The thermal time constant of a building is around a day, so you should really be running each of these tests for more than a day (and correcting for differences in ambient conditions). Basically, the control should exceed the average ambient temp because of solar and internal (e.g. electricity consumption) gains. And see my other comment about doing something about humidity removal. Then we might actually have something rigorous (based on doing an experiment with fairly expensive equipment, I still had error bars around +/-1°C, so I don’t think you have very much confidence at this point).
The thermal time constant of a building is around a day, so you should really be running each of these tests for more than a day (and correcting for differences in ambient conditions). Basically, the control should exceed the average ambient temp because of solar and internal (e.g. electricity consumption) gains. And see my other comment about doing something about humidity removal. Then we might actually have something rigorous (based on doing an experiment with fairly expensive equipment, I still had error bars around +/-1°C, so I don’t think you have very much confidence at this point).