Yes. Pet hair and dander causes blockage of the filter and can also cause blockage of the indoor coil. Any obstruction in the system will lower the system's performance and efficiency. Doggie doors create more heat gain for the home because they have no insulation. A great deal of heat and hot air infiltration can be gained through these small doors. Large fish tanks have been seen to increase humidity in homes; therefore, making the unit run longer and harder to reduce humidity levels. This leads to increased energy consumption and higher energy bills.