To raise the share of renewable energies in the domestic heating market, the use of bio heating oil becomes increasingly important and popular. Considering the German heating market, bio heating oil blended with 10% biodiesel is already available. The affinity of biodiesel to forming oxidation products requires fast and reliable measuring methods which cannot be covered with conventional methods such as the Rancimat method according to DIN EN 15751. Therefore, a new measuring technique is introduced in this work, where oxidation products from heating oil blended with 10% biodiesel (HO B10) and for comparative purposes neat heating oil (HO B0) were investigated by dielectric spectroscopy. The results were verified by gel permeation chromatography (GPC) and by measuring of the total acid number (TAN). The alteration of dielectric parameters during the accelerated aging is used to determine the oxidation stability. (C) 2014 Elsevier Ltd. All rights reserved.