The tenants in one of my rental units is complaining that the 3 window air conditioners that were already in the unit when they moved in are not sufficiently cooling the entire house. They are asking me to replace one of them and purchase a fourth one. Am I responsible for this or do I tell them to maintain it themselves and buy their own if they want another one? I never advertised the place with air conditioning although on the listing website it did have a box that I checked that window air conditioners were existing. Thanks for any help with this!