Hello, there, i have 2000 square feet one-story house, and my old return air vent is on the living room floor, only 16x8 inches used to cover 1100 square feet. Now that I expanded my house to 2000 square feet, however, My contractor did not increase the return air vent. I really suspect he was cutting corners by not replacing the old return vent, which will hurt the heater performance. I only have hearted, no A/C in the house.

Does anyone know what is recommended size for return air vent for a 2000 square feet house? thanks so much!