Balanced ·mechanical ventilation with heat recovery (MYHR) offers, in principle, a way of reducing carbon dioxide emissions from dwellings. In order for such systems to produce a clear reduction in C02 it is necessary for the emissions from the low temperature heat saved to exceed those from the electricity used to drive them. This condition places a lower limit on the coefficient of performance (COP) of MYHR systems, which in the UK is around 3. The major variable in system performance is the electrical input to the fans.
Commission, the UN commission for development and the environment, has recommended a great effort on more efficient energy use, so drastic that the industrial countries would half their use of energy. Already today, it is possible to reduce the energy use in buildings with the help of known and economical technology. The technical committee ISO/TC 163, Thermal insulation, of the International Organization for Standardization, ISO, has produced some of the tools we need in order to determine the energy flows in buildings.
The energy efficiency of multi residential buildings in Canada has not kept pace with energy efficiency improvements in other commercial building sectors. Energy efficiency is subordinated to a dedication to reduce first cost of buildings in this sector. Lower first cost and energy efficiency are not mutually exclusive, however, building designers will have to learn to work together to achieve optimum results. The current practice and energy use of new buildings are reviewed in this paper.
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