How to watch heating oil prices

We have a little secret at our place for determining the timing of the purchase of our furnace oil.

This website allows us to look at trend data:

http://www.fuelfocus.nrcan.gc.ca/prices_bycity_e.cfm?PriceYear=0&ProductID=7&LocationID=66,39&dummy=#PriceGraph

We also have designed a spreadsheet to track how many litres we have in our tank and how much we use, per day, on a seasonal basis. This tells us how much reserve we have and based on the tank size, we can tell how long our tank will last. That gives us the opportunity to wait for lower prices, assuming the trends are there.

By doing so, we can buy less oil during the peak season (stretch each tank out longer) and wait to purchase fuel during the non-peak seasons when it is cheaper (i.e. summer, late summer).