Upvote:2
There are a lot of online resources about altitude sickness prevention. Like TripAdvisor or the NHS (National Health Services from the UK government). They all give similar advices, which include, among others:
Hydrate yourself more often than you're used to.
I couldn't find an online resource which mentions windowless room as a measure against altitude sickness. If it was effective, probably someone or some health agency would have suggested it.
I suggest you to pick the cheaper windowless room and take other more conventional altitude sickness prevention measures.