Friday, December 2, 2011

Now I'm in the mood

For doing calculations, as I have to ascertain whether all the effort was worth it or not.
So, I have this curve fitting against which I can compare my gas consumption based on the average outside temperature for the month. But his is done for a month, and I wanted to see if I could go to a lower level, so I found in the KNMI website a service from which you can download all kinds of meteo data for a time period.
I downloaded the average month temperatures for "De Bilt" as that is where I have been basing my calculations all these years, although not the closest station, and plotted it against the daily gas consumption. I couldn't go away without putting it here, so here goes, for the month of November:


Henk said...

If you plot 'graaddagen' against gas usage, you have even better information,


Alex said...


I didn't know about these "graddagen"! interesting concept, and indeed it appears to be used by many to do what I have been doing.

The formula would be something like:

GD = ∑max[0, (18-T)]

In fact what it does is just to invert the temperature curve in the graphic I posted (saturating the temperature at 18C) and making it very easy to relate. Especially if you tweak the "18" such that the graaddag value almost equals the gas consumption! I might put a graph of that later tonight!

Thanks for pointing it out!