Not restricted by heating system

Those who are not restricted by their heating system are categorised by their main priority and reasons behind their specific heating use behaviours. The identified priorities within the sample, which resulted in separate heating characters, included cost, comfort, health, environmental attitudes and prioritising others over

themselves.

165 4.6.2.1 Cost

Those occupants who prioritise cost with their heating use are divided into two different heating characters dependant on whether their heating use is dictated by the cost or whether they are extremely conscious of costs. Those referred to as

“fearful heaters” are those whose heating use is directly related to the cost associated with using the energy to heat the home and often these occupants are

“fearful” of receiving a bill which they simply cannot afford. Therefore these occupants are most likely to keep their heating use to a minimum and may choose to only heat specific areas of the dwelling believing that this will reduce the cost.

These occupants will often resort to putting on multiple layers of clothing and having hot drinks or moving around to try and improve their own thermal comfort before resorting to putting the heating on. Often they may also use secondary heating sources in replace of the main central heating system so that they can control the heat better and minimise their heating usage. Those referred to as

“stringent heaters” are not dictated in their heating use by costs to the same extremes that “fearful heaters” are but they are extremely conscious of their heating use and the costs associated to this. Often these occupants may be on prepayment meters or lower incomes and want to try and minimise large bills however still expect to be able to use their heating system as normal, if not just

“stringently”. These occupants are likely to keep their heating use to a minimum and try and stick to the heating schedules they set and use adaptive measures in-between those scheduled heating periods to improve their comfort instead of putting the whole heating system on. These occupants may also make use of secondary heating sources to have localised heating during these non-scheduled heating periods.

4.6.2.2 Comfort

Comfort is a priority for many when heating their homes and is split into two different heating characters, “trade-off heaters” and “exacting heaters”. Those referred to as “trade-off heaters” are those occupants who desire to be comfortable within their own home and see it to be a priority that their home is a warm

166 environment that they are happy to live in. To ensure that they can reach this environment these occupants often make “trade-offs” between other items such as an expensive holiday or new TV. They are careful in maintaining a balance in what they expect in the rest of their day to day lives for the knowledge that they live in a comfortable and warm home. Alternatively the other heating character driven by comfort are those who have quite a high comfort expectation and as such may be referred to as “exacting heaters” due to their “exacting” comfort conditions. These occupants are those who like to “wander round their home in shorts and t-shirts in winter” and to ensure they can achieve this will often have their heating on for long periods of time and/or at much higher set-point temperatures.

4.6.2.3 Health

Some occupants are influenced by health issues with their use of heating within their home and these are referred to as “necessity heaters”. Occupants that fall into this heating character type are those who may be less mobile due to a disability, may have an illness which impacts their thermal comfort, or it may be homes with small babies/young children who require a warmer temperature. Often these occupants heat their homes to ensure they can prevent further illness and therefore it is a “necessity” to them to have it warm. This means that these homes may often have longer heating durations and/or a higher set-point temperature to ensure this comfortable environment lasts throughout the day. These households may also control their heating by the easiest method available to them, in particular if they are less mobile. Therefore they may be more likely to switch the controls on/off rather than use TRVs and more likely to heat the whole house instead of trying to adapt individual rooms to their needs. Similarly those who are less mobile may resort to leaving their heating on longer as they are unable to keep going to the controls to change settings when they feel like it. “Necessity heaters” may benefit from new heating control technologies that are portable and therefore can be placed in an easily accessed area, those with remote access, and those which have some form of temperature feedback so that occupants can see what the

temperature within the dwelling is.

167 4.6.2.4 Environment

Those who prioritise the environment when heating their homes are referred to as

“eco-heaters”. These occupants are very aware of trying to reduce their energy use within their home, not just the energy used for heating and therefore they are very

“eco” in their thinking and actions. “Eco-heaters” are more likely to have

investigated how their heating system works and build up a mental model that lets them understand the impact of their actions on how much energy it equates to, although this may be more in a monetary value of energy rather than the kWh value.

These households are likely to make use of solid fuel options with perhaps wood burners to use reclaimed or recycled wood in as they believe these to be more eco-friendly over central heating. “Eco-heaters” are likely to have more control options to ensure they use their heating system to its optimum efficiency and are likely to have considered or invested in renewable energy sources such as solar hot water heating or solar panels.

4.6.2.5 Others

Finally there are those where their heating character is influenced by prioritising others over themselves and therefore are referred to as “selfless heaters”. These are occupants whose heating use is in relation to others within the household who may have different comfort levels, often resulting in higher temperatures than those which are their own comfort level and therefore they are often “selfless” in how they heat their home to ensure that other occupants are content. These occupants are most likely to take adaptive measures themselves to improve their own comfort such as lower clothing levels or set different areas of the home to different temperatures through use of radiator valves (TRVs or manual) or windows.

Similarly “selfless heaters” may accept a lower comfort level to their own comfort preference, in favour of meeting the comfort needs of others, and again likely to use adaptive measures to improve their own comfort.

168 4.6.3 Summary of heating behaviour taxonomy

Although this heating character taxonomy is not definite, it provides an alternative insight into the reasons for heating use and the impact these have on how the heating system is then used within a property. By understanding the drivers behind heating use in homes it is clear to see how difficult reducing the energy used for space heating within the domestic sector is: certain heating characters may well respond better to new heating control technology than others; one solution or new technology will not fit all households’; and more research is needed into exactly how occupants adapt to new heating controls being installed.

4.7 Discussion

The aim of this study was to uncover how people use their heating in a sample of 30 homes and uncover the reasons, in particular, behind occupants’ preferential method of controlling their heating when more than one option is available (i.e.

thermostat, timer/programmer, radiator valves, thermostatic radiator valves or boiler controls). The main drivers influencing heating use, identified in this study, fell into four categories; comfort, cost, health and energy savings. These align with two of the categories identified by Wei et al, occupant related factors and other factors. Within the occupant related factors identified by Wei et al (2014), the occupants’ own thermal sensation as well as health were identified as influencing factors, which agrees with this study’s finding of comfort and health being driving factors towards heating use. Wei et al (2014) listed heating price and energy use awareness within the other factors category, agreeing with this study’s finding that cost and energy savings can have an influence on occupants’ use of heating in homes. Rathouse & Young (2004) reported the importance of understanding the drivers behind occupants’ use of heating within their home and this study has presented just how varied these drivers can be.

The heating use drivers and heating use characteristics identified in this study were used to develop a new heating use taxonomy, building on the work of Rubens and

169 Knowles (2013) and their heating user types. The heating use taxonomy provides a framework to understand the heating use behaviours of specific characters linked with the driving factors towards heating use for those households. Those with a lack of control or broken systems used workaround solutions to try and achieve the best heating strategy for their home; consequences of these restricted systems have not previously been reported by Rubens and Knowles (2013), Raaij (1983b) or Guerra-Santin (2011). Policy measures aimed at improving energy efficiency may need to address restricted heating systems as a priority, before the energy saving potential of new technologies or retrofit options can be considered.

Participants in this study, despite having multiple methods to control their heating (wall thermostat, timer/programmer, boiler controls, TRVs etc.), reported using one predominant method for reasons of personal choice, usability and accessibility of control options. These findings agree with those reported by Rathouse & Young (2004) that poor positioning of controls (be that positioned too high, too low, somewhere dark, out of reach or hidden away), led to difficulty for occupants to use these heating controls. This has implications on energy use within these homes, as restricted access to control may lead to households heating unused spaces, or leaving their heating on for longer durations than needed. However it should be noted that within this study the interviews only focused on one participant within each household and therefore they may be unaware of how others in the

household adjust the heating. Although the participants inferred as to how others within the household used the heating system, and often reported similar

difficulties for them, it may not reflect exactly what other household members do with the heating system. This is a similar limitation found with previous work (Rubens and Knowles, 2013, Guerra-Santin, 2011, Raaij, 1983b) where the response mainly reflects one individual household member and as such may not show the full picture of heating use within the household.

170 By linking the heating use drivers with the characteristics of heating use, a diversity of drivers and heating use characteristics were uncovered, even within a small sample similar in size to that used by Rubens and Knowles (2013). This study may have identified a larger number of characters due to the level of detail in the taxonomy, however this level of detail about the characters can be used to

understand how people are driven by certain factors when using their heating. This study found 30% of participants reported using their heating in an on/off manner rather than adjusting thermostat temperatures or heating schedules, possibly as a result of the controls being overly complicated for some participants. Controls not being used in an optimum way and changes rarely being made have been reported previously by Caird et al (2007) and Shipworth (2011).

In households with TRVs in this study, 62% reported barely touching them at all, due to participants never considering changing the settings or due to difficulties in the use of the physical device. This finding is similar to that reported by Rathouse &

Young (2004) who reported occupants not interacting with radiator valves and TRVs due to badly located valves, restricting occupants’ access to adjust the settings.

However this study also found participants reporting not interacting with TRVs due to a preference of a uniform temperature throughout their home. This finding suggests that, in those homes, zonal heating control technology may be less likely to be adopted as those households may not see the need for it when content with a uniform temperature. However installing zonal control in households, where existing TRVs are difficult to use or badly located, could result in larger energy savings if householders are willing to set up the system appropriately.

In this study there were those who reported using secondary heating regularly during winter either instead of using the main heating system or in addition to the central heating. 88% of participants reporting the presence of wood burning stoves/fires within their homes also reported regularly using them over winter, often reporting a preference towards using them. This preference was often down

171 to not only the warmth they provide but the sense of well-being which also came from the use of wood burning stoves/fires. This finding agrees with Devine-Wright et al (2014) who reported people’s perception of thermal comfort can be influenced by a feeling of cosiness. Often those reporting using wood burning stoves within this study reported that the heat generated from the stove switched their central heating off due to the heat spreading to the hall where the thermostat was located;

this could result in some energy savings. However, those using secondary heating sources such as portable radiators or gas fires are very room specific and their use is unlikely to cause the thermostat to switch the central heating off, and therefore may be using energy in addition to the energy used by the central heating system.

Due to the in-depth nature of the interviews carried out for this study, the sample size was small and therefore cannot be seen as being representative of the heating behaviours across the UK. However the sample covered a range of demographics, dwelling types and occupancy levels, therefore providing a perspective into the variation in heating use and the reasons behind such use within the sample. The study has presented a taxonomy of heating use which combines heating use behaviours and the influencing factors behind them which can be used as a framework to understand more about how different influencing factors impact heating use in homes to help target new heating policy and technology more effectively. In particular, the problem of some occupants dealing with ill-working heating systems highlights that some households may require a focus on fixing problems with the heating system first before trying to improve it with new technology. The study has also shown wood burning stoves/fires being used not just for additional warmth as secondary heating sources but also for achieving a sense of well-being and cosiness within the home. Overall this study has shown that heating use in homes is extremely varied and the reasons behind heating use

behaviours are not necessarily always determined by user preference.

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Chapter 5: How do people actually