I have a boxed NZXT case with a corsair power supply installed inside it in its box and a motherboard in it's box on top of that. I have a small 58w fan heater 4ft away, but the stream was accidently faced toward the boxes for about 15/20 minutes. There won't be any damage will there? It's just a heat element inside it and the air blows out the heat. See picture
