I’m curious if anyone see a difference between batt insulation and icynene insulation when installed in the wall cavity at the floor and ceiling. Normally I see a thin brighter image along the baseboard/floor and at the wall/ceiling point with it hot outside and cool inside with batt insulation. Wondering if anyone seeing the same thing when icynene is used or does it seal better.
I would say that you would see less insulation voids with the spray insulation, but you would not be able to tell the difference between batt and foam with a thermal image if the batt was installed correctly. The ceiling corners may always look warmer with a hot attic and a wood top plate (thermal bridging).
Basically the amount of infrared radiations emitted from the surface is depends on the emissivity of the surface. Accurate evaluation of the surface is required to obtain meaningful quantitative results.
There was no mention of quantitative analysis in the original post. The surface material in both instances is almost always painted sheetrock. Compensating for emissivity differences is a non-factor in this comparison of thermal patterns.
The thermal patterns often observed at top and bottom plates are typically due to several factors: 1) the wood plate has a lower R value than the insulation so it conducts more heat than the insulation;
2) plates are typically poorly sealed and admit a decent amount of air leakage under/over them and through penetrations in them;
3) fiberglass batt insulation is often not perfectly fitted at the plates and allows heat transfer at the gaps.
Changing to foam insulation, I would expect the following differences when comparing the above factors:1) the disparity in R value between the insulation and wood plate will increase, exaggerating the portion of the effect due to conduction;
2) air leakage at the plate itself would be unchanged, however IMO, foam insulated assemblies are usually coupled with somewhat greater care for the thermal envelope overall, so I would typically expect to see better sealing of the plates. The foam itself will provide an air barrier at the penetrations. So this effect would be reduced.
3) foam creates a more positive fill at transitions, corners, etc. typically with no gaps. Coupled with the foam being an air barrier I would expect this effect to be reduced.
In my personal experience, I typically see less of the sharp thermal contrast typical of conventional fiberglass batt filled assemblies when the wall is foam insulated.