I can’t say whether or not heat wraps promote better gains, but it sure helps my dick stretch easier and longer. There are several ways to warm up that don’t eat into your time so much.
As stated above you can warm up in the shower. I do this in the morning. Before I get out I run the hot water from the spigot over my dick and do stretches. Then when I get out I’m plenty loosened up to do jelqs.
I also do heat wraps and light stretching while watching tv, reading, or using the computer, (I have one on right now). A good wrap for this is the microwavable gel packs you can get in the drug store. It takes a couple minutes to warm up and then its ready to wrap around your meat. They stay warm for quite awhile.
I also wear a heat wrap all night while sleeping. I sleep with a traction wrap and then place the gel pack around that. I think this should promote faster healing while in a stretched form. I usually have good sized erections in the morning after that.