Central heating really took off in the UK from the early 1970s, and it has become ubiquitous since then – a survey conducted in 2004 (which I am going to mention very very briefly, as it technically contravenes our 20 year rule) showed only 7% of British homes lacked it by that date.

Several factors combined to make central heating a more common choice after the 1960s. These included the construction of new housing; changing habits of dressing; the vogue for open plan offices (which require much more powerful forms of heating to maintain a steady average temperature than old single-occupancy offices, which could easily be heated by a radiant heat source); the spread of double glazing and improved loft insulation (which together significantly reduced heating costs overall); changes in leisure habits; and the long term consequences of the passage of the Clean Air Acts of 1952 and 1968.

To take the last of these factors first, the first of the Clean Air Acts was introduced in the aftermath of the infamous London smog of 1952, which was caused by an anticyclone hovering over the city and trapping particles of pollution from coal fires, and which is estimated to have killed around 4,000 people. It mandated the use of smokeless fuels within designated areas, which increased the costs of the traditional coal fire heating then common in the UK.

Equally if not more significant was the 1960s and 1970s change in fashions that led to people abandoning dressing with multiple layers (u/mimicofmodes may be able to supply more context here), and this combined with an overall increase in affluence, which made what had once been costly heating options more affordable. Thus the average temperature inside a British home in the 1950s was 18 degrees C, while now it is 22 degrees.

Finally, I mentioned changes in leisure habits. Hard though it is to imagine at this relatively late remove, the UK had only three TV channels into the 1970s, and these stopped broadcasting in late evenings, leaving only "dead air" in their stead. This meant typical bedtimes were actually earlier in this period, and people tended not to stay up late in the winter months as their homes became colder as the evenings progressed. The advent of more TV channels, 24 hour TV, computers and computer games radically changed sleeping patterns, encouraged more people to stay up later, and so also encouraged the purchase of central heating systems to efficiently heat homes late into the night.

Similarly, the advent of central heating changed the ways in which families interacted – replacing one heated communal living space (a kitchen or living room) in a home in which the rest of the house was kept much cooler, to save money, with homes in which all rooms could easily be kept at the same temperature. The phenomenon of kids having their own private spaces in which they could comfortably stay up late or get up early – usually centrally heated bedrooms – was largely unknown in 1960s and early 1970s Britain, when whole families congregated together in small, but well heated, living areas. But, once it became common, it proved very hard for many families to dispense with. Hence, existing homes were supplied with central heating, and, when families moved, they tended to exclude homes that were not centrally heated from consideration, encouraging other home owners to upgrade.

While personal anecdotes are rightly discouraged here, I can use my memories of visiting grandparents who lived in a terraced house in a Welsh mining village in the 1960s and early 1970s to point up the ways in which less affluent families would heat homes in this period. There was no central heating, but – unsurprisingly – ready availability of coal, which was delivered monthly and kept in a special bunker outside the back door, to be fetched in coal scuttles as required. The lavatory was located outdoors and was completely unheated, encouraging rapid bathroom visits. The living room was small (about 10 foot by 8 foot) and kept at a high temperature by a roaring coal fire, while in winter the rest of the house was at least 10 degrees cooler. The bathroom was unheated except for a light fitting equipped with a special radiant heat bulb. Bedrooms were chilly and supplied with metal bedwarmers (which held hot coals) into the 1960s, and with electric blankets thereafter. Leaving the living quarters and getting ready for bed in winter time involved making preparations in advance (turning the bathroom bulb and the electric blanket on half an hour before they would be needed) and necessitated several quick dashes from lavatory to bathroom to bedroom, and a final hasty dive into bed. Mornings were partially taken up with the chore of cleaning the grates from the previous day's fires and building new ones. All this made the attractions of switching to central heating as if became available and affordable both obvious and compelling.