Thermal survey or use an infrared (IR) camera? - what's the best way to see how to improve insulation and reduce heat loss?

One advantage of this cold weather is that I can see how useless my double glazing is, and how useful even a thin curtain is. This is in my unheated loo !!

You need to be very careful when taking thermal readings from glass, mirrors, metal or shiny surfaces. The emissivity of different surface types varies considerably. With really shiny materials you can be viewing the reflected heat from the room or yourself rather than the actual heat of the surface.

For example, here's a thermal image I captured to illustrate the point. This is my reflection in the glass of the patio door from inside the dining room. The glass isn't a whole variety of temperatures that, spookily, exactly match me. The glass is reflecting the room temperature of walls and furniture and me within it.

You can see part of a wooden chair that's at 20.2C, but the glass? Not so sure.

It will work well with walls, floors, ceilings, paint, brick etc. Glass, not so much.

Yes @eezytiger I’ve used foil wrapped insulation over my foam lagged pipework, knowing it’s not going to show a true reading (being shiny)  I’ve been wondering whether to drape a cloth over it to test for heat leaks. Would that make sense or just skew the reading?

Note to self - must find out how to focus the Seek !

Ideally you want something that makes close contact and isn't itself a reflector or insulator. A cloth wouldn't transfer heat well from the pipe through to the outside of the cloth, or not quickly. I mean, we wear clothes made from cloth in order to keep warm. :-)

A good tip is to stick bit of (matt if possible) electrical tape to the pipe, glass etc. That way, no fluffy air gaps.