New VTT technology reduces consumption of heating energy to a third

Led by VTT, a housing building technology has been developed by which a home in an apartment block can actually be heated with 70 per cent less energy that at present. The first apartment block home to be built with low-energy technology was taken into use in Leppävaara, Espoo this summer. The objective is to employ the same technology in the building of a whole block of such homes next summer.

Juhani Laine, Senior Research Scientist at VTT (left) and Erkki Tolkkinen, Chairman of the Board of the firm Rakennusliike Reponen Oy are well informed on low-energy housing building. In the background is a block of flats in Leppävaara, Espoo, where one of the apartments stays warm all year with no radiators. High resolution image (972 Kt) Photo: VTT

The additional 2-3 percent costs of low-energy building are rapidly recovered in long-term heating energy savings. The 10-year saving in one low-energy apartment block is 50,000 Euros compared to a block built according to the present requirements, since the cost of energy is rising at a rate of 3-6 per cent a year. In 50 years at the same rate the saving to the low-energy apartment block would amount to 400,000 – 1,000,000 Euros. The low-energy building will make it into the best energy class next year when European energy performance certificates for buildings are to be introduced.

From the perspective of the national economy lifespan economic low-energy building would make great sense. If new residential buildings were built using the method developed, the saving by 2030 would correspond to the district heating energy consumption of the entire city of Helsinki (the current annual consumption of the city of Helsinki for district heating is 7.2 TWh ). For companies such as SATO and VVO, which have thousands of homes built every year, low-energy building would be a most profitable investment within 10 years.

The low-energy apartment built at Espoo utilises the heat generated in living: the heat generated by people and household appliances. This is recovered with the new ventilation-heat recovery system. Thus the need for extra energy from outside the home needed for heating is only for only 2-3 months, which is produced with the same ventilation heating system. Moreover the cooling of the apartment in summer is achieved through the combined result of structural solutions and ventilation.

In the low-energy home constructed the kitchen and bathrooms are located so as to avoid heat loss through conventionally lengthy pipes, while the sauna was constructed so the size can be changed according to need and is easy to repair. During building great care was also taken of the tightness of building elements, windows and doors and to avoid cold bridges, thus energy savings are the result of many details.

The low-energy home was developed by VTT, Mikkeli Polytechnic, the Rakennusliike Reponen Oy, Meptek Oy, Skaala Windows and Doors and Salon Sauna Oy. The project also reseived funding from Tekes.

Further information: