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Comfort for all: fantastic dream or emerging reality?
Are you sitting comfortably? Then Get Sust will begin its wintry tale – the ongoing saga of how post-occupancy evaluation, basic energy-efficiency measures and a sprinkling of government subsidies could deliver sustainable indoor comfort to the nation.
'Are you sitting comfortably?' – the phrase that launches a thousand fairytales has a deeper meaning for everyone involved in sustainability and the built environment. We're not talking desk height and screen breaks here, but good old-fashioned comfort – warmth, fresh air, glare-free lighting and acceptable levels of noisy distractions.
The drive to improve the energy efficiency and sustainability of buildings – to find out how they operate in practice and devise steps to reduce energy consumption – is closely entwined with the need to improve comfort. Health and sustainability neatly dovetail in what ought to be a virtuous circle of improvements. The difficulties come in understanding exactly what 'comfort' means, knowing what sort of external conditions we will need to temper in the future, and finding cost-effective ways to help those who are most in need.
Who knows what tomorrow brings?
It's a frosty old cliché, but true nonetheless, that the British love to talk about the weather. It's hardly surprising, when we have so much of it! December 2010 was one of the coldest Decembers in over 100 years, with average temperatures 5°C below the 1971–2000 average. Despite this, the Met Office confirmed that, globally, 2010 was one of the warmest years on record. Fast forward, and the last few months of 2011 have delivered unseasonal mildness – November 2011 was the second warmest November in over 100 years with only that of 1994 being warmer. We never really know what our wintery weather is going to throw at us.
At the global level, the Intergovernmental Panel on Climate Change (IPCC), the international guardian of climate-related statistics and predictions, published its 'special report on extreme weather' in November 2011. The report concludes that heavier rainfall, fiercer storms and harsher droughts are on the cards for developing countries, with problems for developed nations likely to include damaging heatwaves.
Although no one can say with 100% certainty what future outdoor conditions will be like, we can be certain that Homo sapiens cannot physiologically adapt quickly, so we will become ever more reliant on our buildings to shelter us from extremes.
When it comes to temperature, people have pretty exacting requirements. The comfort zone for most of us, most of the time, is 18-24°C. Too hot and we slow right down. If the heat is prolonged and extreme, we risk dehydration and heat exhaustion, possibly culminating in heart attack. And when things get cool and the temperature dips to 16°C, there is an increasing risk of respiratory disorders for people who are generally sedentary, particularly the ill and infirm or people with ongoing medical conditions such as asthma. For these people, when the temperature gets down to 12°C, the increased viscosity of the blood begins to put a strain on the heart and cardiovascular system, and hypothermia can begin after just a couple of hours' exposure to temperatures of around 9°C (the Health & Safety Executive provides guidance on work-related temperature requirements, while CIBSE Guide A offers definitive design guidelines for low-energy, sustainable indoor environments).
New ways to think about comfort
Current Building Regulations and related building services design guidance aim to deliver new buildings that meet our needs over the short- to medium-term, but there is always a need to be thinking ahead, and researchers are developing today the building modelling tools that will be used 10 or more years hence to design buildings for the unknowable climate of the 2100s. A team in the Netherlands, for instance, has recently published the results of its work to develop a mathematical model of 'thermal sensation', which could enhance building performance modelling techniques because it offers a more realistic view of comfort, based on neurophysiology rather than actual room temperatures.
Writing in the journal Indoor Air (Vol. 21, Issue 6), Boris Kingma and colleagues explain that humans do not sense temperature directly; sensations of warmth or cold are transmitted to the brain as neurological signals and there is a feedback mechanism which operates to regulate core body temperature in relation to surface temperature. The researchers used this knowledge to develop and test a more sophisticated model of human thermal comfort which, in turn, can enhance building modelling techniques.
Lighting is another aspect of comfort that can have a detrimental, though generally less dramatic, impact on people's health. Campaigns to use low-energy lighting in both homes and non-domestic buildings have successfully demonstrated the energy benefits of paying attention to lighting levels. But in terms of comfort, 'control' is king – especially in the office environment. At a November 2011 workshop organized by the network group SPONGE, Faye Wade, a graduate student at University College London (UCL), reported the results of her investigation of how human nature affects our behaviour in shared environments, i.e. do squabbles over lighting controls in open plan offices undermine their usefulness.
Providing lighting control over and above the basic on-off switch is known to improve occupant satisfaction in offices, but the success of a control strategy depends on how much natural light is reaching the person who wields the controller. Her study, of a new open-plan university office building, used the Building Use Studies (BUS) survey to gather occupants' feedback about the office lighting and controls, and analysed the feedback in relation to quantitative data on lux levels. Part of the methodology involved calculating and comparing the 'disagreement index' of groups of occupants. Although Wade did not observe any fighting over the lighting controller in this instance, her results did yield some ideas for immediate energy-saving improvements!
Wade's work is one of a swathe of graduate student reports collected by the Network for Comfort and Energy Use in Buildings (NCEUB), which is organized by some of the leading international experts on indoor comfort. The NCEUB's work covers the wide range of comfort issues and all building types.
The cold facts about existing buildings
While it is true that comfort is predominantly a subjective issue, it is now well-established that ongoing exposure to poor-quality indoor environments can be very detrimental to health and well-being. The link was first acknowledged by the World Health Organization in 1984, and the link between low indoor temperature and morbidity in the elderly was established in a UK Medical Research Council paper published in 1986 ('Low indoor temperatures and morbidity in the elderly', K. J. Collins, Age and Ageing).
In the UK, the Home Energy Conservation Act (HECA) of 1995 required local authorities to take steps to consider measures to improve the energy efficiency of all residential accommodation in their locality, and many councils targeted efforts at social housing and people living in 'fuel poverty' (where a household needs to spend more than 10% of its income to maintain an adequate level of warmth). Despite this and numerous cash-back and incentive schemes to help low-income households improve their energy efficiency, the problem remains and, with rocketing fuel prices, could get worse.
In May 2011, Professor Sir Michael Marmot, president of the British Medical Association, published the results of a major study by his team at UCL's Institute of Health Equity, The health impacts of cold homes and fuel poverty, which concluded that cold British homes increase the risk of mental and physical illness in children and young people. The report, co-sponsored by numerous charities, plus Friends of the Earth, the Chartered Institute of Environmental Health and National Energy Action, estimated that in 2009/2010 there were 25,400 excess winter deaths (EWDs), and that more than 20% of all EWDs can be attributed to the coldest quarter of the national housing stock, over and above the number of deaths that would have occurred in these homes regardless of the weather. Some 1.3 million children – equivalent to 13% of all children – live in homes that are at the bottom of the energy rating scale (i.e. rated F or G).
At the most fundamental level, these are people who have little control over their own comfort, and face the double whammy of being unable to avoid wasting costly warmth because of leaky building fabric or poorly performing appliances.
Shocking statistics, whatever the economic climate: what is being done about it?
The government's Warm Front scheme was relaunched in April 2011, with the aim of helping 90,000 low-income households to install energy-saving measures, particularly insulation, over two years (£110 million available in 2011/12 and £100 million in 2012/13). The government also warned the energy companies that they needed to work harder to improve their performance under the Carbon Emission Reduction Target (CERT), which obliges the main energy suppliers to help customers install energy-efficiency measures. That scheme has not performed as well as planned – indeed prior to its relaunch it had become notorious for the over-generous supply of energy-efficient light bulbs to puzzled homeowners. In 2010, new requirements were introduced to make companies concentrate on installing insulation. So far, so good.
Then in late November 2011, the Department for Energy and Climate Change (DECC) launched a consultation on its new approach, the Green Deal, which will introduce the Energy Company Obligation (ECO) to replace CERT and the Community Energy Saving Programme (CESP), both of which will expire in 2012. It remains to be seen whether the energy companies will meet their current obligations or wait until the new regime is in place. Either way, there will still be a lot of families in cold and damp homes this winter.
Taking control of comfort
Those who are outside the target groups for government-backed schemes, yet who are struggling with rising fuel bills and uncomfortable conditions, need to find other ways to combat indoor discomfort. UCL PhD student Carrie Behar reported on one such case study at the SPONGE networking meeting in November. She has been working closely with residents at the Barbican development in central London to deliver a post-occupancy evaluation (POE) of more than 2000 flats in the estate by assessing occupants' overall satisfaction with their homes. Built in the 1960s, these Grade II listed apartments are of solid concrete construction with timber-framed single glazing, no insulation and electric underfloor heating which is centrally controlled. Not surprisingly, the dwellings have poor energy performance and thermal bridging problems. However, Behar found that the residents generally like their homes and rate them highly on the BUS scale for comfort, satisfaction and forgiveness.
However, her study revealed that the main way residents control indoor temperatures is by opening windows – wasting high-cost electrical heating. Worse still, the heating is charged as an average of delivered heat, so wasted heat puts up the bills of all residents, regardless of whether they were trying to conserve energy.
Conventional solutions, such as installing insulation, are not straightforward for these Grade II listed properties, but Behar's study identified some classic low-hanging fruit that will have an immediate impact on energy usage and occupant comfort: simply teaching residents how to change their hot water thermostats and deploy the trimmers which are the only way of controlling temperatures within each flat.
As numerous reports collected by NCEUB attest, there are many small and low-cost ways to improve the energy efficiency of buildings, but when it comes to comfort, there is mounting evidence that nothing works quite like putting the people in control.
Related NBS information:
- BREEAM Assessment methods
- Environmental construction: methods of assessing buildings
- Before you start building "green"
Written December 2011
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