Monthly Archives: August 2019

It’s Getting Warmer – Morning Data Points

In my previous post I described how I got data from my weather station into MATLAB to help me answer my primary questions:

  • When to open the windows in the evening, to let in cool air?
  • When to close the windows again in the morning?

The data I have available covers 10 days, including a late July heat wave. At first I tried to understand when the lowest outside temperature was reached and when it increased again by more than 0.5 °C and 1 °C compared to the minimum.

DayMin Temperature (°C)TimeTime +0.5°C Time +1°C
18 Jul 201916.305:54 06:5406:54
19 Jul 201917.005:56 06:5207:12
20 Jul 201920.405.56 07:0108:07
21 Jul 201920.705:45 07:0007:56
22 Jul 201919.905:56 06:2707:22
23 Jul 201920.406:14 07:0508:21
24 Jul 201921.405:53 06:4807:33
25 Jul 201922.106:16 06:5107:17
26 Jul 201922.905:42 06:1707:13
27 Jul 201923.105:50 06:3607:36

If I had more data I’d plot a histogram of the times to decide when to close the window in the morning. For now, I can only come up with a “manual estimate” based on looking at the table above. I conclude: During summer I should close the window by 7:30 in order to optimally protect the cool indoor climate.