with the assistance of my striker C160( a very small insert ) I used 73.2 gallons in my two story 1875 square foot home with 4 people living in it( delivery date 01-29 house located in Long Island NY). The average temperture being maintained on 20 to 25 degree nights being 69 degrees. Using my oil burner to generate hot water for showers. The bad news that 73.2 gallons cost me 3.749 a gallon for a total of 281.29. OUCH