hello hapless101, my EM is still goin thru with its reno, i have the same issue like yours too, quotation from my contractor incl sealing up the opening with top swing casement windows, the initial cost was $1250, but the approval from HDB requires the change of window's material to laminated glass - which blows the cost to almost $2k. so i asked the contractor to resubmit the application to do fix panel for top half of the opening, and window up the bottom half, hopefully to cut the cost alittle. yes, it will be almost impossible to operate the windows after its installation, so you may just wanna keep the windows opened to an optimal angle and just leave 'em. this is the best solutions i got from other EM'ers so far. hope this helps. kind regards, stanley