This will be the 4th time I think I've said don't burn your window curtains and burn down your house with an incense smoke test. I have done told you.

Cheap method to find air leaks from windows. You may not think about it but your home is a system based on systems. If the windows leak, that is money going out the window. If the house is pressurized the smoke comes goes out. If the house is under a negative pressure that the smoke goes in.

I have lots of videos showing you many ways to test your house.