Nosferatu said:
I would say smoking is better if you have full out insomnia but with high temps and a waterpipe I think the vape can get you just as sleepy, it certainly gets you more lazy.
+1
Vaping at higher temps is the key to unlocking a more sleep inducing hit.
Another factor is how good your vape is at get a thick milky hit. Some like the SSV are much better at it than others.
Connecting your vape to a bong, bubbler, or other inline cooling device is also helpful, as it will let you take a bigger hit at higher temps without causing your lungs to spasm.
When I really want to get to sleep, I'll mix some strong indica flower with some indica hash or oil and then vape/bong that at around 220-230c.
For me vape bonging at higher temps is a more effective sleep aid than bong hits.