Economic Evaluation of Net-Zero Energy Houses

This study analyzed and evaluated the energy performance and cost using electricity data from KEPCO (Korean Electric Power Corporation) and actual PV generate data. The analysis was conducted in two houses with different location and size. The demonstration houses were constructed with high thermal insulation and air tightness, and also designed as all-electric houses where all the energy supplies (including heating and cooking) are made of electricity which reduces the maintenance cost and makes maintenance easier. 6kWp grid connected photovoltaic system and air source heat pump for heating and hot water were applied to both houses. The result is summarized as follows. First, for two years, all energy (including plug load, heating, cooling, lighting, hot water supply and ventilation) was supplied by PV system and consequentially zero energy was achieved in both houses. Second, as a result of load matching analysis, in both houses, LCF in summer was relatively higher than that in other seasons and SCF in winter was relatively higher than that in other seasons. Third, monthly electricity bill by the amount of used were not charged, however, additional fees by domestic electricity charging system were charged such as basic electricity fee, VAT on receiving electricity and development fund; average $115 were paid per household.