They didn't have air conditioning, but the room we were in -- a top floor balcony room, overlooking the inner courtyard was completely in shade, and last Saturday it was sunny all day with a max temp of 25C, and the rooms were not at all hot, so it wasn't an issue.
As for parking, I don't know what the arrangements would be, as we took the train in from the airport and used the underground and trams thereafter. The hotel is on quite a busy road and I don't think there were any spaces right outside, but there were residential streets nearby which might offer parking, free or relatively cheaply. It's not a city centre hotel, so the parking wouldn't be very expensive if you did pay for it. It didn't look to have its own on site car park, but I guess they might have some arrangement with a local car park.
Generally it was a very good hotel, especially for the price and ease of access to the U2 train line, which is by far the best way to get into Berlin city centre. Only €1.60 each I think for a single fare.