Shutters Vs Noise & Heat
Internal window shutters do provide a greater reduction in noise and heat compared to any other internal window treatment, such as blinds, venetians etc.
However, even though they do reduce noise, shutters are not a dedicated sound proofing treatment such as double glazing.
Think of it like putting a sheet of plywood over your window opening , that is the equivalent of shutters, as all louvers overlap each other and all frames are rebated behind shutter panels a full noise barrier is achieved.
Heat Reduction with Shutters
With regards to heat the same is achieved as all heat coming into your home through your window glass is trapped between the back of the shutters and the glass, this helps prevent the heat from seeping into the room.