Energy efficiency in constructive parameters

When we talk about energy efficiency, we ask ourselves a question: how do you know if your building or your house is energy efficient?

In the energy efficiency of buildings and dwellings, many factors are involved, all related to the energy and comfort that we have in them, such as heating, hot water, ventilation, lighting,… in such a way that We can say that a building is efficient when it is within some parameters known as energy classification, parameters that indicate the level of efficiency of the House.

The strong impact of the construction sector in Spain leads to the saving of energy in this sector as one of the main challenges in limiting emissions and energy dependence on the outside.

As a data to raise awareness, it is necessary to emit 50-85% less CO2 to the atmosphere before 2050, to limit the increase of the average global temperature to "only" 2-2.4 º C, according to the intergovernmental Panel of Experts on climate Change of the United Nations Ipcc. In this sense, climate change, once it has been verified, forces the energy to be as sustainable as possible to reduce greenhouse gas emissions, GHG. According to the World Meteorological Organization (WMO), the average temperature of the world's surface has risen 0.74 º C since the beginning of the 20th century, and 0.18 º C in the last 25 years. An increase in the average temperature above 2 º C, means that more can be given: droughts, hurricanes, floods, Conriadas, etc.

The main objective of the bioclimatic architecture is to make an efficient use of energy and resources, guaranteeing comfort conditions and environmental sustainability. The PassivHaus standard is a good example of this, whose certified buildings manage to reduce the demand for heating and cooling to values less than or equal to 15kWh/m² per year. Building and rehabilitating buildings in a way that works autonomously, reducing their energy dependence, is possible through the application of effective measures and appropriate legislation that allows it.

The objective of a building designed and built with bioclimatic criteria is energy saving, being able to even become self-sufficient energetically. In any case, a building whose design and construction has been cared for and regulated by bioclimatic techniques can achieve a conventional energy savings of up to 60% without overcosting the construction price and without implying an aesthetic condition That affects the final image of the project. Among the aspects inherent to sustainable design, it is necessary to take into account the distribution of spaces, considering bioclimatic considerations, energy saving and functional. It is worth noting the importance of a good orientation with glazing to the south, with walls and floors of high inertia and stays of little use to the north: Garages, pantries, etc

The orientation is an important factor when it comes to projecting a space, this will determine the solar capture through the windows. In general, in housing it is interesting to capture more energy, because it helps to reduce heating consumption in winter. During the summer it is necessary to limit this radiation by means of shading elements or other techniques so that the demand for refrigeration is not triggered. In buildings destined to offices it is necessary to look for the configuration that guarantees a good natural illumination but that does not trigger the demand of refrigeration. The main guidelines are as follows:

• North Orientation: Never gives the sun and there is the same light throughout the day, though scarce. It corresponds to the coldest part of the house.
• South orientation: In winter by the inclination of the earth gives the sun many hours throughout the day, while in summer it does not give directly to the facade, but above, in this way the facade of the House does not overheat.
• East Orientation: Receives radiation tangentially and obliquely in the early hours of the morning.
• West Orientation: The facades with this orientation also receive tangential and oblique radiation but in the late hours of the afternoon. As in these last hours the ambient temperature is much higher than in the first hours, the thermal effect is overheating, especially in the summer months.

But do we know how the energy efficiency of a building is calculated?

When calculating the energy efficiency of a building, one must take into account a main energy indicator and several complementary.

The main energy indicator to be taken into account for this calculation will be given by two parameters mainly:

• Annual CO2 emissions, expressed in kg per m2 of useful area of the building.
• Annual primary energy, in kWh per m2 of useful surface of the building.

But what can we do to help sustainability and improve the energy efficiency of our homes?

1. Reduce energy demand 

improving housing isolation; A suitable thermal insulation of facades, roofs, ceilings… will produce a lower demand for heating and air conditioning by avoiding the loss of cold and heat of the house. You can read our article: How to improve the isolation of your home. It will also be important to use carpentry and glass suitable for each climatology. You can read our article: PVC or aluminum? Renew your Windows without fear!

Use adequate ventilation systems; It is essential in a house to use adequate ventilation systems that guarantee the quality of the indoor air. The use of intelligent ventilation systems will improve the energy efficiency of our house.

2. Use installations with maximum energy efficiency.

renovation of thermal installations; Replace heating and air conditioning systems with more efficient ones such as systems that integrate condensation boilers, heat pumps, etc.

3. Use renewable energies 

Use renewable energies; The use of solar thermal energy for the production of domestic hot water or the use of photovoltaic solar energy systems for the generation of electricity or systems such as geothermics or the Airthermy will allow us to improve the efficiency of the systems of Air conditioning and at the same time reduce CO2 emissions. You can read our article: Airthermy: Efficient air conditioning. The energy of the future. 

Introduce measurement and control systems; The use of measuring devices and control of air-conditioning and ventilation systems such as digital thermostats, airquality probes, valves or cost departors will facilitate the optimum functioning of the installations, Therefore, in greater efficiency by adapting at all times to the user