Not so sure about it being closed because of HVAC issues, they have been really struggling to get guests. I am assuming that the franchise agreement with Hilton only allows them to be closed for x amount of time per year, in order to avoid penalties it's probably better business to be open at very high nightly rates and zero guests then to offer reasonable rates (it's been going for € 45-60/night for most of 2020 IIRC - which is probably not enough to cover expenses) and run the hotel at a loss.