Fungus expert Jos Houbraken of the Westerdijk Fungal Biodiversity Institute said that leaving homes unheated during the winter can increase the risk of fungi developing. Although fungi generally grow more slowly at lower temperatures, cold air holds less moisture, which can raise humidity indoors. Fungi can cause health problems and allergies or worsen asthma, he said.

Houbraken advised keeping homes warm, ventilating them well, avoiding indoor laundry drying where possible and ventilating after showering. He also recommended leaving space between furniture and walls to improve airflow and reduce damp spots. The Emergency Energy Fund is expected to provide help during the coming winter for people who cannot afford to raise their heating.