This is our 2nd Season Heating with a Propane Furnace... I Misplaced the Formula to calculate daily consumption so we can watch the Cost to Heat.. We have 2 / 465 litre tanks for a total of 930 litre's , but due to Delivery regulations the Tanks can only be filled to 80% capacity or 744 litre's.. From this point I'm drawing a Blank, From the Date on the Delivery Ticket counting X number of days and the reading on the Dials on top of tanks..? Help Appreciated , Cheers Thanks..

Tanks read % full so at 60% you have a total of about 446 liters. 1 gallon of propane is 91,500 BTU, 1 liter about 25,000 BTU. I am using gallons since my tank is that way. So first, determine your BTU consumption per hour by using the heater plate. You also need to factor in the AFUE-% efficiency You can then determine hourly gallonage when heater is running full and this is on an hourly basis. So, with a 60,000 BTU heater at 80% means a consumption of about about 72,000 BTU per hour for what equals 100%. It really doesn't but that is one way to calculate. So, 72,000/91,500 tells you roughly how many gallons per hour. Now realize heaters don't typically run 60 minutes so you need to determine the actual % running time. You can then do liters to gallon conversion.