The cheongyak (housing subscription) account deducts 40% of up to 3 million won paid in a year, capped at 1.2 million won. That is income removed, not tax refunded — at a 15% bracket it cuts the bill by 198,000 won.
Earn ₩55 million or less and you get 17% of your rent back; earn more and it drops to 15%. On ₩600,000 monthly rent that is ₩1,224,000 versus ₩1,080,000 — a ₩144,000 swing on one won of salary.
Korea's wolse (monthly rent) tax credit returns 15–17% of rent up to 10 million won a year for renters earning under 80 million. The cap bites at 833,000 won a month.
Korean renters earning up to 80 million won a year can claim 15-17% of annual rent (capped at 10 million won) as a tax credit - up to 1.7 million won back.