Stumbled on a very kewl web site called degreedays.net – it allows you to pull up a spreadsheet of heating degree days for locations all over the world. I was able to quickly generate a spreadsheet for a weather station not too far from my house – and use it to calculate the heating degree days in a specific time frame.
I’ve been keeping track of how much oil we use to heat the house – but it’s pretty difficult to use that information to predict things because of the constantly changing temperature. For example: I had calculated gal/day based on the data I had – and realized that this number is going to fluctuate wildly throughout the year and it isn’t a really useful number because it doesn’t take into account the outside temperature.
Enter heating degree days (HDD) – which allow me to calculate how many gallons of oil I use based on the outside temperature. There’s a very good explanation of HDD on this website.
I’ve only had 3 oil deliveries, so I only have 2 periods to measure. Right now I’m averaging 0.14 Gallons of Heating oil Per Heating Degree Day.
The real goal is to know that 0.14 number today, and work on lowering it for tomorrow.
2010-03-04 Updates: Been tracking for over 1.5 years and my average is still 0.14. Haven’t made any improvements to the house that should have lowered the number. It’s pretty consistent around 0.14 with the exception of early January this year.