Example – Lindås, Sweden
In 1970 the energy need in Swdish dwellings was 310 kWh/m2 floor area per year. In the mid-1990ies, this was reduced to only 160. Nowadays superinsulated low energy dwellings are being put up. One of the first ones in Lindås by Gothenburg, designed by Efem Architects. The project includes 20 row house units, each of 124 m2. Normally each such units would need 21.000 kWh per year.
The Norwegian State Housing bank have expressed that there will be a considerable market penetration if housing units that had a total energy need of 80-90 kWh/m2/year, could be produced in large volumes. Goal number one when designing such dwellings is to reduce heat losses in the winter and cooling need in the summer. This is achieved in Lindås through generous insulation in walls, roofs and floors. Insulation against wind, well insulated windows and doors with specially well insulated frames, is a condition to reducing the energy need. Thereafter, solar thermal is used to cover part of the DHW heating (5m2 solar absorber/500 litres water tank) and a balanced ventilation system (0,5 air changes per hour) with 85% heat recovery, reduced the dwelling unit´s total energy need to 1/4 of traditional need. Energy efficient domestic household appliances were also selected as part of the project. U-values :
Dwellings based on this standard will make use of the body heat from its inhabitants, contributing with 1200 kWh/year. Heat from lighting, refrigerators, freezers and other technical equipment contributes with 2.900 kWh/year. The result is : The need for a traditional heat and heat distribution system is eliminated ! Only a 1 kW movable small heater (electric or oil,gas or bio) is necessary in short extrem cold spells. Traditionally the need in most dwellings in Scandinavia is an installed effect of 10 –20 kW. One huge gain of such an approach if widespread is that the load on the national energy system is reduced. The additional costs for extra insulation and other fixed installations amounts to EUR 5.000 – 6.500. The solar heating system EUR 2.500. (Additional costs for the energy efficient houisehold appliances amounted to EUR 1.500, but today the extra costs for such choices are negligeable.)
In Sweden at current energy prices, this will lead to reductions in energy bills of EUR 1.300 per year (21.000 kWh – 6.000 kWh = 15.000 kWh saved x EUR 0.9 / kWh = EUR 1.300 per year). The additional costs are hence paid back as a result of reduced energy bills within two years. For more information go to internet : www.enova.no/?pageid=2035 ”We build for 2050 – not for today only”.
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