Energy efficiency

Howtemperature and humidity promote comfort

Fan Wang, a building physicist and lecturer at Heriot-Watt University, discusses the findings of a series of studies carried out over the past three years, which focus on temperature, humidity and comfort in care homes and offers some practical solutions to ‘winter dry’

As winter approaches, maintaining a comfortable room temperature, while keeping energy costs under control can become a concern in elderly care. There are no clear standards to follow as commonly used comfort standards, such as those from the Chartered Institute of Building Services Engineers (CIBSE) in the UK and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) in the US, address the needs of healthy young adults in normal buildings. In a care home environment, it is common to set the thermostat to high to keep residents happy, as it is understood that older people prefer a warm room. However, this simple and seemingly effective solution can have some less positive effects, which are often overlooked. One problem is of course high energy consumption, which leads to higher electricity bills and higher levels of carbon emissions. The other is low humidity, which is sometimes known as ‘winter dry’ and can lead to other problems in older people.

As a lack of proper heating has been recognised as the main cause of cold related discomfort, illness and even death in older people, various strategies have been put in place to raise awareness of the importance of staying warm in winter, such as the Age UK ‘Spread the Warmth’ campaign.1 Guidelines from the Health Information and Quality Authority suggest an ideal temperature of 21˚C in living rooms and 18˚

C in bedrooms.2 However, many

Bedroom number

18 16 14 12 10 9 8 4 3 1

Neutral Warm

Slightly warm Warm Warm Warm

Slightly warm Neutral Neutral Warm

0 10 20 30 40 50 60 70 80 90 100 <2˚C Figure 1. The room temperature versus personal perception

studies have reported that rooms are often over heated in winter. For example, one study surveyed 457 residential care homes in London and found the average room temperature was as high as 24˚C.3 A survey of a care home in Edinburgh undertaken by Heriot-Watt University also revealed that the average temperature of more than 40 per cent of the rooms monitored was above 24˚C, while the rest were above 21˚C. Figure 1 shows that some rooms were overheated; for more than 90 per cent of the time, the temperature was above 24˚C. In some rooms it went up to 28-30˚C. In this environment, most residents said they felt

In a care home environment, it is common to set the thermostat to high to keep residents happy, as it is understood that older people prefer a warm room

November 2018 •

‘warm’ or ‘slightly warm’, with choices selected from the following options: ‘cold’, ‘cool’, ‘slightly cool’, ‘neutral’, ‘slightly warm’, ‘warm’, ‘hot’).

The rooms that were described as ‘neutral’ reached a temperature of above 24˚C for 30 per cent of the hours during which they were monitored. In those rooms described as ‘warm’ or ‘slightly warm’ the temperature was above 24˚C for 63 per cent of the time. It is important to note that the wording used reflects personal perception rather than preference and ‘neutral’ refers to achieving balance between energy cost and thermal comfort.

High energy consumption Overheating inevitably leads to excessive energy consumption and consequently high carbon emissions. Unlike most other buildings, care homes run continuously and in countries with cooler climates like the UK, heating is provided for longer periods of the year and for more hours

45 >22˚C, <24˚C >24˚C

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