Weather data#
It matters what the weather conditions were like outside when you took your temperature readings. The gold standard is to put a waterproof monitor outside, but a good “second best” approach is to check the historical weather record at the closest weather station you can find. You might find this useful for thinking about your temperature data.
Up for more formal analysis?
Engineers and people who like spreadsheets may wish to plot internal against hourly external temperature. They use weather data more like this.
For the adventurous, there is a useful website for understanding and calculating degree days so that you know much heating or cooling was needed over a given period.