How do people really use their homes?

By - , Build 121

It’s vital for a designer to understand how occupants will use their new home. But equally, the new owner needs to understand how to make the most of the design.

A research journal from the United Kingdom, Building Research and Information, recently published a special issue on ‘housing occupancy feedback’, which emphasised not only the physical structure of a house but how it’s used. As BRANZ is an international leader in this field, the journal included a paper on BRANZ’s Household Energy End-use Project (HEEP) discussing the choices that occupants make about heating their houses in winter. Results of the 10-year HEEP study have been covered in Build extensively, so we will look at the findings of the other papers here.

The other seven papers support HEEP’s findings and question whether designers and regulators pay enough attention to how people use their houses in practice.

Simplicity and user manual needed

A project at the United Kingdom’s BRE Innovation Park examined how the occupants of a prototype low-energy house adapted their behaviours to their new environment. It found that occupants need a careful introduction to the complexities of their new house if they are to accrue the benefits. In this instance, the advanced energy system in the house was unreliable and overly complex.

As a result of the study, the designers simplified the building envelope, energy systems and controls and made considerable changes to its ‘home guide’ – a user manual for the house, akin to the user manual that comes with a new car. BRANZ has advocated such user manuals for some time, but they are yet to become commonplace.

Occupants’ choices may differ from models

Two other studies from the United Kingdom emphasised the importance of occupants’ decisions. The first study compared the performances of 25 houses rated ‘excellent’ by the EcoHomes rating tool. It found that some houses in the group consume 3.5 times more power per square metre and 5 times more water per person than others, although all performed well when compared to the regional average. Through interviews, the research team found that much of this variability was due to occupant behaviour.

The second study questioned the occupants of two houses that were due to be refurbished. Researchers asked what they felt was the least satisfactory aspect of their homes and how this influenced their refurbishment decisions. They found that fuel costs in both houses were vastly different than models predicted – knowledge that helped designers select the options that would have the most benefit.

A Canadian project went a step further. It compared consumers in a range of residential developments, but went beyond individual perceptions and preferences to examine the wider interactions within the neighbourhoods. It found that occupants of high-performance ‘green’ buildings, typical multi-residential buildings and co-housing buildings behave very differently, which suggests that building governance and management, and social networks, also play significant roles. Researchers conclude that a single approach is unlikely to change the expectations and behaviours of all householders.

Building Code may be out of touch with occupants

An Australian paper looked at how their Building Code interacts with low-energy housing concepts. Researchers selected five houses that were recognised for sustainability or general residential design by the Australian Institute of Architects.

In use, all five were low energy-users and greenhouse gas-emitters for houses of their size and were highly rated as living spaces by their occupants. But when energy efficiency and greenhouse gas emissions were modelled, researchers discovered that none of the houses complied with the Australian Building Code because it relies on a computer model that assumes occupants will act and control their house in certain ways. The study showed that occupants of the five houses did not follow the standard pattern of behaviour and concluded that building regulations may not recognise the goals of occupants and reward potential good behaviours.

A Dutch project installed smart electricity meters in houses and studied their effect on electricity usage. Across 54 houses, it found a 7.8% reduction in energy use across a 4-month period when compared to the previous year, but the reduction was down to 2% a year later as only 30 houses had sustained the lower rate of consumption. However, in 14 households that routinely related to the meter, the average saving for the same 4-month period was nearly 17% and still 8% a year later.

Like one of the UK studies, the Dutch researchers suggest that the technology has potential, but both suppliers and customers need to understand it better before they will see any real benefits.

Know your user

These studies all point towards a common truth: pay attention to how people use their houses. No matter what the benefit, whether it’s lower energy consumption, lower water usage or a safer and healthier environment, the best energy, water, fire or maintenance modelling means very little if occupants do not use the building the way you expect. It is essential to integrate technical performance and occupant behaviour to achieve the best result.

The findings also emphasise how important it is to consider both the physical structure of a house and how the occupants will use it. BRANZ plans to publish its own 2010 House Condition Survey, which combines inspection data and occupants’ opinions of their homes, in mid 2011.

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