Red brick may be absorbing more heat from sun; therefore
record a warmer temperature. Sunbathing adjacent to a sunny
brick wall on a cloud and windless winter day can be warmer
for same reasons.

What I am getting at is to question what it is measuring.
Three types of heat transfer exist - conduction, convention,
and radiated. Is this only measuring radiated heat, and does
measuring by this method provide an honest estimate of all
heat lost? For example, are there locations where hands feel
warmth but the meter declares a lower or same temperature?

"P. Thompson" wrote:
It is pretty sensitive.

Part of my house is a stone foundation and part is brick. It surprised me
by showing that the (thicker) stone foundation insulated better than the
brick by being 49 degrees (inside the basement) in general rather than 44
for the brick. I guess it makes sense in retrospect.