What is the minimum diameter recommended for A/C condensate drain hose?

The minimum diameter recommended for an A/C condensate drain hose is 5/8 inch. This size is effective for ensuring that condensate can drain away freely from the air conditioning unit without risk of clogging. A diameter of 5/8 inch strikes a good balance between allowing sufficient water flow and minimizing the potential for blockages that can happen with smaller diameter hoses.

Using a diameter that is too small can lead to restrictions in drainage, resulting in water backup, which may cause damage to the unit or surrounding areas. Additionally, the 5/8 inch size allows for compatibility with standard fittings and maintains a manageable weight, making installation easier.