The Beast Slayer
First of all: ditch the aluminium foil!!!!
You can switch it out for white paint or a rescue blanket, both have WAY better reflection.
Rescue blankets are focused on reflecting and containing infrared light (heat). They may cause your space to heat up by containing and reflecting the heat.
I have a friend who had some rescue blankets up that he took down.
That day his temps in a 10'X10' space with 2 1,000 watt lights dropped a couple degrees.
Just something to think about.
I personally would rather use some flat white paint with high reflectivity (if I needed to line a surface)