 20 years on the heat pump and 50+ years on a geothermal ground loop. The trade-offs are higher upfront cost (typically twice the install cost of a ducted system in a comparable house) and slower temperature response from cold-start.
For homes where the priority is silent, even, radiant comfort over decades, particularly homes replacing a failing gas boiler or building new, hydronic heating wins on lifecycle. For homes where the priority is fast retrofit at the lowest upfront cost, ducted reverse-cycle is the simpler answer.
## How much does hydronic heating cost to run in Melbourne?
A hydronic heat pump system runs at a coefficient of performance (COP) of three to five, meaning every kilowatt-hour of electricity delivered to the heat pump produces three to five kilowatt-hours of usable heat in the home. Against current Victorian electricity tariffs of 25 to 35 cents per kilowatt-hour, that puts the cost of heat output at 5 to 12 cents per kilowatt-hour, depending on outdoor temperature and system design.
For comparison, gas heating in Melbourne typically costs 12 to 18 cents per kilowatt-hour of heat output at current gas tariffs, with the gap widening every year as gas network charges increase. A correctly designed hydronic heat pump system reduces a typical Melbourne home’s annual heating bill by 30 to 50 percent versus an equivalent gas system, with the savings compounding over the system’s 15- to 20-year service life.
Installation cost is a separate question, see our [cost guide](https://sogeo.com.au/blog/how-much-does-it-cost-to-switch-from-gas-to-hydronic-heat-pumps) for current SóGeo pricing on boiler-to-heat-pump replacements and new hydronic installs.
## When does hydronic heating make sense?
Hydronic heating is the right choice for three specific Melbourne home scenarios.
The first is replacing a failing gas boiler. Most Melbourne homes built between the 1970s and 2010s have a gas boiler at the end of its service life right now , if yours is over fifteen years old, leaking, or noisy, the next service visit is likely to recommend replacement. Replacing it with a hydronic heat pump retains your existing radiators (in most cases) and cuts running cost meaningfully from day one.
The second is a new build or major renovation. The decision to specify hydronic at the design stage unlocks the most efficient options, underfloor heating embedded in the slab, ground-source heat pump with a borefield, weather-compensation controls integrated with the building automation. New-build hydronic is the gold standard for whole-of-life comfort and operating cost.
The third is any home where the homeowner specifically values radiant warmth, silent operation, low allergen circulation, and a system designed to run for two decades or more. Hydronic isn’t the cheapest answer up front. It is the answer with the lowest lifetime cost and the highest comfort-per-dollar in a Melbourne climate.
If you’re not in one of these three scenarios, for example, if you’re retrofitting a small apartment where ductwork is impossible and the priority is fast cooling, a high-quality split or multi-split reverse-cycle system may be the more sensible choice.
## Learn more about hydronic heating from SóGeo
SóGeo is a Melbourne-based hydronic specialist. Director Darren Burch has been installing hydronic systems for over twenty years, drawing on three generations of hydronic experience from Ireland.
If you’d like to take the next step:
For a full overview of SóGeo’s hydronic heating and cooling service in Melbourne, see our pillar page on [hydronic heating Melbourne](https://sogeo.com.au/hydronic-heating-cooling).
For full installation pricing detail, see our [cost guide for switching from gas to hydronic heat pumps](https://sogeo.com.au/blog/how-much-does-it-cost-to-switch-from-gas-to-hydronic-heat-pumps).
For more on the heat pump itself, see our page on [air-source hydronic heat pumps](https://sogeo.com.au/air-source-heat-pumps).
For service, boiler-replacement, or retrofit enquiries, see our [boiler-to-hydronic-heat-pump replacement page](https://sogeo.com.au/replace-gas-boiler-hydronic-heat-pump).
Or [contact SóGeo](https://sogeo.com.au/contact-us) directly for a site visit and fixed quote.
01
![SoGeo Team At Work]()
SóGeo designs and installs hydronic heating systems across Melbourne. If you’d like a fixed quote for your home, the next step is a site visit and a heat loss calculation.
Every install starts the same way. We come to the property, measure heat loss room by room, walk through your goals for the system, and write a fixed quote against the design. No estimates, no surprises, no pressure.
For a deeper read on what’s involved before quoting day, visit our pillar page on [hydronic heating Melbourne](https://sogeo.com.au/hydronic-heating-cooling). For installation pricing detail, see our [cost guide](https://sogeo.com.au/blog/how-much-does-it-cost-to-switch-from-gas-to-hydronic-heat-pumps). For boiler replacements and retrofits specifically, our [boiler to hydronic heat pump replacement page](https://sogeo.com.au/replace-gas-boiler-hydronic-heat-pump) covers the most common scenario we see in Melbourne homes.
[SóGeo designs and installs hydronic heating systems across Melbourne. If you'd like a fixed quote for your home, the next step is a site visit and a heat loss calculation.](https://sogeo.com.au/contact-us)
## Our Partners
[  ](https://www.reece.com.au/) [  ](https://www.stiebel-eltron.com.au/) [  ](https://www.mitsubishielectric.com.au/) [  ](https://www.purmo.com/au) [  ](https://www.viessmann.com.au/)
<!\[CDATA\[YII-BLOCK-BODY-END\]\]>