a flap for air to rise through? good idea
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Will make it closable for when guests turn up. And yes its a 135 watt cfl, i'll keep checking it to see if temp builds up to much and its 6 hours off will be when im in bed, one person is generally in, so it wont go unattended. I agree it would be better without the box but it would be less stealthy. I'll keep an eye on it. thx mike4c4 for the advice.
EDIT:- Smoke alarm about 2 metres from box and working.