natural-gas distribution systems are not available, without requiring the homeowners to pay higher daytime electrical-heating bills. The capital cost of night storage heating is relatively low, and installation is far easier than the initial installation of gas-fired boilers, piping and radiators, or electric heat pumps. This is an important advantage when renovating old buildings without existing central heating. As compared to gas central heating systems, night storage heaters have next to no maintenance costs. Disadvantages Heat is lost from the heater while charging overnight. The room is warm in the morning, but this is because it has wastefully been heated all night. The heat stored during the night will be released into the living area during the next day, regardless of need (due to the inevitable heat transfer through the storage heater's insulation). Thus if the homeowner is unexpectedly absent that day (and therefore does not need the house to be warmed) or is only at home for a small part of the day, the heat has already been purchased and is already there, and eventually comes out. The storage heater can only heat with the energy stored the night before. Thus if the system was switched off or if the charge control was set too low, there may not be sufficient energy to heat the rooms, and this can only be corrected for the next day. This is a problem for example when the weather turns cold unexpectedly, or when returning from a vacation late at night, or users simply not thinking to change the settings because they are at a comfortable temperature. Some heaters alleviate this problem by also allowing heating during the day, but this is typically expensive (because the electricity is charged at full rate). Even under the best of circumstances it can be difficult to accurately judge how to set the thermostats as setting them too low overnight can cause the heater to be having no perceived effect while setting them at maximum will increase the cost of running them. Similarly in systems where every heater must be set individually, incorrectly setting one room's heater can make the whole house feel too cold. Many users may not fully understand the controls. A common error is leaving the output (or boost) control open at night, so that the heaters dissipate heat when they should be storing it, with a consequent increase in electricity consumption and cost.