Reducing your home's carbon footprint starts with how you heat and cool. Here's how hydronics — paired with the right energy source — beats every alternative.
The most eco-friendly heating and cooling for most Australian homes is a hydronic system driven by an air-source or geothermal heat pump and powered by rooftop solar PV, which brings operational emissions close to zero. Heating and cooling account for about 40% of a home's annual energy use, so this is the biggest decarbonisation lever most households have, and a hydronic network lasts 30+ years. AHHAC designs low-carbon systems in Sydney and across NSW, VIC, QLD & ACT.
Reviewed by the AHHAC Technical Team — licensed plumbers & hydronic engineers, NSW Lic 262528C.How we write & review
Heating and cooling typically account for 40% of a home's annual energy use. Choosing a low-carbon system is the single biggest decarbonisation lever most homeowners have.
The greenest hydronic system today is a heat pump driven by solar PV — operationally near zero-emissions, with a 30+ year design life.
Direct electric resistance: 0.7 kg CO2/kWh (AU grid avg). Gas boiler: 0.21 kg/kWh. Air-source heat pump (COP 4.0): 0.18 kg/kWh. Geothermal heat pump (COP 5.0): 0.14 kg/kWh. Solar-thermal + heat pump backup: <0.05 kg/kWh.
Pair any heat pump with rooftop solar PV and you can reach near-zero operational carbon.
People often come to us wanting the greenest heat source available, but the lowest-carbon home is usually built in a particular order. Spend in the right sequence and each step makes the next one smaller and cheaper.
Not every home needs every step, and some heritage houses cannot take all of them. Where a gas connection is being retired, we plan hot water at the same time so the home can come off gas completely rather than keeping a meter for one appliance. Following the sequence also avoids the most common waste we see: a large, expensive heat pump installed to heat a house that is losing its warmth through the ceiling.
Explore the Maxa i-290 R290 heat pump, heat-recovery ventilation (MVHR), solar hydronic heating and our heat pump hydronic heating guide.
Written from on-site experience by the AHHAC Technical Team.
AHHAC's in-house design and service team — licensed plumbers and hydronic engineers (Lic 262528C) who have designed and installed 2,400+ hydronic heating, cooling and hot water systems across Australia since 1998.
We design eco-friendly heating & cooling from a room-by-room heat-loss calculation, install it with our own licensed plumbers to AS/NZS 3500 (plumbing) and AS/NZS 5601 (gas), commission and document it, and service it for the life of the system. Nothing is subcontracted out.
Air-source or geothermal heat pump driven by solar PV — operationally near zero-emissions, with a 30+ year design life. Solar thermal heating is also excellent. Gas boilers are about 60% lower carbon than direct electric on the AU grid mix; heat pumps are about 75% lower than gas.
For hot water, yes — Small-scale Technology Certificates (STCs) apply to registered heat pump and solar water heaters, and state programs (e.g. Victorian Energy Upgrades, NSW hot water incentives) may add more. Air-to-water heat pumps used for hydronic space heating generally aren't covered. Amounts change, so we confirm eligibility at quote and handle the paperwork.
Yes — solar thermal collectors paired with a wood/pellet hydronic burner and a thermal store can provide year-round heating fully off-grid. We've done this for cabin and rural builds.
"AHHAC delivered our 22-zone underfloor system on time, on budget and to spec. The crew were tidy, the documentation was thorough, and the commissioning was textbook."
"We've worked with AHHAC for 17 years. They've installed and serviced our hot water plant across three commercial buildings — and they pick up the phone on weekends."
"Three mobs quoted us; AHHAC's design was the only one based on a proper heat-loss calculation. The system runs beautifully — the others would've been oversized and expensive."