Hi @Kathryn68
If the windows are open, and that makes the house not secure (if you are on the ground floor or 1st floor, for example), and If I was in your position, I would text the guest and inform. Something like:
@"Hello XXX, We noticed this morning that you left the (bedroom / living room, etc) window open. For your security, and of your belongings, we entered the room and closed it.
Once there, we noticed that you left TV and air con on. To help the environment, we took the opportunity to turn it off.
Please be mindful and please make sure that windows are closed and that lights and appliances are turned off when you leave the airbnb.
Thank you for understanding.
XX)