Have you ever asked yourself what will happen if the mankind spends all the sources of energy? Can we, ordinary people, do something to reduce the consumption of these precious resources? Certainly, we do. We can change our habits in order to save our money, to save the Planet and to slow down climate changes. Some recommended habits that the population should practice are to use public transport, to buy smaller and energy-efficient cars, to turn off household appliances that are not used in a given time or to purchase energy efficient appliances (marked with A). Due to the fact that buildings consume a lot of energy, there are projects that encourage people to build energy-efficient houses.
To put it simply, energy efficient house is a house that operate with less energy than a normal house. Decreasing of energy consumption and achieving the best possible utilization of available energy is not an old concept. People have always been concerned about the getting warm houses in winter and cold houses during summer. This idea was first studied and recorded nearly 2,500 years ago. A Greek philosopher, Socrates planned and described the first energy-efficient house. The basis of his researching was the impact of movements of the sun to the position and shape of home construction. The ground plan of this kind of house was a trapezoid with a south-facing base and a roof that fell to the north to reduce the impact of the strikes of northerly winds. The north wall was a massive structure, and the porch, which was south oriented, was designed to protect from sunshine during summer, and at the same time to let the low rays of winter sun to enter the house. According to this concept, houses in the northern hemisphere should be south-facing, and in the southern hemisphere north oriented to maximize solar energy. There should be very well insulated walls on the other side of the house, to prevent energy loss.
There are five major categories of energy-efficient houses:
1. Low cost houses (low energy house)
2. Passive houses (passive house, ultra-low energy house)
3. Zero-energy houses (or net zero energy house)
4. Autonomous houses (autonomous building, house with no bills)
5. Houses with excess energy (energy-plus-house)
Low cost houses (low energy house)
These kind of houses tend to reduce and limit the energy consumption for space heating. Because of the different climates, in each country these limits are not the same. As it should be supposed, in warmer areas the amount of energy spent on heating is lower.
The constructors build these houses with high levels of insolation, put energy efficient windows so there is a low level of air leakage. One can also use the technology to recycle heat from water that is used for showering or from the dishwasher.
Passive house (passive house, ultra-low energy house)
In the passive house fresh air is subsequently heated or cooled and the quality of air inside the house is high. There is no need to the additional recirculation of air. The amount of energy that is spent on heating should not be higher than 15kWh/m2. Thus, people who live in this type of house use from 75% to 95% less energy. This number is really breathtaking. Today, the cost of building passive houses is significantly lower than it was in the past. This is due to development of technology and to the increasing competitiveness of products designed specifically for the construction of passive houses.
Home zero energy (zero-energy house or net zero energy house)
A zero energy house is a house that function without consuming energy at all, it is independent from the power grid. However, there are periods of year when some low energy consumption is inevitable. Surely, in other periods this energy is returned to the power grid. These houses have many beneficial effects also to the environment, because they generate the energy through renewable sources. As we know, renewable energy sources emit very little greenhouse gas emissions.
Autonomous home (autonomous building, house with no bills)
An independent-autonomous house is designed to normally operate independently from infrastructural support from the outside. Therefore, there is no connection to electricity distribution, water supply, sewerage, drainage, communication network, and sometimes there is no connection to public roads.
Houses with excess energy (energy-plus-house)
House with a surplus of energy is a house that throughout the year makes more energy using renewable sources of energy than is taken from other systems. This is acquired by synthesis of small generators of electricity and low-energy building methods. There are examples that energy-plus houses sell their excess power to companies for distribution of electricity.
As we said in the beginning of this article, energy is something that should be protected and saved for the future generations. By means of building energy-efficient houses, tomorrow our descendants will be very grateful because of the protected environment and energy resources.