In a renovation situation of existing windows there is a large potential to improve the energy efficiency of the whole building by replacing one of the clear panes to a low-e pane. We have in this paper shown by using the simulation tools ParaSol and Rayfront that some improvements are made by using an AR-coating together with a low-e coating. By adding an AR low-e pane compared to only using a low-e pane, the heating demand decreases with 1-2%. This could be related to the higher solar transmittance that increased with 2%. Using a low-e coating increased the indoor temperatures and the risk of overheating but using the AR-coating in combination did not increase the temperature more than the low-e coating itself. The real benefit of using AR-coating in combination of low-e coating is the improvement of the light transmittance and the daylight factor. The Rayfront simulations showed that the daylight factor increased by 12% compared to the low-e DG. The daylight factor with the AR low-e coated window actually reached the same level or higher as for the standard clear double-glazed window. The conclusion of this paper is that the AR-coating can be justified from the daylight perspective, but not from the somewhat lower energy demand that it brings.