Re-done rooms now much hotter
If it was worse insulation, the room would be colder in the winter and hotter in the summer.  

If it's hot all the time, that's an energy burn inside the room.  What is the wattage of the various lightbulbs?   

If they are not LED, it's time.  Boilerplate primer on LED buying: Think carefully about color temperature and CRI, 2700-3000 and 80+ are good choices for homes.  I just installed a ton of those and nobody can tell they aren't incandescent, except of course that they are 6 watts.  Buy GE, Cree, Philips or Ikea.  Don't buy Lights of America, Utilitech or Feit Electric, no matter how good the price is.  Choose wisely, you won't be replacing them for a very long time. 

Do they own a home computer?  What kind? Did they change it recently?