Propane Usage 2000 Gallons over 1 year period. At the current pricing for propane, we find this to be a very high cost for heating and cooling. I am afraid of spending 500+ per month for this, let alone $750. It will be just the 2 of us moving into the home.ropane Usage 2000 Gallons over 1 year period. At the current pricing for propane, we find this to be a very high cost for heating and cooling. I am afraid of spending 500+ per month for this, let alone $750. It will be just the 2 of us moving into the home.