When upgrading how many days per level for the Mountain Chateau?

Each level in the Mountain Chateau has 24 steps, which means it'll take 12 days if you renovate every 24 hours (10 days if you renovate every 20 hours). There are 19 levels to complete (done when you reach level 20), so it'll take 228 days total if you renovate every 24 hours (190 days if you renovate every 20 hours).