Among its disadvantages we can note poor impact resistance and low chemical resistance, especially to solvents. Polystyrene does not tolerate strong acids and dissolves in aromatic solvents. It also has low resistance to UV and turns rapidly yellow (3–6 months) when used in lighting products or outdoors.
The highest temperature at which it can be used is limited to approx. 70 °C. The material is not authorised for lighting fittings for professional use, especially high powered ones or those with long burning times. The material is often chosen for domestic applications due to its low material costs.