I have zero doubts that the average American house is way, way too big and consumes far too much energy (in its construction, and especially through its use), and produces far too much waste. This is a huge problem.
Thankfully, there is now a shift towards a tiny house movement, with some forward-thinking folks designing, building, and residing in ever smaller homes, in opposition to the “bigger is better” mentality that has plagued modern American homes. But when is small just too small to be practical? How realistic are tiny homes for a non-consumer lifestyle?