ok, I know this is a bit of topic but...
my friend & her hubby bought her house off plans (before it was built) about two years ago. They insisted on extra insulation to be put into the walls, both external and internal. You really can feel it: house is warmer and so much quieter than their neighbours. And it added a massive 500euros to their final house price. In generel builders cut the corners everywhere they can, save time, save material - build cheap, sell expensive. And we have to live in that.
We're renting 10years old house with market value of approx 600,000eur and in my eyes it's not worth even a third of it. it's impossible to heat up in winter, it's noisy, low quality finish and I could on and on and on... When we are ready to buy our own place we're gonna go for a 'project' house and then do it up to our liking and standards. End of rant.