[zdragnar]

If there is a thermal difference (cold outside and furnace is running, or hot and AC is running) a cheap thermal camera can find them fairly quickly.

In the US at least, where building codes favor air sealed construction, door blower tests are fairly accessible: https://www.energy.gov/energysaver/blower-door-tests

[kolinko]

How did you use the thermal camera exactly? Any tutorials on that?

I have a garage, and I had issues with using the thermal camera - if the building materials were not uniform they reflected/radiated IR unevenly. It could show a piece of uninsulated area as hot and very well insulated as cold.

[namibj]

Get some wash-off spray-on chalk (essentially spraypaint that won't survive the next rain, because it's made to disappear when hit with rain/a hose). That should give you sufficiently uniform surface emmissivity to deal with those problem spots.

[kolinko]

Thanks!

Do I do the measurements from the outside then, not the inside? Seems difficult in some cases unless I have a drone (roof, other hard to reach areas).

Do you know if i can find a tutorial anywhere? I tried googling, but couldn't find anything easy to understand.