Repsol YPF

Daily activities in Spanish homes are responsible for 25% of emissions of greenhouse gases, almost as much as vehicle transport of goods and passengers (27%), and not much behind that of industrial pollution (34%). The Institute for Energy Saving and Diversification (IDAE) estimates that the energy consumed in private homes, including their vehicles, produces 67.5 million tons of CO2 per year, or about 5 tons per household.Increasing efficient energy saving practices for electricity, gas and other fuels, together with constructing more energy-efficient buildings, has become a central theme of sustainable development. Waste reduction will not only benefit our household budget, but is environmentally friendly as well. 

Good insulation can save up to a 40% in heating costs, or about 160 euros a year per household, as well as considerable amounts in air-conditioning costs, according to IDAE estimates. Insulation also makes a house more comfortable by reducing ambient noise. 

Numerous studies have confirmed that installing insulation during construction in the walls and roof, using doubled paned windows, draft stoppers in doors and windows, curtains on windows, and insulated Persian blinds, results in long term savings. These techniques are considered passive energy savings. 

Using these passive energy saving techniques along with an efficient placement of the house to take advantage of natural sunlight, shade and air currents, can produce a savings of up to 60% as compared to a normal house. 

When insulating a house, it is worthwhile to understand where insulation would benefit the most: first, the roof, then the walls, and finally the floor.  It is well worth it to install double paned windows or double windows, and check that doors and windows all close and seal properly. Any cracks in the walls or ceilings obviously should be filled to avoid heat loss. Hot water tubes and tanks should also be insulated to keep their heat in. 

It is only common sense, but keeping windows or doors open while the air conditioner or heater is on, is simply wasteful. Ten minutes a day of ventilation is enough to keep the air inside a house fresh. 

Another simple saving technique is installing a thermostat on the heating system. Keeping the house temperature at 20º C in the winter is comfortable. Also, turn off radiators in any rooms that are not being used. Finally, wearing appropriate clothes for the season, even indoors, means you can avoid excessive use of the heaters or air conditioners. 

The heating fuel you use depends on a study of each house. Propane or natural gas produces half CO2 levels, but diesel fuel is sometimes more practical and slightly cheaper.  Check the boilers each year to ensure that they are working efficiently. This is another frequently forgotten form of passive energy saving. 

Another simple saving technique is to keep the water heater set at 55-60º C. At this temperature you can use the water directly, without having to heat it so high that it needs to be mixed with cold water before use. Single handle taps with temperature settings further help in saving energy and water. 

A houses best friend in the winter is the sun. During the cold months, try to let as much sunlight as possible enter the house. But in the summer the reverse is true. To keep out the heat in summer, Persian blinds, curtains, and awnings are all useful to keep the sun at bay.  Broad leafed trees on the south side of a house offer the best of both seasons. They give shade in the summer keeping a house cool and saving on air conditioning, but in the winter when they lose their leaves, more sun is allowed to pass. In the hottest months, it is a good idea to keep the windows closed during the day, but open them in the evening to allow cool breezes to refresh the interior. 

Natural lighting is beneficial any time of year. Walls, ceilings and furniture which are light coloured reflect and distribute natural light the best. 

When heating or cooling a small space, or a place where only one person is staying, a bathroom, for example, a small heater is enough. In summer, a fan is much more economical than air conditioning, and is usually good enough. 

When an air conditioner is installed, make sure that it is placed in a shaded area. It is more efficient to start it up before the building gets too hot. Keep the filters clean, and follow the instructions. Cooling systems that use evaporation are cheaper to operate and do not emit any ozone-depleting gases. In all cases, for an air conditioner or any other appliance, it is recommended to choose an energy efficient model which is suitable for the house. 

In the case of a refrigerator, the volume is important. To work best, a refrigerator should be at least two-thirds full. A freezer also works best when it is three quarters full.