Loft insulation will save you 15-20% per year of your heating bills. If you live in a house with solid walls this measure is the best way to make your home more energy efficient. We also insulate any pipes or water tanks that are in your loft to guard against any burst pipes or leaks.
Some lofts may require additional ventilation because with less heat escaping through the ceiling into the loft and out the roof means less air circulation. By installing additional vents this takes away any possibility of condensation problems that can arise if not fitted.