Over the span of about 8 years, I went from living in a < 1,000 sq-ft house built in 1951 (that I added extra attic insulation to) to a 2k sq-ft one built in 19

Over the span of about 8 years, I went from living in a < 1,000 sq-ft house built in 1951 (that I added extra attic insulation to) to a 2k sq-ft one built in 1976 to a 3k sq-ft one built in 2003. Even though each house was successively larger, the heating and cooling bills were noticeably lower in each case. Building practices matter. Insulation and modern windows matter!