My PC case has a solid front panel and I wish to install 2 fans ( 1 inlet and 1 exhaust) to decrease the temperatures. I know front panels are supposed to have mesh to increase air flow but mine is solid. Does installing the 2 fans help decrease the temps or make it worse?
Front fans can hurt depending on the chassis' design.
A real good example is the Bitfenix Enzo, which, if the user used front intake fans - since the fans couldn't 'breathe', what they'd do then is 'grab' the already warmed air inside the chassis and recirculate it over and over...
NZXT's H500 is another one. This one was designed around negative pressure(exhaust > intake), and the installation of front intakes works against that design to the point that it either changed nothing(it's possible neutral pressure was achieved), or made thermals worse.