Got another chance to do a cooldown. This time I had more time, but started with a lower temperature. Here's the data:
| Hour | Time | Indoor temp | Outdoor temp |
| 0 | 9:00pm | 19 | 8.2 |
| 8.75 | 5:45am | 18.25 | 6.4 |
| 10.75 | 7:45am | 18 | 6.8 |
| 11 | 8:00am | 18.25 | 6.5 |
| 12.75 | 9:45am | 18 | 7.7 |
| 18.25 | 3:15pm | 17.75 | 8.7 |
| 24.75 | 9:45pm | 17.5 | 7.6 |
| 32.5 | 5:30am | 17 | 7.3 |
This test took over 32 hours, and the house cooled only 2 degrees, from 19*C to 17*C, while the outdoor weather was identical to the previous test. This shows that cooldown testing must be repeated a lot of times and averaged.
BTW: The raise in temperature at hour 11 is after the TV was on for 30 minutes.