Water Based chimney saver is the most popular version and is able to be applied to damp surfaces so you don't have to wait for a dry day. Non-Combustible with no chemical odor. Water based Chimney Saver is VOC compliant in all states .
If the chimney has been previously treated with other types of water repellents, solvent based Chimney Saver is recommended.
There are also block VOC compliant solvent base, block chimney specific, and stain blocking versions (for chimneys with mold or algae growth issues).