REVIEW AND ANALYSIS 29 too cold, but another busy with the housework may feel much too hot. In summer, heat-absorbing surfaces help occupants cool down, and nasty draughts become pleasant breezes. LEARNING FROM THE PAST As we realise the importance of radiant loss of body heat, it makes sense of what we see in illustrations of interiors predating the Industrial Revolution. In winter a ubiquitous feature was walls covered with drapery, cloths used to partition spaces, rugs on the floor, and canopies of cloth and wood, as well as barrel-vaulted ceilings and wooden panelling. Unlike stone, brick or mortar, cloth and wood warm almost instantly as we radiate into them, after which they stop absorbing our heat. A cloth between an occupant and a stone wall acts as a radiant break, slashing the huge amount of body heat we would otherwise be losing into the massive wall. The effect this has on comfort is easy to feel – simply drawing a light net curtain across a glazed window in winter produces an instant improvement – but it is extremely difficult to measure. Certainly radiant breaks will have little effect on the temperature of the air. Medieval images show how cloth and timber created ‘cosy corners’ for scholars and others sitting quietly. Paintings of festivities show canopies and tents over the musicians and cloths draped behind honoured guests, while dancers benefit from the cool bare floors and walls. We know from housekeeping records that cloths were often taken down in summer when radiant heat into solid walls was beneficial, and so it is not surprising that so many wall paintings are fictive draperies. Fireplaces in use are invariably shown associated with cooking, although there can be little doubt that the warm glow and crackle of a fire was at least as comforting then is it is to us now. When not being used for cooking, fireplaces are often shown sealed with wooden panels. But although they used screens and drapes to control ventilation, they did not try to eliminate it. Indeed, it is clear from books that air movement and air exchange was desirable, for health reasons as well as comfort: But Lark Rise must not be thought of as a slum set down in the country. The inhabitants lived an open-air life; the cottages were kept clean by much scrubbing with soap and water, and doors and windows stood wide open when the weather permitted. When the wind cut across the flat land to the east, or came roaring down from the north, doors and windows had to be closed; but then, as the hamlet people said, they got more than enough fresh air through the keyhole. Flora Thompson, Lark Rise Now, in contrast, we attempt to achieve comfort by heating and cooling the air, sealing and superinsulating our building envelopes to prevent this air from being lost, resulting in serious problems of mould and bad indoor air quality. Comments such as Flora Thompson’s and medieval images are often interpreted as showing our ancestors were much hardier than us. But there is more going on, if we go back to thermal physiology. For a start, appropriate clothing, draperies and rugs and so on were able to relieve so much of the thermal discomfort that the temperature of the incoming air was largely irrelevant. Secondly (as highlighted in the paper by Pallubinsky and others, and confirmed by many other studies) our thermoregulatory systems become moribund if not exercised. This not only makes us prey to health problems such as heart disease, obesity and diabetes, but also increasingly unable to respond quickly and effectively to changes in the environment. In other words, the more we live and work in tightly controlled thermal conditions, the more apt we are to feel uncomfortable; or worse, to suffer serious health problems from exposure to very hot or very cold conditions. With climate change already leading to extreme weather events, the global north penchant for constructing buildings that require heating and air conditioning begins to look even more unwise. As fuel prices increased, the sales of personal comfort items such as heated blankets exploded, but they have not slowed despite the cost of central heating dropping again; indeed, Wall cloths, bed hangings and an open window illustrated by the Flemish painter and illuminator Barthélemy d’Eyk in the mid-15th century (Codex Vindobonensis Palatinus 2617, detail)
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