It's ABC's Extreme Makeover: Home Edition. I don't think the 'Fix You' is referring to the houses themselves, but rather the people they're being built for. The show generally picks less fortunate people - i.e. widows/widowers with a lot of kids, cancer patients, paralysis victims, et al - and tries to make their lives better via a brand new, large home with situation-specific designs, items, rooms, etc in them. At least that's what the idea of the show is. So the 'fix you' is probably more aimed at the people who will be moving into these homes.
I still don't much care for the song though.