The residential sector is responsible for approximately 40% of final energy consumption in the European Union, being a potential target to increase energy efficiency and improve urban air quality. New high-efficiency heating oil boilers have been developed requiring fuel adaption by diminishing the sulfur content in the fuel. The present work has led to the conclusion that further fuel development, including the use of alternative fuels, may be directed to reduce fossil fuel consumption and decrease the formation of pollutants. Specific fuel properties, such as distillation curve and nitrogen content, show an influence on pollutant emissions, especially NOx, which can be reduced below the lowest limit required for gas domestic boilers, which, until now, set the state of the art in terms of NOx emissions. The addition of renewable fuels in heating oil formulations, contributing to a global CO2 decrease, does not affect the reduction in NOx emissions as far as it does not affect the nitrogen content and distillation curve of the fuel. Besides, a map of NOx emissions, useful to predict NOx emissions from the latest generation heating oil boilers, independent upon the type of fuel, has been inferred, and an equation has been proposed to guarantee low NOx emissions depending upon fuel properties.