It has been a lot warmer this week, which is nice, but not so great for doing comparison testing. While my house stayed within half a degree (17.4°C instead of 17°C) the outside air temperature was 8.5°C warmer (8.3°C compared to -0.1°C) over the test period (20/01/2024 to 24/04/2024).
But no matter, I still run the tests with just an air void and the void filled with a product called Fillite, which is hollow microspheres made from silica.
Basically the same pattern was observed with the two samples performing in a similar manner. The temperature differences, within the samples, are different with the air void showing a mean ∆T of 1.1°C and the Fillite at 0.7°C.
The slope of the trendlines was less, but not significantly so.
The slope of the Air line is 0.1, which means that for every 1°C change in the temperature difference in the overall temperature, the sample only changed by 0.1°C
The Fillite was 0.15, so better.
The Clingfilm slope was 0.14, so almost as good as the Fillite.
The Aluminium Foil was 0.2, so the best and twice as good as just an air gap.
So there we have it, possibly. A bit of tin foil creates a greater temperature difference over the temperatures samples, even of the overall temperature differences do not see so different.
A small change, of a small amount, equates to a very small change.