Energy and cost analysis of household electricity efficiency improvements in a rental apartment building

Abstract: In this thesis potential for (final and primary) energy and CO2 emission reductions and cost effectiveness of replacing existing household electric appliances and light bulbs with most popular or most energy efficient appliances in a multifamily apartment building in Växjö city is studied. The results showed that there is significant potential to reduce electricity demand and thereby to reduce primary energy use and CO2 emissions. The greatest potential lies with replacing existing incandescent bulbs with LED bulbs, while the lowest savings seem to be with replacement of microwave ovens. Assuming that reduced electricity demand reduces electricity generation in coal-based steam turbine (CST) technology, annually about 63 MWh of primary energy and 25 ton CO2 emissions could be reduced from the investigated building if the existing refrigerator/freezer, stove/oven, microwave oven, televisions and light bulbs are replaced with the most energy efficient alternatives available in the market today. Also, the results from ‚discounted payback period‛ and ‚cost of conserved energy‛ analyses also showed that it is cost-effective to install the most energy efficient appliances. This study for a single building is based on limited number of interviews, selected appliance types, and number of assumptions about marginal electricity production systems. To generalize the results more such studies in different conditions with measurement of actual energy use of all the household appliances should be conducted, which would help to fully understand the potential of primary energy savings and CO2 emission reductions in Swedish apartment buildings.