I've wondered if it might be more energy efficient to build home systems more like commercial ones. Make it walk-in but with a double door so you don't spill a

I've wondered if it might be more energy efficient to build home systems more like commercial ones. Make it walk-in but with a double door so you don't spill all the cold air when you open it. The freezer spills into the refrigerator so the cold isn't lost. Since it's built in size is of minimal importance and you can put a lot of insulation on it.