Indoor Best light bulbs for heating growbox?

[Basiltherat]

I've a v chilly box that I built, insulated but sitting at 11c with the 150w led ufo on.... I've a heat mat, and was considering a tube heater. Would it be cheaper and easier to use a few lightbulbs instead? If so what sort? I've not got room for a mini oil filled rad and don't fancy using a mini blow heater....

Cheers!

 

[AutoWonders]

I have my radiator heater in a two drawer file cabinet that is pushed up to one of my lower screen vents. The inline fan sucks in the warm and toasties.