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Energirenovering af typisk parcelhus opført i perioden 1960-1980, Del 2: Målinger

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The report presents results and compares energy and indoor climate measurements before and after an extensive energy renovation of a typical Danish single-family house from the 1960/70s. The measurements before the renovation started at the end of June 2005. As the renovation was held up (started September 2006) measurements for a whole year before the renovation is available, i.e. September 2005 – August 2006. The renovation was completed December 2006 and the measurements therefore only include the period from January and February 2007. The measured energy consumptions for room heating before and after the renovation have been scaled up to yearly energy consumptions and converted to standard conditions regarding indoor and outdoor climate, i.e. 20°C indoor temperature and standard weather data corresponding to Danish Design Reference Year (DRY). Implementing these corrections, the yearly gross energy consumption for heating before and after are 35 MWh and 12 MWh respectively. Accordingly, the energy savings amount to a whole 23 MWh or a 65 % reduction. The air change rates were measured both before and after the renovation and using both PFT and CO2 methods. In the before-situation air change rates of 0.3 to 0.4 h-1 were measured. After the renovation a standard adjustment of the air flows in the mechanical ventilation system was carried out showing 0.45 h-1. Subsequently, the PFT method nearly confirmed the air change rate (0.51 h-1) when considering the increase by the air infiltration. The air tightness measured using the “blower door test” resulted in air change rates before and after the renovation of 8.5 and 1.4 l/s/m2 respectively. This constitutes a great improvement in the air tightness to a level of the requirement for new houses in the building regulations (1.5 l/s/m2). The measured indoor temperature level was approximately 2°C higher after the renovation (21.9°C compared to 20.1°C), which is based on measurements in the same time of the year (month of January and February). Generally, the energy renovation has greatly improved the thermal comfort but the higher temperature has its drawbacks as it results in higher energy consumption compared to a situation where the temperature was the same as before the renovation. The relative humidity level is reasonable and generally a little higher after the renovation (35-40 %) compared to before the renovation (30-35 %). One should expect a reduction because of the higher temperature level and a little higher air flow rate. However, comparing the two situations on the basis of the existing data is problematic as the inner and outer moisture conditions have been different.