You can feel the difference with oil heat. There are many technological reasons that contribute to the legendary warmth of oil heat. A high percentage of oil-heated systems are hydronic rather than warm air. Hydronic systems provide a more steady heat. Oilheat systems are sized to provide very fast recovery times for both space and water heating. Oil heat systems suffer very low infiltration losses; that is they draw relatively little air out of the building that must be replaced by cold outside air.