Affordable, simple IR (if it ever materializes...)

Any auditor or insulation tech knows how useful an infra red camera is when insulating sidewalls.  There are some really fancy (read: expensive) models and other cameras that are more affordable, but have fewer bells & whistles.  Here is a crowd sourced option that looks like it might fit into a Wx toolkit rather nicely.

Mu Thermal Camera

All you need is a spare iPhone, and the hope that the campaign to build it is successful.  If you're feeling optimistic, there are still some slots open to buy one for $150 (plus S&H).