I was worried about that myself so made this mainly as a proof of concept. I had some plans to add small fans and heat sinks if they were needed.
In a real world setting its used as an accent light rather than being on full power so the heat really isn't a factor at all. I tend to set it to a warm glow where the fillement isn't to bright to avoid hurting the eyes.
I did think about using a glass tube instead of the bell jar with would give a similar look to the old gas lamps/ live flame lamps but after using this lamp during the winter I don't think there is much need to replace one glass for another, and aesthetically i like the half capsule.
Though the glass gets warm to the touch it is a comfortable warmth (certainly less warm than my laptop gets whilst I use it on my knee), but to be fair I wouldn't recommend someone touching this part of any lamp whilst in use.
The one problem I do have I think could be fixed with slightly better electronics. I am using an inline dimmer and though very quiet it does make a noise in use. I think the next one I make will have i touch operated dimmer, will not have the bell jar and will be made from maple and black walnut. (possibly with a brass ascent)
