korean: 물론 옛집을 더 효율적이게 고쳐서 썻겠지요. 그 경우라면 회복하기에 20년 정도 걸릴것입니다.
english: Now, I probably would have upgraded the old house to be more energy-efficient, and in that case, it would take me more about 20 years to break even.