Perhaps an opportunity to drag a relic of the past back into use by cutting a hole in the floor above that basement room and putting a decorative register/vent on the higher floor to walk upon.

That used to be common before the advent of forced air and the various radiant home heating systems; the idea is you depend upon the stack/"chimney" effect (hot air being more buoyant than cold). A matter of ensuring the register is large enough for cold air return and/or some other path exists such as an open interior door to the basement. Think fireplace design.