AbstractWith increasing population and increasing demands for comfort and thus an increase in energy demand, it is necessary to examine various energy-efficiency measures. This work deals with the ability to control the flow through the heating system to achieve the desired comfort with as little energy as possibleA heating system contains of different parts, roughly speaking, you can divide it to three main components: Heat source, Distribution and Heat emitters. All components are working together to bring heat to the building. What is examined in this report are different ways of adjusting the flow and supply temperature and how it affects comfort and energy use in a building.At today ́s date the conventional method is to use a high flow through the heating system, which affects pressure drop and cooling of the fluid. In the mid 1960 ́s there was an engineer named Östen Sandberg that started to use a lower flow rate with a higher supply temperature as a result. The upside of that was that you could neglect the pressure drop that the fluid in motion contributed with and that it helped to reach the desired comfort.The purpose of this study was to determine if a low flow adjustment is a viable option and to see its advantages or disadvantages.The author of this work has made use of the software IDA ICE 4.0, which is a simulation tool for indoor climate and energy usage, to a build a residential building and then applies different scenarios such as extreme thermal bridges and internal heat. After that used different supply temperature to simulate a low/high flow.A general conclusion of the work when using a simulation of this kind is that a low flow with high supply temperature is better to adapt to different circumstances and is able to keep the desired temperature at the expense of a negligible increase of energy. The adjustment of heating system seems to be an easier task at low flow than at high flow because of the dynamic pressure drop that occurs with fluids in motion becomes negligible.