Overview

• heating and hot water supplied by a hybrid air-source heat pump
• energy supplied by rooftop solar and battery storage
• all aspects of the house energy infrastructure monitored and automated through a local home assistant server

Heating & hot water

• Heating is provided through a Daikin Altherma 8kW hybrid heat pump (which combines an electric heat pump heating system with a gas boiler). 
• This feeds radiators throughout the home, keeping the house at a constant 20.5˚C
• The Heat Pump also heats the hot water tank, providing the house with hot water.

Solar

• We also fitted a 6.4kW solar array on the roof, paired with a 5kWh battery. 
• This means we operate almost entirely off-grid between May-September each year - even charging the car with solar.
• Excess power is exported to the grid, for which we get paid about £600 a year (depending on production)

Electric car

• We run and charge an electric car from the house, using a Zappi v2 charger.
• This runs off solar most of the time. When it's sunny, solar powers the house first, and then excess power is automatically fed into the car (and if the car doesn't need it, it's fed into the grid, for which we get 15p/kWh)

Controlling everything

• The house's heating, hot water, car charger, solar, battery, and energy consumption is monitored and controlled by a (tiny) local home assistant server in the downstairs utility cupboard.
• This lets us monitor everything going on in the house, on the roof, in the heat pump, and in the car, from our phones.
• Over the last three years we used this to incrementally optimise the heat pump's operation and solar / battery integration, further reducing the house's electricity consumption by 40% and gas consumption by 20% from already low starting levels. This was with no loss of comfort or sacrifice of functionality.