Glass is a poor thermal insulator. In summer when outside temperatures are higher than the desired one indoors heat flows into the rooms mainly through glass doors and windows.
In winter the reverse too applies. A single sheet of glass as found in most facades of commercial outlets, conducts heat about 20 times as rapidly as a well-insulated wall.
If double glazing is used by adding a second glass this rapid heat flow is halved. Further insulation is achieved by adding a thin and transparent glazing sheet and by filling the space between the glass sheets with gas.
Besides conduction, light travels through glass in the form of infrared waves, producing the greenhouse effect, thus further increasing room temperatures. Again, these may be reduced by an improved low e-coating glazing sheet.
With all these improvements you may still end up with insulation that is about 40 per cent as good as a well-insulated wall.
However, there is a further effective improvement which we in Malta, especially at the design and building stage, do not seem to bother about. These are louvered or roller shutters fitted on the outside of the aperture frames.
Roller shutters reduce heat entering the apertures by over 90 per cent and will keep the house warmer in winter by 15 to 20 per cent. They are also effective as sound insulators, in room ventilation, light control and offer better security. In fact, they are fitted as standard in most houses and apartments in southern Europe to minimise heat infiltration in summer while in the north they are mostly useful in winter to minimise heat loss.
A study conducted by the Dutch scientific research institute TNO concluded that nearly 100 million tonnes of carbon dioxide, equal to one third of EU’s emissions reduction target, could be cut annually through the widespread use of low-emission glazing alone.
It would be interesting to have an estimate of the energy savings in Malta if the fitting of shutters outside our apertures was widespread. I would not be surprised that the electrical consumption of air-conditioners would be reduced by well over a third.
Energy-saving requirements of a building should start at the design stage. Although energy performance of buildings falls under the Malta Resources Act it is the Malta Environment and Planning Authority that is primarily responsible for the processing and issuing of permit applications.
The architect in turn is responsible to ensure development is in accordance with relevant Maltese legislation and EU directives and policies.
Throughout the years Mepa has made available revised versions of a Development Control Policy and Design guidance, the last being the DC 2007. Energy saving is dealt with in half a page in Part 13.
At the design stage, where practical, the architect is to take account of the potential of specific energy conservation matters, especially to maximise passive solar design, the use of atria and courtyards for natural lighting and ventilation.
The rest of Part 13 is mostly dedicated to solar water heaters, photovoltaic collectors, water cisterns and water tanks.
There is no mention of policies to reduce heat transfer through apertures, ventilation regulations or methods, sound insulation, health and safety requirements for inhabitants and engineering policies.
As regards water cisterns for rainwater run-off the architect is requested to submit plans of its location with his application. Water cisterns are required by the Code of Police Laws, but then so is ventilation.
There is a clear need for a large dose of other engineering disciplines besides that of architecture. However, Mepa would not discuss policies with me, a professional mechanical engineer, even on ventilation and heat transfer, which are well in my domain, since I was told I am not an architect.
With so many high-rise apartment blocks still under construction and others whose permits have been recently approved I find it very strange that we are looking so lightly at energy-saving policies, such as planning for roller shutters at the design stage.
Other countries are even applying heat recovery systems in ventilation, using equipment that is readily available from air-conditioner manufacturers to save up to 95 per cent of the energy otherwise lost to the environment.
Can Malta really afford to continue to ignore such effective energy saving methods?
Mr Schembri is a retired mechanical engineer.