In general, the recommendations for energy efficiency in this household were as follows [3]:

• Repair of the freezer & fridge-freezer that had faulty thermostats. Installation of a timer switch would also help remedy this fault, if the thermostat cannot be replaced. Estimated electricity savings would amount to 12%. The purchase of new, more energy efficient appliances is another option.

• Use of air-conditioning units for heating in winter rather than electric filament heaters.

• Water consumption — replace washing machine with Class A machine. Change habit of washing patios with free flowing water (Estimated water savings: 40%).

• Appliances in stand-by mode — Switch off appliances that are rarely used (Estimated electricity savings: 7%).

• Install more energy saving bulbs.

For the SWH system, the recommendations were the following:

• Due to the evidence of rusting of the solar tank and some water leakages, one would recommend the eventual replacement of this SWH with two units. The first would be dedicated to the bathrooms; the second would supply the washing machine and the kitchen, thus reducing the amount of water to be heated by the electric backup heater.

• An electrical timer should be installed on every back-up electric element of solar heaters. This would avoid unnecessary heating and was proven to save approximately 12% of the electricity bill over the measured period.

• Clothes should ideally be washed later on in the day; by which time the SWH would have absorbed sufficient solar energy.

• Good insulation on all hot water pipes was also recommended.

One of the salient overall conclusions that may be drawn from this exercise was that the installation of RE systems was, in itself insufficient to ensure energy savings and user satisfaction. A good understanding of the requirements and the lifestyle of consumers planning to install such systems is paramount, to ensure that systems are adequately sized to meet the demands on a case-by-case basis. On the other hand, people using such systems should be aware of the basic operational characteristics, in order to adapt their lifestyles in a way that will give them the full benefits of a renewable resource.

2. Acknowledgements

The authors wish to acknowledge the opportunity given by the homeowners to carry out a detailed energy audit for their home.

References

[1] Enemalta Corporation (2008), Private Communication with Enemalta Corporation, Marsa, Malta.

[2] National Statistics Office (2008), Energy Consumption in Malta 2000-2007, NSO News Release No. 91/2008, 22 May 2008, http://www. nso. gov. mt/statdoc/document file. aspx? id=2244, National Statistics Office, Library & Information Unit, Lascaris, Valletta VLT 2000, , Malta.

[3] M. Villameriel Tejedor (2008), Energy Study at a Residence in Malta, unpublished Final-Year Industrial Engineering Dissertation, Institute for Energy Technology, University of Malta, Malta, in collaboration with Valladolid University, Spain under the Erasmus student-exchange European Programme 2007/08.

[4] M. Krarti (2000), Energy Audit of Building Systems — An Engineering Approach, ISBN 0-8493-9587-9, CRC Press LLC, U. S.A.

[5] S. P. Borg, C. Yousif & R. N. Farrugia (2005), Investigation of Domestic Solar Water Heating Installations in Malta, “Renewable Energies in Malta and Beyond” Seminar, 19 September 2005, Salina, Malta, published by the Institute for Energy Technology, University of Malta, Malta.

[6] J. Gordon (Editor, 2001), Solar Energy: The State of the Art, ISES Position Papers, ISBN 1-902916-23-9, James & James Science Publishers Ltd.