Solid door or polystyrene filled ?

For an external door to a room within a room in a single brick garage conversion Someone has given me some of these doors that are wooden but filled with foam/polystyrene. Just wondering if I should use them or go for a solid wood door There will be 2 doors with a foot of gap in between Cheers Andrew

Mass is what you want so the solid core is the better choice by far.

Cheers.