In 2005, the Housing Authority launched a pilot energy-saving project at Tal-Ftieh, Birkirkara. The aim of the project was to achieve better energy performance in building while promoting innovative measures that make the best possible use of natural resources and do not harm the environment.

Commenting on energy-saving housing, the Chairman of the Housing Authority said: “When we launched this project we wanted it to serve as an example of good practice as well as to save our clients money and energy. Our hope is that this is just the start of a journey, which will result in far more eco homes all over Malta and Gozo, which should become mainstream over the coming 10 years. Obviously we have to win the hearts and minds of clients as well as overcome the financial burden of building to energy-saving standards in the first place, but this project has shown that we can be green, and should continue to be so in years to come.”

The building block in Tal-Ftieh was constructed to include energy-saving features such as double-glazed windows, louvres, roof insulation and 150-litre solar water heaters for each apartment, including pipe insulation.

A study that was recently published at the one-day seminar organised by the Institute for Energy Technology of the University of Malta on 29 January showed that the solar heating systems operating since 2005 at Tal-Ftieh Energy Saving Housing Project have each saved an average of 1,850 kWh of energy and 1.6 tonnes of carbon dioxide every year, excluding the summer period. This implies that the payback period for these systems would be about four years under real operating conditions.

Engineer Charles Yousif of the Institute for Energy Technology of the University of Malta, together with an Erasmus student from Valladolid University in Spain, have carried out an independent study into these solar systems. Support was also provided by Dr Vincent Buhagiar of the University of Malta’s Faculty of Architecture.

Data collected over a period ranging from six months to three years on four systems that were continuously in use by the occupants. Results showed that hot water availability depended very much not only on the correct installation of the solar system but also on the lifestyle adopted by the users. Heavy users of hot water had to switch on their electric back-up heating more often, while prudent users only switched on their back-up heating elements for the first time in December 2007. In fact, this month was exceptional for Malta, with rainfall totalling 206.8 mm, which was more than double the average for the month over the previous 85 years. It was found that average users would expect to switch on their back-up electric heating for a few hours every day for about 15 days a year only.

In winter, the average hot water temperature in the solar tanks ranged between 50 and 60 °C, while in summer, the systems had to be covered by a shading material to avoid over-heating. This routine exercise of covering and uncovering the panels once a year also gave the users an opportunity to check their solar systems for any leakage or other visible defects.

The maximum overnight fall in temperature in the solar tanks was 11°C in winter, but since the overall water temperature was above the 50°C mark, the morning temperature was still quite adequate (around 40°C) to provide sufficient hot water without switching on any electric back-up.

The study also showed that the minimum hot water usage of the occupants was 20 litres/person/day, while a more typical usage would be around 30 litres/person/day for washing needs only. This is the first time that such figures have been published in Malta, based on the long-term monitoring of hot water usage.

Infrared thermal images taken on site showed that the solar tanks and panels had excellent thermal insulation properties and no defective areas were found.

All in all, the solar systems performed very well during the first three years and the only maintenance required on some of them was the replacement of the electric back-up heating element that appeared to have deteriorated due to the combined effect of high temperatures and the salinity of the water.