Yes, this unit can be used in California. However, we still recommend checking with your local code as state wide and local codes can differ. For example, this furnace does not comply with the SCAQMD Rule 1111 nor the SJVAPCD Rule 4905 14 ng/J NOx emission limit and therefore is not eligible for installation in California’s South Coast Air Quality Management District (SCAQMD) nor the San Joaquin Valley Air Pollution Control District (SJVAPCD). If you have any further questions please feel free to give us a call! Thank you.