Outbound flight to faro OK as we had exit seats. the return flight was another story! we started with a 2 hour delay. when we boarded the aircraft it was very hot, no airconditioning was working for the first 30 minutes. passengers had been given seat numbers that did not exist which caused a lot of of confusion. the plane was very old and very dirty it was an MD83 type aircraft. there was no legroom between seats so much so I could not open my paper to read it. we had very poor cabin service, cold tea, the ovens where out of action so we had no hot food. we had no interaction with the pilot even though we flew over a lightening storm which some people found very frightening. we seemed to be circleing dublin airport for nearly 40mins again no contact with the pilot as to what was happening. we have made sunworld aware of what happened as we feel our safety was at risk and won't use this company or aircraft again.