Powerbay

Powerbay is an Australian outfit running out of Parkinson in Queensland with a Victorian office in Cremorne, so warranty and parts are handled onshore rather than through an offshore importer.

The current line-up is the Gen II Inverter, and it's a proper step up from the old single-speed budget units. An AI-controlled inverter compressor matches output to what the house is drawing, a microchannel exchanger wraps the tank, and the whole thing runs on 340 g of R290 natural refrigerant (GWP 3).

Three sizes — 200L, 250L and 300L. The 200L and 250L pull 2.65 kW of heat from 560 W of power, which works out to a COP of 4.73; the 300L sits at 2.35 kW for a COP of 4.2. All three are hybrids with a backup element, so you've got a fallback on the coldest mornings, and the heat pump itself keeps working down to -7°C.

The tank is enamel-lined thick carbon steel with a magnesium anode, tested through 250,000 pulsation cycles and backed by a 5-year replacement warranty — the catch being a 500 kPa pressure limiting valve has to go on the cold inlet, which we fit as standard. There's also a weekly automatic sterilisation cycle that lifts the tank temperature to knock off any legionella risk.