Natural light, views and style are well-known benefits of windows, glass-facade buildings and curtain walls

However, these openings, sometimes taking up the whole façade of a building, are inevitably weak points when considering the energy performance of the same building. Glazed openings are potential points for excessive heat gains in summer, and heat losses in winter.

Size of openings, orientation, materials to be used and shading devices (internal and external) are all key elements which need to be taken into account when one is designing a building.

Designers are often faced with this dilemma, and reaching a good balance is not always easy. Different climates need different solutions. The main issue in northern countries is heat losses. Solar heat gains are most often welcomed in such countries as these will help in reducing the heat costs.

On the contrary, our geographical position makes Malta one of the warmest states in Europe. Although heating in winter is sometimes necessary, our main challenge is preventing over-heating in summer to reduce the use of air-conditioning.

As such, solutions which are viable in northern countries, most probably cannot be adopted locally. Likewise, materials (mainly glass) which have been developed to provide efficient solutions in northern countries are not necessarily adequate for the local market. Evidentially, there is no one-size-fits-all solution. Identifying our problems better will help us find our solutions rather than trying to adopt other countries’ solutions.

While issues related to orientation and sizes of openings are being taken care of, shading devices are most often forgotten. I still cannot understand how buildings in Brussels, where the sun seldom shines, are equipped with both external and internal shading devices (the European Commission Building is a typical example) and locally such devices are practically inexistent.

In addition to this, the choice of glass for our openings needs much to be desired. Single glazing, used for centuries, started being out-sided by the introduction of the so-called double glazing. However, by today’s standards, double-glazed windows installed some 20 years ago which helped to achieve energy saving at the time, are now considered completely outdated.

Today, we are discussing low – emissivity glass and solar control glass. Low-emissivity (Low-E) glass is specifically treated with a transparent coating reflecting heat back into the building thereby drastically reducing the heat loss through windows. However, the coating of Low-E glass allows free solar energy to enter the building. This may help in passive heating of buildings in cold Nordic countries but definitely undesirable in the local scenario. Investing in Low-E glass locally might not be the best investment one can do. On the other hand, solar control glass is a coated product that reflects and radiates away a large degree of the sun’s heat while allowing daylight to pass through. The characteristics of solar control glass are ideal for countries like Malta as they will contribute to reduce the use of air-conditioning.

Going a step further, i.e. by applying double-glazed solar control glass which will be also Low-E will further contribute to insulate our buildings from both cold and heat, depending on the season. That will be a good investment!

I also feel that it is ripe time for us to review our existing glazed areas more seriously. It is estimated that 45% of all glazed areas in Europe are still single glazed. I don’t know the local percentage, however what I am totally sure of is that it is definitively much higher than 45%. Owners of houses, commercial and industrial buildings should seriously consider the replacement of their apertures. If that sounds too drastic, the application of a solar film to existing apertures may prove to be a good compromise.

However with our air-conditioning units working around the clock almost non-stop and with an active subsidy scheme offered by the Government through MRA, giving a refund of 15% of the eligible cost up to a maximum of €1000 (applicable to domestic buildings), investing in good quality glass now is not a bad idea at all.

Architect Philip Mifsud is a parliamentary assistant in the Resources and Rural Affairs Ministry