system
A chat on subreddit /r/NoStupidQuestions
human
In a lot of places people with money buy cheaply built but huge houses.   I'm not talking about those McMansions when I mention good insulation, energy efficient appliances, and energy efficient heating and cooling (including water), as well as good quality windows.   That up front investment ends up paying off in the long run and has the added benefit of being more environmentally friendly.
gpt
This.  I design houses (mechanical) and in my experience, people think every large house built by a developer in a planned neighborhood is automatically a McMansion.  But it's the unseen details that really make a difference.  For example, my interior walls are insulated.  Who TF insulates interior walls?!  I don't know but it's awesome if you have kids that like to jump around everywhere and yell all the time.  I don't live in a mansion but it's a decent sized house.  And it's not without it's cheap accoutrements (low SEER HVAC equipment).  But in my line of work I've seen A LOT worse for houses just as large.