This home was designed with the goal of being environmentally sound. It is shaped and oriented to maximise the winter sun while avoiding the heat of summer, and most of the time you can choose the temperature by just opening or closing windows. To keep the house warm during the night and cool during the day, the house surrounds a slab of concrete that absorbs the heat of the day and releases it at night. The house is nestled among the trees and rises up just enough to afford spectacular views down on to the nearby bay.

Power is provided by a roof mounted solar grid supported by a generator for occasional use. Usually total consumption is the same as two continually running towel rails. Also on the roof is a solar hot water system. If the sun is behind a cloud, you can light a fire for more hot water and heat in the pot-belly stove that you can also cook on. The power system also has to support the rainwater and sewerage pumps - a challenging load since these pumps are most active when weather is bad and solar power is not available. Without a way to start the generator remotely the house could run out of power if left unattended.

From the start, the barrier house has driven the nexus’s design. The most important requirement is to be able to check power and rainwater status from town. Also important is minimising power use and predicting how long the house can run on solar alone before the generator will have to be used again. The $2 per kWh that it costs in fuel to run the generator far exceeds the 20c per kWh available in town so careful power management pays dividends here. Subsystems such as the satellite based internet connection are switched off when not in use.

From conception, the house was wired for control. Every light switch is individually addressable and every light is under computer control 24/7, accessible via any mobile phone or internet connection. We can monitor power usage, solar power collection and temperatures and will soon add information about water heating and usage. We already know that the fridge, computer, washing machine and vacuum all use the lions share of the power. Over time and with the nexus’s live feedback we learn more and more.

We can choose the level of access we give to our friends via the internet. They can look at our power usage but can’t control the lights, and if they are strangers they can only see time-delayed, low resolution data for privacy. We have complete control over how public or how private we are online and who is able to do what. When we come back from town we know that the batteries are full, the lights are on and everything is ready to go!