 To maintain a comfortable temperature inside such a large glass building was another major challenge, because the Great Exhibition took place decades before the introduction of mains electricity and air-conditioning.Glasshouses rely on the fact that they accumulate and retain heat from the sun, but such heat buildup would have been a major problem for the Exhibition, and this would have been exacerbated by the heat produced by the thousands of people who would be in the building at any given time.Paxton solved this with two clever strategies.