Retrofitting a Home in Lower Hutt with Radiator Central Heating & High-Temperature Air-Water Heat Pump

The problem

The homeowner had already invested in double glazing and insulation to improve thermal efficiency, but still experienced discomfort during the colder months. The insulation retained heat well but also trapped cold air when the house was not actively heated, making it difficult to maintain a comfortable indoor temperature. The client had tried air-to-air heat pumps and electric column heaters, but found these solutions inconsistent, creating uneven warmth and a draughty environment.

The home’s existing hot water system relied on an electric element-heated cylinder, which was costly to run. With energy prices rising, the homeowner wanted a more cost-effective and efficient solution.

Our recommendation

Flow Heating Wellington proposed a radiator-based central heating system powered by a high-temperature air-to-water heat pump, covering both space heating and domestic hot water. The recommendation offered:

1. Consistent and even heating | the radiator system delivers steady, radiant heat throughout the home, eliminating the draughts and uneven warmth caused by air-to-air heat pumps and standalone electric heaters.
2. Energy efficiency and cost savings | the high-temperature air-to-water heat pump significantly reduces electricity consumption by extracting ambient heat from the air to warm both the central heating system and domestic hot water.
3. Reliable hot water supply | the new system replaces the electric element-based hot water cylinder, reducing energy costs while maintaining a consistent, ample hot water supply.
4. Enhanced comfort | unlike air-based systems, which can create dry air or fluctuating temperatures, the radiator system delivers steady warmth without forced air circulation.

The installation

Flow Heating Wellington installed the radiator-based central heating system and high-temperature air-to-water heat pump into the existing Lower Hutt home, working with the home’s existing insulation and double glazing rather than replacing it.

The result

Following the installation, the homeowner reported a dramatic improvement in their living conditions. The home maintained a steady, comfortable temperature throughout winter, with no draughts or cold spots. Running costs for both heating and hot water also decreased, thanks to the efficiency of the air-to-water heat pump.

Heating a Lower Hutt home

This retrofit was completed on an existing residential home in Lower Hutt, part of the wider Wellington region Flow Heating services. Combining the home’s prior insulation and double glazing with a radiator central heating system and high-temperature air-to-water heat pump gave the homeowner year-round comfort without the draughts and running costs of the previous setup.