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Econergy is a true New Zealand success story, engineered right here to meet our unique climate demands. The THD3500 is their premium split-system solution, widely regarded as one of the most efficient water heaters on the market, specifically designed to thrive in the chilly South Island conditions.
The standout feature of the Econergy system is its split-design flexibility. Unlike "all-in-one" units, the THD3500 heat pump sits outside and connects to a cylinder via pipes. This means you can:
The THD3500 features a patented parabolic heat exchanger that achieves world-class efficiency. In many cases, it can provide up to 75% savings on water heating costs compared to a traditional electric cylinder.
While some heat pumps struggle as the mercury drops, the Econergy THD3500 is rated to operate effectively down to -5°C. Because it uses high-quality components and smart defrost cycles, it continues to harvest heat from the air even on those crisp, frosty Canterbury mornings.
The THD3500 boasts a high thermal output, meaning it can heat water faster than many of its competitors. This high recovery rate ensures that even after a busy morning of showers and laundry, the system bounces back quickly, making it a reliable choice for active households.
Most heat pumps heat the whole tank slowly from the bottom. The Econergy is different—it heats the water and delivers it straight to the top of the cylinder. This means "usable" hot water is available almost immediately. Even if the kids have drained the tank, the unit starts delivering hot water to the shower-head first, so it feels like you have an endless supply.
Choosing Econergy means supporting local engineering. Because these units are designed and manufactured in New Zealand, spare parts are local and the tech support understands our specific water chemistry and electricity grid.
Tim’s Installation Reality Check: Airflow is King
The Econergy unit needs to breathe. When we mount the outdoor compressor unit, we need to ensure there is plenty of open space for air intake and exhaust. If you tuck it into a tiny, enclosed alcove, the unit will recirculate its own cold exhaust air, forcing it to work harder and driving your power bill back up.
Model
THD3500
Heating Output
3.5kW
Installation Style
Retrofit or New
Best For
Families of 2 to 6
Econergy stands behind their Kiwi-built quality with a comprehensive local warranty:
Heat Pump Unit
6 Years
Parts (Excludes Labour)
Cylinder (if supplied)
10 Years
Variable (Manufacturer dependent)
Labour
1 Year
Full Labour Cover
