Condensation in buildings is mainly a winter problem particularly where warm, moist air is generated in areas of occupancy and then penetrates to the colder parts of the building. This can result from a number of things in both residential and commercial buildings including cooking, bathing, washing dishes and/or clothes, heating, humidifying, etc.  Condensation may be more acute in buildings with inadequate ventilation.

In relation to Solatube Daylighting Systems, the condensation occurs when warm moist air enters into the tubing. Most likely, if there is condensation occurring in the Solatube Daylighting System, there is probably condensation around other parts of the building such as on windows, doors and skylights.
Because there are so many variable factors that may contribute to condensation in a home, Solatube International, like most window and skylight companies, does not cover condensation under the manufacturer’s warranty. 
Recognizing that condensation cannot be eliminated, Solatube International has made design changes to its Daylighting Systems over the years to help address this subject.  Your local Solatube specialty dealer is best suited to determine if these improvements or other modifications will help minimize condensation in your Solatube Daylighting System. Please be aware that because condensation is not covered under warranty, there may be a charge for the service call and/or additional parts.  Your Solatube specialty dealer may suggest adding additional components that have been developed to minimize condensation such as a Dome Upgrade Kit, Flashing Insulator, Climate Control Lens or Severe Climate Glazing.