Are there any wood-burning steel firebox places that don't generate warmer than the conventional old-style stone fireplaces?

We are preparing to get a timber losing flame place developed here and the designer recommended I look into flame place places or as he put it 'metal boxes' as they are much less expensive to set up. From my very restricted knowing of these they seem to be developed, through the use of flame supports and convection compartments, to generate much warmer than a frequent old developed stone start fireplace. Is this correct? I'm asking because we are seeking the fireplace more for the atmosphere and as an attractive function rather than a heating unit (though we still want a wood-burning one not one that burns gas or ethanol). Are there any fireplace mount styles that don't generate any warmer than a frequent fireplace, or even generate less?

tv over fireplace : over fireplace mount : fireplace flat panel