Seven Rules For The Design Of A Low-Energy House
What are the key factors when planning a low-energy house? The following seven rules are intended to provide an overview and a guide.
1. Work according to a concept
The form, location, and interior layout of a building have a major influence on the energy consumption. Strive for clear, simple solutions. If you are not inventive by nature, assemble your house (intelligently) from inexpensive, readily available parts.
2. Plan a high degree of insulationâŚ
The thermal insulation of a low-energy house is at least 20 cm thick. Depending on the type of construction, the complete external component can be between 25 and 60 cm thick in total.
⌠and avoid thermal bridges The problem of thermal bridges occurs wherever the insulated building envelope is penetrated by components which allow the passage of heat from inside the building. Many buildings lose more heat via avoidable thermal brid- ges than over the entire uninterrupted wall. Transitions and junctions require special care: â between window and wall, roof and other windows, â between door and wall, â between wall and roof, â between roller shutter and wall, â via shafts and flues at wall and roof, â via thresholds, window sills, lintels at floor and wall, â via fasteners, e.g. for balconies.
3. Exploit solar heat gains Include large windows on the side facing the sun, provided their energy audit is positive. Adequate storage capacity is necessary in order to absorb the radiation. This means that a heavyweight form of construction is preferable for internal partitions and floors. Position permanently habitable rooms, e.g. living room, childrenâs rooms, on the sunny side whenever possible.
4. Build airtight⌠No house without convection safeguards! The occupants breathe, not the walls, nor the roof. Ensure airtightness and check the workmanship, particularly at troublesome details.
⌠and install mechanical ventilation This will increase the quality of life in the house and reduce energy consumption because the heat losses can be recovered (heat exchanger). The ventilation plant must be carefully sized, and disturbing noise can be reduced with sound attenuation.
5. Cover the residual heating requirements with renewable energy media Solar energy, wood, and ambient heat are ideal for low- energy houses because small installations (heat pumps, collectors) are adequate for low energy requirements, or only a small amount of fuel (wood) is necessary.
6. Store and distribute the heat with a low temperature level⌠The lower the temperatures of the heating media, the smaller the losses; this applies to both the generation and the distribution of heat.
⌠install the heat storage media in the heated part of the house⌠Every storage medium loses heat; this heat must be used in a low-energy house.
⌠and insist on short lines In some low-energy houses the supply and return pipes (due to their large surface area) heat up more than the radiators being supplied. This can lead to problems in the regulation of the heating system and to unnecessary energy losses.
7. Use energy-saving household appliances The use of energy-saving household appliances reduces emissions and environmental loads at the power station locations.
Excerpt from:
Othmar Humm: NiedrigEnergie- und PassivHäuser, Staufen bei Freiburg, 1998
