Low Energy House Seatoun

Located in Seatoun, Wellington, this high-end family home didn’t only aim to please the eye, but also to be as energy-efficient and environmentally-friendly as possible.

The Goal

The driving force behind the concept and build process of this striking luxury home was to create a house that minimised its energy consumption and environmental impact, and that was built taking into account internationally recognised green construction principles.

With traditional electrical hot water cylinder systems accounting for as much as 28% of a typical power bill, the family was specifically looking for an alternative hot water heating system that was as energy-efficient as possible with a minimal carbon footprint.

The Challenge

The homeowners required a reliable hot water system that could not only provide super energy-efficient hot water for their day-to-day hot water use, but that was flexible enough to also cater for any additional visiting family members. As such a hot water system with quick recovery times was paramount.

As the home is located at the corridor of Wellington Harbour in Seatoun, the area is often hit with salt-laden southerly winds from the Cook Strait. As a result, salty air from the sea has the potential to erode external components exposed to the elements, which can significantly reduce the lifespan of the overall system and its performance. As such, any solution had to be able to withstand these climatic conditions.

The Solution

With maximising energy efficiency in mind, the finished home incorporated highly insulated walls, floor and ceiling, as well as triple-glazed windows. Furthermore, a Mitsubishi Electric Ecodan Hot Water Heat Pump was specifically chosen. Compared to Ecodan Hot Water Heat Pumps, traditional water heating methods such as gas or traditional electrical cylinder systems are not only far less energy-efficient but also have much greater carbon footprints.

Super-Efficient Ecodan Hot Water Heat Pump

An 8.5kW capacity Mitsubishi Electric Ecodan Hot Water Heat Pump System was the natural solution for the daily hot water requirements of this home. The system provides super-efficient potable water with the ability to effectively heat water up to 60℃.

An EHPT20X Ecodan Packaged Cylinder System was chosen that conveniently comes pre-plumbed and pre-wired. This solution incorporates a 200-litre water cylinder and the plate heat exchanger as well as key hydronic components (including pumps, expansion vessel, flow sensor, scale trap and automatic air vent) all in the one package. The system features fast heat-up times through the use of Plate Heat Exchanger Technology that works in conjunction with smart energy monitoring and control.

External Marine Coating to Combat Environmental Elements

A standard with all Ecodan Hot Water Heat Pumps, this system came with a special external coating which reduces the effects of the harsh salty air in the area on the fan coil and PCB boards. As a result, it was ideal for the coastal location of this home.

Built-In Smart Control with Energy Monitoring

The integrated controller offers state of the art energy monitoring and management of the Ecodan Hot Water Heat Pump System. As a result, the homeowners now have the visibility and freedom to efficiently manage their overall water heating power consumption. The daily scheduler enables the family to take advantage of off-peak tariffs, to save even more on their electricity bill.

Built-In Legionella Protection Mode

The controller interface is intuitive and ensures hot water conditions are always safe and sanitary. The Ecodan Cylinder will automatically default to Legionella Protection Mode raising the temperature to eliminate the risk of legionella.

The Result

This house has achieved the homeowner and designers’ goal of being a low energy, low carbon footprint, high-performance home that is warm and dry, all year round. The Mitsubishi Electric Ecodan Hot Water Heat Pump System has now seen its first winter and has performed just as expected, using minimum energy to generate all the hot water the household needs.

The high sustainability credentials with minimum energy use in the home truly make this project a success.

Equipment Breakdown

Ecodan Hot Water Heat Pump
Outdoor Unit

1x 8.5kW PUHZ Hot Water Heat Pump

Ecodan Packaged Water Cylinder and Heat Exchanger

1x EHPT20X 200L Packaged Water Cylinder

Built-In Controller

PAC-IF061B-E Controller (FTC5)


Published: Friday, 8 November 2019


Ecodan Hot Water Heat Pump Showcase
Low Energy House Seatoun