You'll have to be cautious of temperature, humidity, ventilation. It will be easier to heat/overheat, same with humidity. If you get it too humid with limited ventilation they can develop respiratory infections.
I also live in a cool climate area and I would not keep a veiled in one personally. I would keep certain species of montane chameleons in there, but with little to no basking bulbs and maybe a fan on low to pull fresh air through.
Screen cages work better for veileds in most instances, but if you were keeping the enclosure in an unheated garage, the glass vivarium could be exactly what you need to keep your cham warm enough.