Thermal imaging camera query

ebc

We have borrowed a FLIR B50 Thermal Imaging camera to try to find out where our house is losing heat.

Does anyone have any advice on a methodology for using the camera and getting useful info from it which could help us decide which are the most cost-effective changes to make.

 eg Is there any formula/rule that helps you work out whether a cold spot it identifies in a ceiling would be cost-effective to fix with extra insulation ?We have a chalet with dormers and looking at the bedroom ceilings from inside the room it has identified cold spots on each of the dormers relative to the adjacent ceiling which has loft space above it. However, the dormers are difficult to access and I’m wary of trying to add insulation there after seeing warnings about vapour barriers and damp. What sort of temperature difference would be big enough to make it a decent return-on-investment to fix the problem.

 Or should we be looking at the outside temperatures of the house eg wall vs window vs loft. Again, what sort of difference in temperature would identify something worth fixing.

 Having borrowed the camera we’re not quite sure how to interpret the information it’s giving us 

matelodave

Is this any good - scroll down a bit and it shows what you are looking at and how to interpret what you are seeing - https://octopus.energy/blog/flir-thermal-cameras/

Miser1964

Numerous YouTube videos cover this too