The study deals with low-energy District Heating (DH) networks operating in low temperatures such as 55 degrees C in terms of supply and 25 degrees C in terms of return. The network layout, additional booster pumps, and different substation types such as storage tanks either equipped or not equipped in domestic hot water production site were examined. Effects of booster pumps on pipe dimensions in the latter case were investigated. Temperature drops during the summer months due to low heat demands of consumers were explored. Use of approaches such as looped networks and branched network layouts with bypasses for end-consumers were also studied, heat loss from these networks and the drop in temperature in the heat-carrier-supply medium being compared. (C) 2012 Elsevier Ltd. All rights reserved.