Missing insulation reduces the system’s efficiency. Insulation helps hold heat in the system, and when the heat can dissipate, more fuel is needed to maintain proper temperature and pressure.
Since missing insulation may not be visible, the best way to detect it is with a thermal imager. If you don’t have a thermal imager as a part of your building’s operations, a plumber or other professional likely will carry one. If your energy costs have increased without a rise in the amount you use the boiler, suspect missing insulation and call to have the system inspected with a thermal imager.