I have had two Airforce portable aircon units (model WAP358DB) for several years using them occasionally every summer. They have been very efficient and reliable but are quite large, (470W x 300D x 900H) suitable for a bigger room but I expect there are smaller sized models. Like all aircon units (unlike cooler units) they require an external vent to exhaust the hot air. This is a flexible pipe normally 100-110mm diam, the ones I have end in a rectangular fitting. I found the easiest way to arrange this is either: - If you have a redundant fireplace/chimney breast cut a hole to insert the exhaust hose. - If you have a sash window raise the lower leaf, insert a piece of wood across the window frame and lower the leaf down to hold it firm. Cut a hole in the wood to receive the end of the exhaust hose. If you want to avoid having to empty the internal water tank then drill a hole through your outside wall for the drain hose. You can plug this with a cork when no longer needed or use a pipe with, for example a drain cock, for a more permenant soltion. (If you are not on the ground floor then fix the drain cock inside the room not on the exterior wall where it won't be reachable).