It all depends on the H. You never know what its going to be like until you actually test it out, which by testing I mean taking a very small bump just to see what your working with. I think heroin is a more sedating than oxy is IME with them both. Oxy is different, it starts out sedating and is very euphoric to me after I sniff a 30mg IR, then gets kind of somewhere between sedating and stimulating. It usually lasts about 3 hours more or less depending on my tolerance at the time... Heroin has been very different from one batch to another when I used to do it. Sometimes I would be lit for like 6-8 hours from sniffing like a 0.1 of H, sometimes I could do 3x as much as that and not even be nearly as high as I was with the 0.1 of some real good shit, and it wouldn't last as long. I didn't sniff it very long before switching to IV for the rush and more efficient BA(Big mistake, wish I never tried it that way). It will vary a lot from one bag to the next.. Very hit or miss these days, with the whole fentanyl laced heroin epidemic going on... Be careful. Start small and go from there.