Keep in mind that with proper care, these doors can last a lifetime. Even without an insulated core, installing a new wood door will lower your heating and cooling bills and reduce drafts and outdoor noise. Most energy loss at an old door is not through it. It is mainly from air leakage around it. The best wood doors come with double and triple weatherstrip seals.
Some manufacturers use triple-pane glass.
This is a good choice in all climates because the expensive decorative center pane has protective panes of tempered glass on each side of it. If you want a highly insulated door with the beauty of real wood, several manufacturers offer wood doors with insulated cores. Seeing and touching it, you would think that it is all wood. Many high-quality wood doors use stile and rail construction with mortise and tenon joints. Since wood expands and contracts throughout the year, many designs use decorative floating panels.