This project demonstrates what the latest energy-efficient technology can achieve - a house with ZERO energy bills!
The property is a flat-roofed, 3-bedroom terraced house for a family of four. There was previously a gas boiler for hot water, with typical bills of around €70 per month. Electricity bills were typically around €100 per month. We installed 20 photovoltaic (PV) panels on the rooftop terrace, generating approx 25kW electricity per day. This power is bought by EDP at a rate of around €0,38 per kW, earning a monthly income of approx €285. In addition a thermal solar system was installed for domestic hot water, replacing the gas boiler. This has an electric back-up for times of insufficient sun but is rarely required.
Now, the net gain from income (from electricity generated) against expenditure (electricity consumed) means that the house not only has NO energy bills, but earns surplus revenue – in this case covering its monthly condominium fee!