Our medieval ancestors have much to teach us of thick walls, middens, shutters and chimneys
Domestic life in the past was smelly, cold, dirty and uncomfortable, but we have much to learn from it. I spend much of my time working as a curator in Britain's historic royal palaces. But recently, for a television series, I've visited a lot of normal homes dating from the Norman period to the present day, and I've concluded that the houses of the past have a huge amount to teach us about the future. When the oil runs out, I think our houses will become much more like those of our low-tech, pre-industrial ancestors.
The first point is that the age of specialised rooms is over. Now, legislation governing the design of new houses contains echoes of the past: it insists that once again rooms should multi-task. The living room, for instance, must have space for a bed in case the occupant becomes incapacitated; medieval people, for instance, lived, ate and slept in one room – as I do, in my open-plan flat.
Next, architectural features from the past will start to reappear. The chimney disappeared in the 20th century, but it's coming back, as solid fuel-burning stoves make a return. In terms of fuel conservation the sun is becoming important again too: once upon a time people selected sites with good "air"; now well thought-out houses are situated to minimise solar gain in summer and maximise it in winter. Most future houses will need to face south, a challenge to conventional street layout.
The return of the chimney also serves to allow natural ventilation – even where there aren't fireplaces – lifting stale air out of the house. Mechanical air conditioning uses valuable energy, and will soon be simply unaffordable.
Walls are getting thicker too, again like those in the medieval era. Buildings then had thick walls because they were easier to build – but also because they provided good insulation. Windows will grow smaller again and houses will contain much less glass – not only because of the high energy costs of glass but because it's thermally inefficient. I live in a glass tower built in 1998, and agree with Francis Bacon, who condemned the glass-filled palaces of the Jacobean age. In a house "full of glass", he wrote, "one cannot tell where to become to be out of the sun or cold".
The return of the shutter is also likely: it's the best way of keeping heat out of a house. And with a hotter climate we'll probably experience water shortages. Our daily water consumption is about 160 litres; the government expects us to get down to 80 – the equivalent of a deep bath – by the end of this decade. We'll eventually need to grow as water-thrifty as the Victorians, with an average use of 20 litres a day. The Victorian cook was also a terrific recycler of food; the earth or "midden" toilet has already been revived in the form of the ecologically sound composting loo.
More significantly than the return of shutters, chimneys and middens, there's a revival in the use of natural building materials, substances with small environmental footprints like wood, wool insulation and lime mortar. In the last decade timber-framed houses have started to sprout up across Britain.
We'll likewise become more medieval in re-using, adapting, and making additions to our houses. In an island short of space it's been calculated that we need to build 200,000 homes a year to cope with a growing population. According to Empty Homes, there are 700,000 homes standing unoccupied in Britain. It's obvious that we need to get them back into use. Medieval and Tudor people didn't treat buildings as a semi-disposable resource like we do.
But we also need to think about what makes a community. Today's builders and town planners believe people inhabit "places". Yet medieval towns were perfect examples of what planners seek: densely populated, walkable communities in which people ate local, seasonal food, and rich and poor lived in close proximity.
A successful "place" mixes different groups. In this sense Hardwick Hall, the Elizabethan mansion, was successful social housing. Bess of Hardwick, its chatelaine, slept within metres of the people in her employment. It was a life of huge inequality, but she had responsibility for the poor and the sick, and they were all part of a common endeavour.
This sounds conservative – but it's radically so. We've spent too long inside our snug homes looking smugly out at the world. The dwindling of natural resources will force us to change. But that need not frighten us: the pleasures of domesticity are perennial. As Dr Johnson put it, "to be happy at home is the ultimate result of all ambition".
• Lucy Worsley presents If Walls Could Talk on 13 April, at 9pm, BBC Four