Maybe drop the wall to the very top of the heater and then put the railing on top of that.

@palimpsestThat was kind of my thought. not sure if itll look stupid doing it that way but maybe if i do like a nice trim on the bottom it wouldnt be too much wall left and you prob wouldnt be able to tell at all from the living room area

What do you plan to use that loft space for ?

@Patricia Colwell Consultingits the second floor theres a full bath and 2 bedrooms upstairs. i just want more of an open feeling from downstairs.

What kind of heater is it? If it’s just a long heater with a duct, replace it with a floor vent. If it’s an electric heater, not a big deal to move it to another wall. Just guessing, but thinking you may not even need it for a loft space unless it provides ac too.

To me, it looks like baseboard hot water

You did not answer the question . The space needs to have a purpose before opening it up to be seen from below. Yes we need to know what the heat is but I think the idea of removing to the top of the hetaer and replacing the wall with glass might be good viually but only if you plan on having nothing on that wall