It takes less energy to keep the water in a hot water boiler hot than it does to keep filling and reboiling a kettle. It is also true that a hot water boiler becomes cheaper the more it is used, so it is the perfect solution for larger offices, canteens and canteens.
A hot water boiler will also save you money in terms of man-hours, as your team will no longer spend time waiting for the kettle to boil.