There are a few typical sizing options to choose from when it comes to solar tubes. You want to make sure you are choosing the best size for your home's needs. Here's a quick overview of the available sizes: 1. 250 mm solar tubes cover up to 10 square meters, which is ideal for both bathrooms and hallways. 2. 350-400. The main purpose of a solar tube is to efficiently transfer outside daylight into your home. These tubes will not offer outdoor views, but they will. Here are three of the biggest benefits of installing solar tubes: 1. Save on electric bills 2. Good for the environment 3. More natural light A solar tube comes in a 10 inch-diameter, and also in a 14 inch-diameter tubethat has a polished interior and made of sheet-metal. These are also. Solar tubing is always priced by diameter size and may vary based upon manufacturer. With that being said, homeand business owners should expect to pay the following for.