A young engineer has transformed his 1955 top-floor apartment into one that needs no electricity to cool down in summer, while its twin flat next door needs four air conditioners.
As soon as you step into Stefan De Marco’s apartment, housed in a block of six on a very busy road in Birkirkara, you feel a sudden drop in the temperature and humidity levels. It certainly feels comfortable compared to the sticky outdoors… or inside most typical Maltese houses.
“Whenever I returned from a trip abroad I used to wonder why in Malta it never felt as comfortable indoors. It’s either too hot, too cold or too humid.
“So when I bought this apartment, I started thinking of how to insulate different corners and walls to achieve thermal comfort without having to rely on electricity,” he told this newspaper.
The transformation of the apartment, on which work is still in progress, became the topic of Mr De Marco’s master’s dissertation. Together with Prof. Vincent Buhagiar he recently published a University of Malta paper on retrofitting a Mediterranean dwelling into a thermally comfortable and low-energy home.
He started off by removing the paint on the inside walls of his apartment to allow the stone to breath and not store up humidity.
The engineer put a layer of expanded polystyrene across the roof and also insulated some of the walls from the outside with foam boards.
He replaced the apertures with double-glazed ones and installed adjustable blinds on the outside of the windows. Placing blinds outside a window immediately blocks the sun’s rays from entering the house through the window pane.
And despite opposition from his architect colleagues, he sealed all ventilators.
In summer Mr De Marco ventilated the apartment at night and then shaded the place throughout the day by keeping the blinds closed.
The energy–saving measures I used in this apartment can be retrofitted to any existing house
In winter he opened the apertures at noon to allow the warm air in and then trapped the heat indoors.
For a whole year, he monitored the indoor climate of the flat, the common area, its mirror-image apartment and Birkirkara’s microclimate. The results show that the flat managed to keep a constant and very comfortable indoor climate across both the hot and cold seasons.
It was only for a total of nine out of 122 days in summer and 16 out of 121 days in winter that the climate indoors did not fall within the comfort-zone limits.
The flat uses adjustable blinds on the outside and, right, foam insulation.
In fact, he has only had to switch on a fan for a short spell during a heatwave in August, and in winter he never needed a heater.
Mr De Marco did not only manage to reduce his carbon footprint, but in 15 years’ time he will have saved enough money to cover his expenses to adapt the apartment. After that, he will be making a profit of at least €700 yearly.
Had he decided to leave the double-glazed windows out of the equation, which he later discovered he could actually do without, Mr De Marco would have recuperated his expenses in seven years.
He has now started working on an indoor ventilation system that will force out the warm air emitted from kitchen appliances in summer or direct this same heat to the bathroom in winter, so that he does not have to switch on a heater.
By installing an elevated floor under the table, benches and kitchen cabinets, he created a circulating path for the emitted heat that is usually wasted in other homes.
“The current local built environment has a common thermal comfort problem, and most houses rely on electricity for indoor environmental control.
“The feasible energy–saving measures I used in this apartment can be retrofitted to any existing house – and managing to transform my flat, built in 1955, into a minimum-energy home shows that it can be done with any other building.”