"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."

For Sydney's mild winters and warm summers, a reversible hydronic heat pump is the smart choice: gentle radiant warmth in winter and silent chilled-water cooling in summer, from one all-electric unit that runs on rooftop solar. Designed and installed across Greater Sydney from our Punchbowl showroom.
Heat pump hydronic heating in Sydney uses one reversible, all-electric outdoor unit to warm water for underfloor or radiators in winter and chill it for silent cooling in summer. Sydney's mild climate, about 700 heating-degree-days a year, keeps a Maxa i-290 or i-32V5 running at a seasonal COP of 4+, so running costs are very low, especially with rooftop solar. AHHAC sizes every system from a room-by-room heat-loss calculation and installs from our Punchbowl showroom.
Reviewed by the AHHAC Technical Team — licensed plumbers & hydronic engineers, NSW Lic 262528C.How we write & review

ImmergasSimeThermaSkirt™A hydronic heat pump is, for most Sydney homes, the best heat source you can choose. Sydney's climate is mild — roughly 700 heating-degree-days — which means a well-sized heat pump barely has to work to keep a home warm, and it runs at a seasonal COP of 4 or more: every kilowatt of electricity becomes four-plus kilowatts of heat. It's all-electric, gas-free and pairs perfectly with the rooftop solar so many Sydney homes already have, pushing daytime running cost close to zero. And because it's reversible, the same unit cools the house in summer — heat and cool from one machine. AHHAC designs and installs heat-pump hydronic systems across Greater Sydney from our Punchbowl showroom, part of our wider hydronic heating Sydney service.
The heat pump is the plant; the emitter is how the warmth reaches your rooms. A Sydney heat pump can drive silent, invisible hydronic underfloor heating for new builds, or fast-response hydronic radiators for renovations and existing homes — often both in the same house. Whichever you choose, the low flow temperatures modern hydronic systems use keep the heat pump in its most efficient band. Explore the range on our heat pump hydronic heating page.
We build Sydney systems around the Italian-engineered Maxa i-290 (R290) and i-32V5 (R32) — quiet, efficient, VIPAC-certified for Australia — and size every job to a heat-loss calculation so the unit is matched to the home, not a rule of thumb.
Sydney's mild winter is the heat pump's friend. Efficiency (COP) is highest when the gap between outdoor and flow temperature is smallest, and Sydney's relatively warm winters mean the i-290 spends the season in its sweet spot, sipping electricity. Over a Sydney winter that translates into very low running cost — and because the unit is all-electric, rooftop solar can cover much of it. There's no gas connection, no combustion, no flue, and no standing charge. For the honest comparison against blown-air systems, see our guide to ducted vs hydronic heating.
A reversible heat pump is two systems in one. In winter it warms water for your underfloor or radiators; in summer it produces chilled water for silent, draught-free hydronic cooling through the floor or through fan coils. For a Sydney home that needs both seasons covered, that's a compelling proposition — one piece of plant, one all-electric bill, and none of the noise or blown dust of a ducted air conditioner. Running cost for the cooling is typically 25–40% below ducted AC.
The heat pump doesn't care which emitter it drives, so the choice is about your home. In-slab underfloor gives the most even, invisible warmth and suits new builds; European panel radiators warm fast and retrofit easily into existing Sydney homes. Many homes blend both. Our comparison of underfloor heating vs radiators lays out cost, comfort, response time and retrofit-ability so you can choose with confidence.
Both are excellent for Sydney. The i-290 uses low-GWP R290 refrigerant, offers the highest efficiency and adds domestic-hot-water and chilled-water functions; the i-32V5 comes in 11 chassis sizes for very precise sizing at a slightly lower cost. For Sydney's mild loads either is a strong choice — we recommend based on your heat-loss figure, whether you want on-board hot water, and budget. Our i-290 vs i-32V5 comparison covers it in full.
Every AHHAC Sydney job starts with a room-by-room heat-loss calculation, so the heat pump is sized to the actual building — an oversized unit short-cycles and wastes money, an undersized one can't keep up on the coldest mornings; our guide to mistakes to avoid explains why this matters. We then design around your solar, deliver a fixed-fee quote within 24 hours, install in-house to AS/NZS standards, and commission with a documented handover. From Punchbowl we cover the Eastern Suburbs, Inner West, Lower and Upper North Shore, Northern Beaches, the Hills and the Sutherland Shire — see our hydronic heating Sydney page for the full service area.
Most of the decisions that make heat pump hydronic heating in Sydney pleasant to live with are made before any pipe is cut, and the biggest one is where the outdoor unit goes. Sydney lots are often tight: narrow side passages on semis and terraces, zero-lot-line townhouses, apartment balconies. So we walk the site with you and agree the location at the first visit, rather than leaving it to the install crew on the day.
We also ask how your household uses hot water. If you want the heat pump to look after domestic hot water as well as heating and cooling, that changes the unit selection and tank size, so it is far better settled at quote stage than added later.
Even small inner-city homes can take a heat pump discreetly. Our Paddington terrace case study shows a compact unit serving a heritage home with no visible plant. If your roof already carries panels, our guide to solar hydronic heating explains how to time heating and cooling around your own generation, and a well-programmed hydronic thermostat handles the schedule from there.
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 heat pump hydronic heating 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.
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"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."