states that all installed electric heating products manufactured from 1 January 2018 must have an electronic thermostat with a 24-hour, 7-day timer with either adaptive start or an open window sensor. Storage heaters must include: an electronic heat charge control with room and/or outdoor temperature feedback or controlled by energy supplier, an electronic room temperature control plus week timer and a fan assisted output. Optional additional compliance features are distance control, adaptive start and open window detection. Non-compliant stock that was manufactured before this date may still be sold. From an environmental health point of view, asbestos has been used in night storage heaters for many years, the fibers of which can get into the air and pose considerable negative health impact. Application Storage heaters are usually used in conjunction with a two-tariff electricity meter which records separately the electricity used during the off-peak period so that it can be billed at a lower rate. In order to enjoy the lower rates, the house must be on a special electricity tariff. In most countries, storage heaters are only economical (compared to other forms of heating) when used with such a special tariff. In the United Kingdom the Economy 7 tariff is appropriate. Storage heaters usually have two controls: a charge control (often called "input"), which controls the amount of heat stored, and the draught control (often called "output"), which controls the rate at which heat is released. These controls may be controlled by the user, or may operate automatically once the user selects the target room temperature on a thermostat. Storage heaters may also incorporate an electric heater (utilizing either resistance heaters or heat pumps), which can be used to increase heat output. Such added heating, if it is resistance heating, is expensive, as it occurs during the high-tariff time of day. Comparison to other heating systems Advantages Storage heaters, while often still more expensive than equivalent gas- or oil-fired heating systems, are cheaper than running the same amount of electrical heating using electricity at regular daytime rates. Users of gas central heating and some other systems often turn off the heating during the night as an economy measure, with the result that the house is cold at night and early morning; but because night storage heaters are on at night, the house is still warm at those times. Using storage heaters allows houses to be sited in areas where