New buildings - energy efficient construction.
The standards of the required thermal insulation of buildings, set by the legislation, constitute the indispensable minimum. These regulations ensure that the sanitary requirements in the building sector are fulfilled (e.g. not letting mould be grown, and ensuring sufficient ventilation), rather than enabling the house owners and residents to reduce their heat expenses. Therefore only so-called “energy efficient houses” are economically justified.Through implementation of proper technical solutions the heat demand in energy efficient buildings is lower compared to the obligatory legal standards. Depending on the rate of heat demand for space heating the energy efficient buildings are classified as follows:
| Heat demand for building heating: | |
| Regular energy efficient buildings | Not more than 70% of standard heat demand |
| Low-energy buildings | Not more than 45% of standard heat demand |
| Passive buildings | Not more than 30% of standard heat demand |
Future building solutions
Possibilities to lower the energy use for heating do not end with passive buildings. Currently, efforts are undertaken to design houses, which, if the yearly balance is considered, do not use energy from external sources at all, except renewable energy sources like energy from solar radiation, biomass, biofuels, or wind energy. There are two categories of such buildings:
| Heat demand for building heating: | |
| Zero-energy buildings 1 | Energy self-sufficient buildings |
| Plus-energy buildings 2 | Buildings with positive energy balance |
1 Zero-energy buildings per saldo do not take energy from external sources, except for renewable energy like biomass or biofuels.
2 Plus-energy buildings are the buildings of positive net energy balance, meaning that more energy is produced than is used over the year time period.
If the walls are insulated in the internal building space to the same extent that a vacuum flask does, then the energy for space heating, usually harvested from external sources, wouldn’t be necessary any more. The required amount of energy could be delivered by the usual activity of inhabitants (such as cooking, warm water consumption, metabolic processes, mechanical household appliances etc.). This idea has been used in the so-called zero-energy houses. This is by far the most advanced concept of energy consumption reduction in buildings. Although, with current energy prices, its realisation is still not fully profitable, the attractiveness of such concepts increases as the energy prices increase rapidly. Whether economic or not in today’s climate, this idea tempts peoples’ imaginations and some demonstration houses have already been built. Who knows what will happen within a few years? Maybe such buildings will become common solutions …
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