The NHS has issued guidance advising people aged over 65 to set their heating to at least 18C this winter, with temperatures up to 21C potentially beneficial, as energy bills are forecast to rise sharply.
Ofgem increased the price of gas and electricity by 4% in October, and January is expected to bring further increases, with forecasts suggesting bills could rise by as much as 24%, equivalent to a £400 a year increase for a typical household.
Health risks of cold homes
In a paper titled 'Minimum temperature threshold for homes in winter', the NHS outlined how indoor temperatures can affect health, noting links to various conditions and highlighting the specific needs of older people.
The guidance stated: "Cold weather is not only associated with an increase in deaths but also has a significant impact on morbidity. Many population groups are particularly at risk from cold temperatures; vulnerable groups are widely distributed within the population and include older people, children and those with chronic illnesses, particularly cardiorespiratory disease."
It added: "It is those most vulnerable to cold, who also spend the majority of their time indoors at home and may not always perceive cold temperatures because of physiological changes that occur particularly with ageing."
Evidence on temperature thresholds
The NHS reviewed available studies to assess whether existing advice remained valid. It found that indoor temperatures of at least 18C pose minimal risk to a sedentary person wearing suitable clothing, while temperatures below this could lead to negative health effects such as increased blood pressure and a higher risk of blood clots, which can cause strokes and heart attacks.
One study cited in the review showed that residents of the coldest 25% of homes have around a 20% greater risk of dying during winter than those in the warmest homes.
Higher temperatures for older people
World Health Organisation guidance recommends an indoor temperature of 18C, but suggests temperatures 2-3C warmer in rooms occupied by older people due to their more sedentary lifestyle.
The NHS review noted: "This review has failed to find hard evidence that temperature thresholds above 18C are required for older people. However, since older people have weaker thermoregulatory systems and have more profound physiological responses to cold, as well as being less able to detect cold or falling temperatures, there is an argument for advising slightly higher indoor temperatures in this age group."
It concluded: "Emphasis should be placed on keeping the homes of vulnerable people to at least 18C, but that temperatures up to 21C may be beneficial. Younger healthy adults may find it easier to increase activity levels and adjust their clothing to keep warm, and may wish to keep indoor temperatures to levels at which they are comfortable, even if this is lower than this threshold."
