Window tax was introduced in England and Wales in 1696 under King William III. It was designed to impose tax relative to the prosperity of the taxpayer, but without the controversy that then surrounded the idea of income tax. At that time, many people in Britain opposed income tax, because they believed that the disclosure of personal income represented an unacceptable governmental intrusion into private matters, and a potential threat to personal liberty.
When the window tax was introduced, it consisted of two parts: a flat-rate house tax of 2 shillings per house (equivalent to £12.11 in 2014), and a variable tax for the number of windows above ten windows in the house. Properties with between ten and twenty windows paid a total of four shillings, and those above twenty windows paid eight shillings. The flat-rate tax was changed to a variable rate, dependent on the property value, in 1778. People who were exempt from paying church or poor rates, for reasons of poverty, were exempt from the window tax. Certain rooms, particularly dairies, cheeserooms and milkhouses were exempt providing they were clearly labelled, and it is not uncommon to find the name of such rooms carved on the lintel. The bigger the house, the more windows it was likely to have, and the more tax the occupants would pay.
Architects responded to the tax by designing houses with fewer windows, and careful or impecunious householders bricked up some existing windows. As early as 1718 it was noted that there was a decline in revenue raised by the tax due to windows being blocked up. In 1851, it was reported that the production of glass since 1810 remained almost the same despite the large increase population and building of new houses. The complaints from the medical profession and enlightened individuals rapidly grew as the industrial revolution and urbanisation created mass housing and crowded cities, and raised the spectre of epidemics. They argued that the lack of windows tended to create dark, damp tenements which were a source of disease and ill-health. The campaigners argued that it was a ‘tax on health’, and a ‘tax on light and air’, as well as being an unequal tax with the greatest burden on the middle and lower classes. The campaigners eventually won the argument and in 1851 the Act was repealed and replaced by a house tax.